IB Biology SL Flashcards: Complete Course Review
Review the current IB Biology Standard Level course with 960 independently written active-recall cards covering all 34 SL topics across molecules, cells, organisms, genetics, evolution, and ecology.
Sobre este baralho
Study the current IB Biology SL course with 960 independently written English flashcards. The deck covers all 34 Standard Level topics through four broad groups: molecules and cells; metabolism and genetics; organisms and systems; and evolution and ecology.
Cards move from essential terms and structures to functions, mechanisms, comparisons, predictions, and compact interpretation prompts. Useful two-way term cards are separated by at least three unrelated cards, while explanatory answers are kept in the direction that supports meaningful recall. Every card carries the root tag ib-bio-sl and exactly one broad group tag.
The order introduces prerequisite ideas before dependent ones and progresses from simpler recall to more demanding reasoning within each topic. The deck is designed for ongoing spaced review. It does not replace data-heavy practice papers, extended-response practice, laboratory work, or the scientific investigation.
Reviewed in 2026 against the current Biology Standard Level course, first assessed in 2025.
Independent, unofficial study aid based on common biological knowledge. Not affiliated with or endorsed by the International Baccalaureate Organization. No copied IB examination questions, mark schemes, or curriculum text are included.
Check the official IB Biology course page for authoritative requirements.
Cartões deste baralho
Cartão 1
Pergunta
What is water polarity?
Resposta
The unequal sharing of electrons in a water molecule, giving oxygen a partial negative charge and the hydrogens partial positive charges.
Cartão 2
Pergunta
What is a hydrogen bond?
Resposta
A weak attraction between a partially positive hydrogen atom and a partially negative atom in another molecule.
Cartão 3
Pergunta
What is cohesion?
Resposta
Attraction between molecules of the same substance.
Cartão 4
Pergunta
What is adhesion?
Resposta
Attraction between molecules of different substances.
Cartão 5
Pergunta
Which term describes unequal charge distribution within a water molecule?
Resposta
water polarity
Cartão 6
Pergunta
Which term describes the intermolecular attraction that links neighboring water molecules?
Resposta
a hydrogen bond
Cartão 7
Pergunta
Which term describes attraction between molecules of the same substance?
Resposta
cohesion
Cartão 8
Pergunta
Which term describes attraction between water and a different material?
Resposta
adhesion
Cartão 9
Pergunta
What is a solvent?
Resposta
A liquid that dissolves solutes to form a solution.
Cartão 10
Pergunta
What is specific heat capacity?
Resposta
The energy required to raise the temperature of a unit mass of a substance by one degree.
Cartão 11
Pergunta
What is latent heat of vaporization?
Resposta
The energy required to vaporize a specified amount of liquid without changing its temperature.
Cartão 12
Pergunta
Why does ice float on liquid water?
Resposta
Hydrogen bonds hold water molecules in an open lattice in ice, making ice less dense than liquid water.
Cartão 13
Pergunta
Which term describes a liquid that dissolves solutes?
Resposta
a solvent
Cartão 14
Pergunta
Which term describes the energy needed to raise a unit mass by one degree?
Resposta
specific heat capacity
Cartão 15
Pergunta
Which term describes the energy needed to vaporize a liquid without a temperature change?
Resposta
latent heat of vaporization
Cartão 16
Pergunta
Which property of water makes sweating an effective cooling mechanism?
Resposta
Water absorbs substantial energy as it evaporates; the highest-energy molecules leave, carrying heat away from the skin.
Cartão 17
Pergunta
Why does water resist rapid temperature change?
Resposta
Many hydrogen bonds must absorb energy before molecular motion increases substantially, giving water a high specific heat capacity.
Cartão 18
Pergunta
How do cohesion and adhesion support water transport in narrow tubes?
Resposta
Cohesion keeps water molecules connected, while adhesion helps the water column cling to the tube wall.
Cartão 19
Pergunta
How does water participate differently in hydrolysis and condensation?
Resposta
Hydrolysis consumes water to split a bond; condensation forms a bond and releases water.
Cartão 20
Pergunta
How does floating ice protect aquatic life in winter?
Resposta
Surface ice insulates the liquid water below, slowing further heat loss and preventing the whole body of water from freezing rapidly.
Cartão 21
Pergunta
Why is water effective for transporting many biological solutes?
Resposta
Its polarity allows ions and other polar molecules to become surrounded and dispersed in solution.
Cartão 22
Pergunta
Why do nonpolar substances tend to cluster in water?
Resposta
Clustering reduces the nonpolar surface exposed to water, allowing more water molecules to maintain hydrogen-bond interactions.
Cartão 23
Pergunta
What is a nucleotide?
Resposta
A nucleic-acid monomer made of a pentose sugar, a phosphate group, and a nitrogenous base.
Cartão 24
Pergunta
What is a nucleoside?
Resposta
A nitrogenous base joined to a pentose sugar, without a phosphate group.
Cartão 25
Pergunta
What is a phosphodiester bond?
Resposta
A covalent bond linking the phosphate of one nucleotide to the sugar of the next nucleotide.
Cartão 26
Pergunta
What is DNA?
Resposta
A usually double-stranded nucleic acid that stores hereditary information in its base sequence.
Cartão 27
Pergunta
Which term describes a sugar-phosphate-base monomer?
Resposta
a nucleotide
Cartão 28
Pergunta
Which term describes a base joined to a sugar but no phosphate?
Resposta
a nucleoside
Cartão 29
Pergunta
Which term describes the covalent linkage in a nucleic-acid sugar-phosphate backbone?
Resposta
a phosphodiester bond
Cartão 30
Pergunta
Which term describes the nucleic acid that usually stores hereditary information?
Resposta
DNA
Cartão 31
Pergunta
What is RNA?
Resposta
A usually single-stranded nucleic acid involved in expressing and regulating genetic information.
Cartão 32
Pergunta
What are antiparallel DNA strands?
Resposta
Two DNA strands that run in opposite 5′ to 3′ directions.
Cartão 33
Pergunta
What is complementary base pairing?
Resposta
Specific pairing in which adenine pairs with thymine in DNA, or uracil in RNA, and cytosine pairs with guanine.
Cartão 34
Pergunta
What is a purine?
Resposta
A nitrogenous base with two fused rings; adenine and guanine are purines.
Cartão 35
Pergunta
Which term describes the usually single-stranded nucleic acid used in gene expression?
Resposta
RNA
Cartão 36
Pergunta
Which term describes DNA strands running in opposite directions?
Resposta
antiparallel DNA strands
Cartão 37
Pergunta
Which term describes specific A–T or A–U and C–G pairing?
Resposta
complementary base pairing
Cartão 38
Pergunta
Which term describes a two-ring nitrogenous base?
Resposta
a purine
Cartão 39
Pergunta
What is a pyrimidine?
Resposta
A nitrogenous base with one ring; cytosine, thymine, and uracil are pyrimidines.
Cartão 40
Pergunta
What is a genome?
Resposta
The complete genetic material of an organism or cell.
Cartão 41
Pergunta
What three structural features commonly distinguish RNA from DNA?
Resposta
RNA usually contains ribose, uses uracil instead of thymine, and is single-stranded rather than double-stranded.
Cartão 42
Pergunta
What determines the base sequence of the second DNA strand?
Resposta
Complementary base-pairing rules determine it: A pairs with T, and C pairs with G.
Cartão 43
Pergunta
Which term describes a one-ring nitrogenous base?
Resposta
a pyrimidine
Cartão 44
Pergunta
Which term describes the complete genetic material of an organism?
Resposta
a genome
Cartão 45
Pergunta
What do the 5′ and 3′ labels of a nucleic-acid strand refer to?
Resposta
They refer to numbered carbon atoms in the pentose sugar and define the strand's chemical direction.
Cartão 46
Pergunta
Where is genetic information encoded in DNA?
Resposta
In the order of nitrogenous bases along the DNA strand.
Cartão 47
Pergunta
Why is ATP classified as a nucleotide?
Resposta
It contains adenine, ribose, and phosphate groups, the three component types of a nucleotide.
Cartão 48
Pergunta
How do mRNA, tRNA, and rRNA contribute to protein synthesis?
Resposta
mRNA carries the coding sequence, tRNA delivers amino acids, and rRNA forms the catalytic and structural core of ribosomes.
Cartão 49
Pergunta
How are a gene and a chromosome related?
Resposta
A gene is a DNA sequence with a biological function; a chromosome is one long DNA molecule containing many genes and other sequences.
Cartão 50
Pergunta
What happens to double-stranded DNA when it is denatured by heat?
Resposta
Hydrogen bonds between complementary bases break and the two strands separate; the covalent backbones usually remain intact.
Cartão 51
Pergunta
Why can each DNA strand serve as a template during replication?
Resposta
Its base sequence determines a complementary sequence through specific base pairing.
Cartão 52
Pergunta
In which direction are new nucleic-acid strands synthesized?
Resposta
Nucleotides are added to the 3′ end, so synthesis proceeds 5′ to 3′.
Cartão 53
Pergunta
What is a monosaccharide?
Resposta
A single sugar unit that can serve as a carbohydrate monomer.
Cartão 54
Pergunta
What is a disaccharide?
Resposta
A carbohydrate formed from two monosaccharides joined by a glycosidic bond.
Cartão 55
Pergunta
What is a polysaccharide?
Resposta
A polymer made from many monosaccharide units.
Cartão 56
Pergunta
What is a glycosidic bond?
Resposta
A covalent bond joining monosaccharides in a carbohydrate.
Cartão 57
Pergunta
Which term describes a single sugar unit?
Resposta
a monosaccharide
Cartão 58
Pergunta
Which term describes two monosaccharides joined together?
Resposta
a disaccharide
Cartão 59
Pergunta
Which term describes a polymer of many sugar units?
Resposta
a polysaccharide
Cartão 60
Pergunta
Which term describes the covalent linkage between monosaccharides?
Resposta
a glycosidic bond
Cartão 61
Pergunta
What is a triglyceride?
Resposta
A lipid formed from glycerol joined to three fatty acids.
Cartão 62
Pergunta
What is a fatty acid?
Resposta
A hydrocarbon chain with a carboxyl group that can form part of many lipids.
Cartão 63
Pergunta
What is a saturated fatty acid?
Resposta
A fatty acid with no carbon-carbon double bonds in its hydrocarbon chain.
Cartão 64
Pergunta
What is a phospholipid?
Resposta
An amphipathic lipid with a phosphate-containing hydrophilic head and hydrophobic fatty-acid tails.
Cartão 65
Pergunta
Which term describes glycerol joined to three fatty acids?
Resposta
a triglyceride
Cartão 66
Pergunta
Which term describes a hydrocarbon chain ending in a carboxyl group?
Resposta
a fatty acid
Cartão 67
Pergunta
Which term describes a fatty acid without carbon-carbon double bonds?
Resposta
a saturated fatty acid
Cartão 68
Pergunta
Which term describes a lipid with a polar head and nonpolar tails?
Resposta
a phospholipid
Cartão 69
Pergunta
How is a glycosidic bond formed between two monosaccharides?
Resposta
A condensation reaction joins them and releases a molecule of water.
Cartão 70
Pergunta
How is a polysaccharide broken into smaller sugars?
Resposta
Hydrolysis adds water across glycosidic bonds, splitting the polymer.
Cartão 71
Pergunta
Which polysaccharides store glucose in plants and animals?
Resposta
Starch stores glucose in plants; glycogen stores glucose in animals and fungi.
Cartão 72
Pergunta
Why is cellulose suitable for plant cell walls?
Resposta
Its straight β-glucose chains hydrogen-bond into strong microfibrils that resist stretching.
Cartão 73
Pergunta
Why do lipids store more energy per gram than carbohydrates?
Resposta
Lipids contain more energy-rich carbon-hydrogen bonds and are more reduced.
Cartão 74
Pergunta
Why do phospholipids form bilayers in water?
Resposta
Hydrophilic heads interact with water while hydrophobic tails cluster away from water.
Cartão 75
Pergunta
Besides energy storage, what are three biological roles of lipids?
Resposta
They form membranes, provide thermal insulation and cushioning, and can act as signaling molecules.
Cartão 76
Pergunta
How do cis double bonds affect fatty-acid packing and melting point?
Resposta
They introduce bends that reduce close packing, usually lowering the melting point.
Cartão 77
Pergunta
What is an amino acid?
Resposta
A protein monomer with an amino group, a carboxyl group, a hydrogen, and a variable R group attached to a central carbon.
Cartão 78
Pergunta
What is a peptide bond?
Resposta
The covalent bond formed between the amino group of one amino acid and the carboxyl group of another.
Cartão 79
Pergunta
What is a polypeptide?
Resposta
A chain of amino acids joined by peptide bonds.
Cartão 80
Pergunta
What is protein primary structure?
Resposta
The amino-acid sequence of a polypeptide.
Cartão 81
Pergunta
Which term describes a protein monomer with amino, carboxyl, and variable R groups?
Resposta
an amino acid
Cartão 82
Pergunta
Which term describes the covalent linkage between amino acids?
Resposta
a peptide bond
Cartão 83
Pergunta
Which term describes a chain of peptide-linked amino acids?
Resposta
a polypeptide
Cartão 84
Pergunta
Which term describes a protein's amino-acid sequence?
Resposta
protein primary structure
Cartão 85
Pergunta
What is protein secondary structure?
Resposta
Local folding such as α-helices and β-sheets stabilized mainly by backbone hydrogen bonds.
Cartão 86
Pergunta
What is protein tertiary structure?
Resposta
The overall three-dimensional shape of one polypeptide produced by interactions among R groups and the backbone.
Cartão 87
Pergunta
What is protein quaternary structure?
Resposta
The arrangement of multiple polypeptide subunits in one functional protein.
Cartão 88
Pergunta
What is protein denaturation?
Resposta
Loss of a protein's normal three-dimensional shape and therefore usually its function.
Cartão 89
Pergunta
Which term describes local α-helix and β-sheet folding?
Resposta
protein secondary structure
Cartão 90
Pergunta
Which term describes the overall three-dimensional shape of one polypeptide?
Resposta
protein tertiary structure
Cartão 91
Pergunta
Which term describes the association of multiple polypeptide subunits?
Resposta
protein quaternary structure
Cartão 92
Pergunta
Which term describes loss of a protein's native shape?
Resposta
protein denaturation
Cartão 93
Pergunta
What mainly gives different amino acids their different chemical properties?
Resposta
Their variable R groups.
Cartão 94
Pergunta
What reaction forms a peptide bond?
Resposta
A condensation reaction releases water as the amino and carboxyl groups join.
Cartão 95
Pergunta
Why can high temperature denature a protein?
Resposta
Increased molecular motion disrupts weak interactions that maintain the protein's shape.
Cartão 96
Pergunta
Why can extreme pH denature a protein?
Resposta
It changes the charges of R groups and disrupts ionic and hydrogen-bond interactions.
Cartão 97
Pergunta
How do fibrous and globular proteins generally differ?
Resposta
Fibrous proteins are elongated and mainly structural; globular proteins are compact and often perform dynamic functions.
Cartão 98
Pergunta
Why is three-dimensional shape crucial to protein function?
Resposta
It creates specific binding, catalytic, structural, or interaction surfaces.
Cartão 99
Pergunta
Name four broad biological roles of proteins.
Resposta
Catalysis, transport, signaling, defense, movement, and structural support are major roles; any four are sufficient.
Cartão 100
Pergunta
How can changing one amino acid alter protein function?
Resposta
The substitution can change R-group interactions, folding, stability, or an active or binding site.
Cartão 101
Pergunta
What is cell theory?
Resposta
The principles that living organisms are made of cells, cells are the basic units of life, and cells arise from pre-existing cells.
Cartão 102
Pergunta
What is a prokaryotic cell?
Resposta
A cell without a nucleus or other membrane-bound organelles.
Cartão 103
Pergunta
What is a eukaryotic cell?
Resposta
A cell with DNA enclosed in a nucleus and with membrane-bound organelles.
Cartão 104
Pergunta
What is the nucleus?
Resposta
The double-membrane organelle that contains most of a eukaryotic cell's DNA.
Cartão 105
Pergunta
Which term describes the principles describing cells as life's basic units?
Resposta
cell theory
Cartão 106
Pergunta
Which term describes a cell lacking a nucleus and membrane-bound organelles?
Resposta
a prokaryotic cell
Cartão 107
Pergunta
Which term describes a cell with a nucleus and membrane-bound organelles?
Resposta
a eukaryotic cell
Cartão 108
Pergunta
Which term describes the organelle containing most eukaryotic DNA?
Resposta
the nucleus
Cartão 109
Pergunta
What is a ribosome?
Resposta
A molecular complex of rRNA and proteins that synthesizes polypeptides.
Cartão 110
Pergunta
What is the cytoplasm?
Resposta
The material inside the plasma membrane but outside the nucleus, including cytosol and organelles.
Cartão 111
Pergunta
What is the plasma membrane?
Resposta
The selectively permeable boundary separating a cell from its environment.
Cartão 112
Pergunta
What is a cell wall?
Resposta
A rigid extracellular layer that supports and protects cells in plants, fungi, and most prokaryotes.
Cartão 113
Pergunta
Which term describes the complex that synthesizes polypeptides?
Resposta
a ribosome
Cartão 114
Pergunta
Which term describes cell contents inside the plasma membrane but outside the nucleus?
Resposta
the cytoplasm
Cartão 115
Pergunta
Which term describes the selectively permeable cell boundary?
Resposta
the plasma membrane
Cartão 116
Pergunta
Which term describes a rigid extracellular support layer?
Resposta
a cell wall
Cartão 117
Pergunta
What is the nucleoid?
Resposta
The non-membrane-bound region containing the main chromosome of a prokaryotic cell.
Cartão 118
Pergunta
What is the cytoskeleton?
Resposta
A dynamic network of protein filaments involved in cell shape, transport, division, and movement.
Cartão 119
Pergunta
What structures are shared by all cells?
Resposta
A plasma membrane, cytoplasm, genetic material, and ribosomes.
Cartão 120
Pergunta
Which structures distinguish a typical plant cell from a typical animal cell?
Resposta
A plant cell has a cellulose wall, chloroplasts in photosynthetic tissues, and a large central vacuole; an animal cell lacks these.
Cartão 121
Pergunta
Which term describes the prokaryotic chromosome-containing region?
Resposta
the nucleoid
Cartão 122
Pergunta
Which term describes the internal network of protein filaments?
Resposta
the cytoskeleton
Cartão 123
Pergunta
How is genetic material commonly organized in a prokaryotic cell?
Resposta
The main DNA is usually one circular chromosome in the nucleoid, often accompanied by smaller plasmids.
Cartão 124
Pergunta
How is microscope magnification calculated?
Resposta
Magnification = image size ÷ actual size, using the same units.
Cartão 125
Pergunta
What does microscope resolution describe?
Resposta
The ability to distinguish two close points as separate.
Cartão 126
Pergunta
Arrange these from smallest to largest: ribosome, bacterium, animal cell.
Resposta
Ribosome, bacterium, animal cell.
Cartão 127
Pergunta
How does the cytoskeleton support intracellular transport?
Resposta
Motor proteins move vesicles and other cargo along cytoskeletal filaments.
Cartão 128
Pergunta
Why does a small cell usually exchange materials more efficiently than a geometrically similar large cell?
Resposta
It has a larger surface-area-to-volume ratio, providing more exchange surface per unit of cell contents.
Cartão 129
Pergunta
Why is a cell more than a collection of isolated molecules?
Resposta
Organized interactions among components produce emergent functions such as metabolism, regulation, and reproduction.
Cartão 130
Pergunta
What major advantage do membrane-bound organelles give eukaryotic cells?
Resposta
They separate incompatible reactions and create specialized local conditions.
Cartão 131
Pergunta
What is a phospholipid bilayer?
Resposta
A double layer of phospholipids with hydrophilic heads facing water and hydrophobic tails facing inward.
Cartão 132
Pergunta
What is the fluid mosaic model?
Resposta
A model describing membranes as mobile phospholipids containing a changing mosaic of proteins and other components.
Cartão 133
Pergunta
What is an integral membrane protein?
Resposta
A protein embedded in the bilayer, often spanning it.
Cartão 134
Pergunta
What is a peripheral membrane protein?
Resposta
A protein attached to a membrane surface rather than embedded in the bilayer.
Cartão 135
Pergunta
Which term describes a double phospholipid layer with inward-facing tails?
Resposta
a phospholipid bilayer
Cartão 136
Pergunta
Which term describes the model of a mobile lipid layer containing varied proteins?
Resposta
the fluid mosaic model
Cartão 137
Pergunta
Which term describes a protein embedded within the lipid bilayer?
Resposta
an integral membrane protein
Cartão 138
Pergunta
Which term describes a protein attached to a membrane surface?
Resposta
a peripheral membrane protein
Cartão 139
Pergunta
What is membrane cholesterol?
Resposta
An amphipathic lipid that buffers membrane fluidity and reduces permeability in animal cells.
Cartão 140
Pergunta
What is a glycoprotein?
Resposta
A protein with an attached carbohydrate chain, often used in recognition, adhesion, or signaling.
Cartão 141
Pergunta
What is diffusion?
Resposta
Net movement of particles from a region of higher concentration to lower concentration due to random motion.
Cartão 142
Pergunta
What is osmosis?
Resposta
Net movement of water across a selectively permeable membrane from higher water potential to lower water potential.
Cartão 143
Pergunta
Which term describes the animal-membrane lipid that buffers fluidity?
Resposta
membrane cholesterol
Cartão 144
Pergunta
Which term describes a carbohydrate-bearing protein?
Resposta
a glycoprotein
Cartão 145
Pergunta
Which term describes net movement down a concentration gradient?
Resposta
diffusion
Cartão 146
Pergunta
Which term describes net water movement across a selectively permeable membrane?
Resposta
osmosis
Cartão 147
Pergunta
What is facilitated diffusion?
Resposta
Passive movement down a gradient through a membrane channel or carrier protein.
Cartão 148
Pergunta
What is active transport?
Resposta
Energy-requiring movement of a substance against its concentration or electrochemical gradient.
Cartão 149
Pergunta
Why is the phospholipid bilayer selectively permeable?
Resposta
Its hydrophobic interior allows small nonpolar molecules through more readily than ions and most large or polar molecules.
Cartão 150
Pergunta
How do simple diffusion and facilitated diffusion differ?
Resposta
Both are passive, but facilitated diffusion uses specific membrane proteins while simple diffusion passes through the bilayer.
Cartão 151
Pergunta
Which term describes passive transport through a channel or carrier?
Resposta
facilitated diffusion
Cartão 152
Pergunta
Which term describes energy-dependent transport against a gradient?
Resposta
active transport
Cartão 153
Pergunta
How do channel and carrier proteins differ?
Resposta
Channels provide hydrophilic pores; carriers bind solutes and change shape to move them.
Cartão 154
Pergunta
How can an ATP-driven pump maintain an ion gradient?
Resposta
It couples ATP hydrolysis to a conformational change that moves ions against their electrochemical gradient.
Cartão 155
Pergunta
How does endocytosis move material into a cell?
Resposta
The plasma membrane folds inward and pinches off a vesicle containing the material.
Cartão 156
Pergunta
How does exocytosis move material out of a cell?
Resposta
An intracellular vesicle fuses with the plasma membrane and releases its contents outside.
Cartão 157
Pergunta
What happens to an animal cell in a strongly hypotonic solution?
Resposta
Water enters by osmosis; without a cell wall, the cell may swell and lyse.
Cartão 158
Pergunta
Does molecular movement stop when diffusion reaches equilibrium?
Resposta
No. Molecules continue moving randomly, but there is no net movement between regions.
Cartão 159
Pergunta
How does decreasing temperature generally affect membrane fluidity?
Resposta
It reduces phospholipid movement and makes the membrane less fluid.
Cartão 160
Pergunta
Why do unsaturated fatty-acid tails increase membrane fluidity?
Resposta
Their cis double-bond bends prevent phospholipids from packing tightly.
Cartão 161
Pergunta
What changes increase the rate of simple diffusion across a membrane?
Resposta
A steeper gradient, larger surface area, higher temperature, shorter distance, and greater membrane permeability increase the rate.
Cartão 162
Pergunta
What is a mitochondrion?
Resposta
A double-membrane organelle where most aerobic ATP production occurs.
Cartão 163
Pergunta
What is a chloroplast?
Resposta
A double-membrane organelle where photosynthesis occurs in plants and algae.
Cartão 164
Pergunta
What is rough endoplasmic reticulum?
Resposta
A membrane network bearing ribosomes that synthesizes and begins processing many secreted and membrane proteins.
Cartão 165
Pergunta
What is smooth endoplasmic reticulum?
Resposta
A membrane network involved in lipid synthesis, detoxification, and calcium storage.
Cartão 166
Pergunta
Which term describes the main organelle of aerobic ATP production?
Resposta
a mitochondrion
Cartão 167
Pergunta
Which term describes the photosynthetic organelle of plants and algae?
Resposta
a chloroplast
Cartão 168
Pergunta
Which term describes the ribosome-studded membrane network?
Resposta
rough endoplasmic reticulum
Cartão 169
Pergunta
Which term describes the membrane network that lacks ribosomes and synthesizes lipids?
Resposta
smooth endoplasmic reticulum
Cartão 170
Pergunta
What is the Golgi apparatus?
Resposta
Stacked membranes that modify, sort, and package proteins and lipids into vesicles.
Cartão 171
Pergunta
What is a lysosome?
Resposta
An acidic enzyme-containing organelle that digests macromolecules and worn cellular components.
Cartão 172
Pergunta
What is a vesicle?
Resposta
A small membrane-bound compartment used for transport, storage, or chemical reactions.
Cartão 173
Pergunta
What is the central vacuole?
Resposta
A large plant-cell compartment that stores solutes and helps maintain turgor pressure.
Cartão 174
Pergunta
Which term describes the organelle that modifies and sorts cellular cargo?
Resposta
the Golgi apparatus
Cartão 175
Pergunta
Which term describes the acidic digestive organelle?
Resposta
a lysosome
Cartão 176
Pergunta
Which term describes a small membrane-bound transport compartment?
Resposta
a vesicle
Cartão 177
Pergunta
Which term describes the large plant compartment that supports turgor?
Resposta
the central vacuole
Cartão 178
Pergunta
Why can compartmentalization increase metabolic efficiency?
Resposta
It concentrates enzymes and substrates, maintains suitable local conditions, and separates incompatible reactions.
Cartão 179
Pergunta
How do mitochondrial cristae support ATP production?
Resposta
They increase inner-membrane area for electron transport chains and ATP synthase.
Cartão 180
Pergunta
Why are chloroplast thylakoids arranged as extensive membranes?
Resposta
They provide a large surface for light-absorbing complexes, electron transport chains, and ATP synthase.
Cartão 181
Pergunta
What is the main function of the nucleolus?
Resposta
It produces rRNA and assembles ribosomal subunits.
Cartão 182
Pergunta
Trace a secreted protein from synthesis to release.
Resposta
Ribosome on rough ER → ER lumen → transport vesicle → Golgi apparatus → secretory vesicle → plasma membrane → exocytosis.
Cartão 183
Pergunta
Why does a lysosome maintain an acidic interior?
Resposta
Its hydrolytic enzymes work best at low pH, and acidity helps confine their activity from the cytosol.
Cartão 184
Pergunta
How do the nucleus, ribosomes, ER, and Golgi cooperate in protein production?
Resposta
DNA instructions are transcribed in the nucleus; ribosomes translate them; ER folds or modifies many products; Golgi further modifies and sorts them.
Cartão 185
Pergunta
How are transport vesicles directed to the correct target membrane?
Resposta
Specific recognition proteins on vesicles and target membranes interact, allowing selective docking and fusion.
Cartão 186
Pergunta
What is cell differentiation?
Resposta
The process by which a cell develops specialized structure and function.
Cartão 187
Pergunta
What is a stem cell?
Resposta
An unspecialized cell able to self-renew and produce differentiated cells.
Cartão 188
Pergunta
What is gene expression?
Resposta
Use of genetic information to produce a functional RNA or protein product.
Cartão 189
Pergunta
What is a tissue?
Resposta
A coordinated group of similar or related cells performing a shared function.
Cartão 190
Pergunta
Which term describes development of specialized cell structure and function?
Resposta
cell differentiation
Cartão 191
Pergunta
Which term describes an unspecialized self-renewing cell?
Resposta
a stem cell
Cartão 192
Pergunta
Which term describes production of a functional product from genetic information?
Resposta
gene expression
Cartão 193
Pergunta
Which term describes a group of coordinated cells with a shared function?
Resposta
a tissue
Cartão 194
Pergunta
What is an organ?
Resposta
A structure made of multiple tissues working together for particular functions.
Cartão 195
Pergunta
What is the organ-system level of biological organization?
Resposta
A group of organs that coordinate to perform major functions for an organism.
Cartão 196
Pergunta
What is surface-area-to-volume ratio?
Resposta
The amount of surface area available relative to the volume it must serve.
Cartão 197
Pergunta
How can two specialized cells have the same genome but different structures?
Resposta
They express different sets and amounts of genes, producing different proteins and cellular features.
Cartão 198
Pergunta
Which term describes a structure composed of multiple tissue types?
Resposta
an organ
Cartão 199
Pergunta
Which term describes the level of biological organization formed by coordinated organs?
Resposta
an organ system
Cartão 200
Pergunta
Which term describes surface area available per unit volume?
Resposta
surface-area-to-volume ratio
Cartão 201
Pergunta
How is a mammalian red blood cell specialized for oxygen transport?
Resposta
Its biconcave shape increases exchange area, it is flexible, and loss of its nucleus leaves more space for hemoglobin.
Cartão 202
Pergunta
How is a sperm cell specialized for fertilization?
Resposta
It has a flagellum for movement, many mitochondria for ATP, a haploid nucleus, and an acrosome containing enzymes.
Cartão 203
Pergunta
How is a neuron specialized for rapid communication?
Resposta
Long processes carry signals over distance, branching dendrites receive inputs, and synaptic terminals transmit signals to other cells.
Cartão 204
Pergunta
How is a root hair cell specialized for mineral and water uptake?
Resposta
Its long projection increases surface area, its thin wall shortens the pathway, and membrane transport proteins take up ions.
Cartão 205
Pergunta
How is a palisade mesophyll cell specialized for photosynthesis?
Resposta
It contains many chloroplasts and is positioned near the upper leaf surface where light is strongest.
Cartão 206
Pergunta
How do ciliated epithelial cells help protect airways?
Resposta
Their cilia move mucus containing trapped particles and microbes toward the throat.
Cartão 207
Pergunta
Why can extreme specialization reduce a cell's independence?
Resposta
Resources and structures are committed to a narrow role, so the cell depends on other cells for functions it no longer performs well.
Cartão 208
Pergunta
What is water potential?
Resposta
The potential energy of water per unit volume relative to pure water, used to predict the direction of water movement.
Cartão 209
Pergunta
What is solute potential?
Resposta
The negative contribution of dissolved solutes to water potential.
Cartão 210
Pergunta
What is pressure potential?
Resposta
The contribution of physical pressure to water potential.
Cartão 211
Pergunta
What is turgor pressure?
Resposta
Outward pressure of a plant-cell interior against its cell wall after water uptake.
Cartão 212
Pergunta
Which term describes the tendency of water to move relative to pure water?
Resposta
water potential
Cartão 213
Pergunta
Which term describes the water-potential component lowered by dissolved solutes?
Resposta
solute potential
Cartão 214
Pergunta
Which term describes the water-potential component caused by physical pressure?
Resposta
pressure potential
Cartão 215
Pergunta
Which term describes pressure of plant-cell contents against the wall?
Resposta
turgor pressure
Cartão 216
Pergunta
What is plasmolysis?
Resposta
Separation of the plasma membrane from the cell wall after a plant cell loses water.
Cartão 217
Pergunta
What is a flaccid plant cell?
Resposta
A plant cell with insufficient turgor pressure to be firm.
Cartão 218
Pergunta
What is an isotonic condition?
Resposta
A condition in which two solutions have equal effective water potential and no net water movement occurs.
Cartão 219
Pergunta
In which direction does water move across a permeable membrane?
Resposta
From higher water potential to lower water potential.
Cartão 220
Pergunta
Which term describes membrane separation from the plant cell wall after water loss?
Resposta
plasmolysis
Cartão 221
Pergunta
Which term describes a plant cell lacking firm turgor?
Resposta
a flaccid plant cell
Cartão 222
Pergunta
Which term describes equal effective water potential across a membrane?
Resposta
an isotonic condition
Cartão 223
Pergunta
What is the water potential of pure water at standard pressure?
Resposta
Zero; adding solute makes water potential more negative.
Cartão 224
Pergunta
How are water potential, solute potential, and pressure potential related?
Resposta
Water potential equals solute potential plus pressure potential: Ψ = Ψs + Ψp.
Cartão 225
Pergunta
Why does a plant cell usually become turgid rather than burst in a hypotonic solution?
Resposta
Water entry raises pressure potential, while the rigid cell wall resists further expansion.
Cartão 226
Pergunta
What happens to a plant cell placed in a solution with much lower water potential?
Resposta
Water leaves the cell, turgor falls, and severe loss can cause plasmolysis.
Cartão 227
Pergunta
Can two solutions have different solute concentrations but equal water potential?
Resposta
Yes. A difference in pressure potential can offset a difference in solute potential.
Cartão 228
Pergunta
What is an enzyme?
Resposta
A biological catalyst that increases reaction rate without being consumed.
Cartão 229
Pergunta
What is an active site?
Resposta
The region of an enzyme where substrate binds and catalysis occurs.
Cartão 230
Pergunta
What is a substrate?
Resposta
A reactant molecule on which an enzyme acts.
Cartão 231
Pergunta
What is activation energy?
Resposta
The minimum energy input needed for a reaction to begin.
Cartão 232
Pergunta
Which term describes a biological catalyst?
Resposta
an enzyme
Cartão 233
Pergunta
Which term describes the substrate-binding catalytic region of an enzyme?
Resposta
an active site
Cartão 234
Pergunta
Which term describes a reactant bound and changed by an enzyme?
Resposta
a substrate
Cartão 235
Pergunta
Which term describes the energy barrier that must be overcome for a reaction?
Resposta
activation energy
Cartão 236
Pergunta
What is the induced-fit model?
Resposta
The model in which substrate binding changes active-site shape to improve catalytic interactions.
Cartão 237
Pergunta
What is enzyme denaturation?
Resposta
Loss of the active three-dimensional shape of an enzyme, usually causing loss of activity.
Cartão 238
Pergunta
What is competitive inhibition?
Resposta
Inhibition caused by a molecule competing with substrate for the active site.
Cartão 239
Pergunta
What is noncompetitive inhibition?
Resposta
Inhibition caused by binding away from the active site and reducing catalytic function.
Cartão 240
Pergunta
Which term describes the model where substrate binding reshapes the active site?
Resposta
the induced-fit model
Cartão 241
Pergunta
Which term describes loss of an enzyme's functional shape?
Resposta
enzyme denaturation
Cartão 242
Pergunta
Which term describes inhibition by active-site competition?
Resposta
competitive inhibition
Cartão 243
Pergunta
Which term describes inhibition by binding outside the active site?
Resposta
noncompetitive inhibition
Cartão 244
Pergunta
What is an enzyme optimum?
Resposta
The condition, such as temperature or pH, at which an enzyme's activity is highest.
Cartão 245
Pergunta
What is feedback inhibition?
Resposta
Control in which a pathway product inhibits an enzyme acting earlier in the pathway.
Cartão 246
Pergunta
How does an enzyme increase reaction rate?
Resposta
It stabilizes the transition state and provides a pathway with lower activation energy.
Cartão 247
Pergunta
Why does enzyme activity often rise and then fall as temperature increases?
Resposta
Molecular collisions initially increase, but excessive heat disrupts enzyme shape and denatures the active site.
Cartão 248
Pergunta
Which term describes the condition producing maximum enzyme activity?
Resposta
an enzyme optimum
Cartão 249
Pergunta
Which term describes pathway control by inhibition from an end product?
Resposta
feedback inhibition
Cartão 250
Pergunta
Why does each enzyme have a characteristic pH range?
Resposta
pH changes the ionization of amino-acid side chains, affecting active-site shape and chemical interactions.
Cartão 251
Pergunta
Why does increasing substrate concentration eventually stop increasing enzyme rate?
Resposta
At saturation, nearly all active sites are occupied and enzyme concentration limits the maximum rate.
Cartão 252
Pergunta
How does increasing enzyme concentration affect rate when substrate is abundant?
Resposta
More active sites are available, so the initial rate increases roughly in proportion to enzyme concentration.
Cartão 253
Pergunta
What gives an enzyme substrate specificity?
Resposta
The active site's shape, charge, polarity, and chemical groups complement particular substrates and transition states.
Cartão 254
Pergunta
What is one practical advantage of immobilizing an enzyme?
Resposta
The enzyme can be separated from products and reused while conditions around it are controlled.
Cartão 255
Pergunta
Does an enzyme change a reaction's equilibrium position?
Resposta
No. It speeds forward and reverse reactions but does not change the equilibrium constant or final equilibrium position.
Cartão 256
Pergunta
How can high substrate concentration reduce competitive inhibition?
Resposta
More substrate molecules increase the chance that substrate rather than inhibitor occupies the active site.
Cartão 257
Pergunta
Why are metabolic reactions commonly organized into pathways?
Resposta
A sequence of enzyme-controlled steps allows energy changes and intermediates to be controlled and coupled.
Cartão 258
Pergunta
What is ATP?
Resposta
A nucleotide that transfers usable energy through coupling of its hydrolysis to cellular processes.
Cartão 259
Pergunta
What is cellular respiration?
Resposta
Controlled release of energy from organic molecules to produce ATP.
Cartão 260
Pergunta
What is glycolysis?
Resposta
A cytosolic pathway that splits glucose into two pyruvate molecules and yields a small amount of ATP and reduced electron carriers.
Cartão 261
Pergunta
What is pyruvate?
Resposta
The three-carbon product of glycolysis that can enter aerobic or anaerobic pathways.
Cartão 262
Pergunta
Which term describes the cell's immediate phosphoryl-group energy carrier?
Resposta
ATP
Cartão 263
Pergunta
Which term describes controlled ATP-producing breakdown of organic molecules?
Resposta
cellular respiration
Cartão 264
Pergunta
Which term describes the cytosolic splitting of glucose into pyruvate?
Resposta
glycolysis
Cartão 265
Pergunta
Which term describes the three-carbon product of glycolysis?
Resposta
pyruvate
Cartão 266
Pergunta
What is aerobic respiration?
Resposta
Respiration that uses oxygen as the final electron acceptor and produces much more ATP than fermentation.
Cartão 267
Pergunta
What is anaerobic metabolism?
Resposta
ATP-producing metabolism that proceeds without oxygen.
Cartão 268
Pergunta
What is fermentation?
Resposta
An anaerobic pathway that regenerates oxidized electron carriers so glycolysis can continue.
Cartão 269
Pergunta
What is oxidation?
Resposta
Loss of electrons, often accompanied in biology by loss of hydrogen or gain of oxygen.
Cartão 270
Pergunta
Which term describes respiration using oxygen as final electron acceptor?
Resposta
aerobic respiration
Cartão 271
Pergunta
Which term describes ATP-producing metabolism without oxygen?
Resposta
anaerobic metabolism
Cartão 272
Pergunta
Which term describes anaerobic regeneration of electron carriers after glycolysis?
Resposta
fermentation
Cartão 273
Pergunta
Which term describes loss of electrons?
Resposta
oxidation
Cartão 274
Pergunta
What is reduction?
Resposta
Gain of electrons, often accompanied in biology by gain of hydrogen or loss of oxygen.
Cartão 275
Pergunta
What is a reduced electron carrier?
Resposta
A molecule such as NADH that carries high-energy electrons and hydrogen from one reaction to another.
Cartão 276
Pergunta
What is chemiosmosis?
Resposta
ATP production driven by ions moving down an electrochemical gradient through ATP synthase.
Cartão 277
Pergunta
What is the overall word equation for aerobic respiration of glucose?
Resposta
Glucose + oxygen → carbon dioxide + water + energy transferred to ATP and heat.
Cartão 278
Pergunta
Which term describes gain of electrons?
Resposta
reduction
Cartão 279
Pergunta
Which term describes a molecule carrying high-energy electrons between reactions?
Resposta
a reduced electron carrier
Cartão 280
Pergunta
Which term describes ATP production powered by an ion gradient?
Resposta
chemiosmosis
Cartão 281
Pergunta
Where does glycolysis occur?
Resposta
In the cytosol.
Cartão 282
Pergunta
What major stages of aerobic respiration occur in mitochondria?
Resposta
Pyruvate oxidation and the citric acid cycle occur in the matrix; electron transport and chemiosmosis occur at the inner membrane.
Cartão 283
Pergunta
What is oxygen's direct role in aerobic respiration?
Resposta
It accepts electrons and hydrogen ions at the end of the electron transport chain, forming water.
Cartão 284
Pergunta
Why does aerobic respiration yield much more ATP per glucose than fermentation?
Resposta
It transfers electrons through an electron transport chain and uses oxidative phosphorylation, extracting far more of glucose's energy.
Cartão 285
Pergunta
What is the purpose of lactate formation in oxygen-limited animal cells?
Resposta
It regenerates NAD⁺ so glycolysis can continue producing a small amount of ATP.
Cartão 286
Pergunta
What products are formed during alcoholic fermentation in yeast?
Resposta
Ethanol and carbon dioxide, while NAD⁺ is regenerated.
Cartão 287
Pergunta
Why is some energy released by respiration transferred as heat rather than captured in ATP?
Resposta
Energy conversions are not fully efficient, so part of the chemical energy becomes disordered molecular motion.
Cartão 288
Pergunta
What is substrate-level phosphorylation?
Resposta
Direct transfer of a phosphate group from a metabolic intermediate to ADP to form ATP.
Cartão 289
Pergunta
How does electron transport lead to ATP synthesis in mitochondria?
Resposta
Electron energy pumps protons across the inner membrane; proton flow back through ATP synthase drives ATP formation.
Cartão 290
Pergunta
Why can intense exercise increase lactate production?
Resposta
ATP demand can exceed oxygen delivery and aerobic capacity, so cells regenerate NAD⁺ through lactate formation to sustain glycolysis.
Cartão 291
Pergunta
What is photosynthesis?
Resposta
Conversion of light energy into chemical energy used to synthesize organic molecules from carbon dioxide.
Cartão 292
Pergunta
What is chlorophyll?
Resposta
A green pigment that absorbs light energy for photosynthesis.
Cartão 293
Pergunta
What is an absorption spectrum?
Resposta
A graph showing how strongly a pigment absorbs different wavelengths of light.
Cartão 294
Pergunta
What is an action spectrum?
Resposta
A graph showing the rate or effectiveness of photosynthesis at different wavelengths.
Cartão 295
Pergunta
Which term describes light-driven synthesis of organic molecules from carbon dioxide?
Resposta
photosynthesis
Cartão 296
Pergunta
Which term describes the principal green photosynthetic pigment?
Resposta
chlorophyll
Cartão 297
Pergunta
Which term describes a graph of pigment absorption versus wavelength?
Resposta
an absorption spectrum
Cartão 298
Pergunta
Which term describes a graph of photosynthetic effectiveness versus wavelength?
Resposta
an action spectrum
Cartão 299
Pergunta
What is photolysis of water?
Resposta
Light-driven splitting of water that supplies electrons and hydrogen ions and releases oxygen.
Cartão 300
Pergunta
What are light-dependent reactions?
Resposta
Photosynthetic reactions that use light to generate ATP and reduced electron carriers while releasing oxygen.
Cartão 301
Pergunta
What is the Calvin cycle?
Resposta
A set of chloroplast reactions that uses ATP and reduced electron carriers to convert carbon dioxide into carbohydrate precursors.
Cartão 302
Pergunta
What is carbon fixation?
Resposta
Incorporation of inorganic carbon dioxide into an organic molecule.
Cartão 303
Pergunta
Which term describes light-driven splitting of water?
Resposta
photolysis of water
Cartão 304
Pergunta
Which term describes photosynthetic reactions that directly capture light energy?
Resposta
light-dependent reactions
Cartão 305
Pergunta
Which term describes the carbon-reduction cycle of photosynthesis?
Resposta
the Calvin cycle
Cartão 306
Pergunta
Which term describes incorporation of carbon dioxide into organic matter?
Resposta
carbon fixation
Cartão 307
Pergunta
What is the role of a stoma in photosynthesis?
Resposta
A pore in the leaf epidermis that regulates carbon-dioxide entry as well as water loss.
Cartão 308
Pergunta
What is a limiting factor of photosynthesis?
Resposta
The environmental factor whose availability currently restricts the photosynthetic rate.
Cartão 309
Pergunta
What is the light compensation point?
Resposta
The light intensity at which photosynthetic carbon uptake equals respiratory carbon release.
Cartão 310
Pergunta
What is the overall word equation for oxygenic photosynthesis?
Resposta
Carbon dioxide + water → carbohydrate + oxygen, using light energy.
Cartão 311
Pergunta
Which term describes the regulated leaf pore controlling carbon-dioxide entry for photosynthesis?
Resposta
a stoma
Cartão 312
Pergunta
Which term describes the factor currently restricting photosynthetic rate?
Resposta
a limiting factor
Cartão 313
Pergunta
Which term describes the light level where photosynthesis and respiration balance?
Resposta
the light compensation point
Cartão 314
Pergunta
Where do the main stages of photosynthesis occur in a chloroplast?
Resposta
Light-dependent reactions occur in thylakoid membranes; carbon-fixation reactions occur in the stroma.
Cartão 315
Pergunta
What energy conversion occurs during photosynthesis?
Resposta
Light energy is converted into chemical energy stored first in ATP and reduced carriers and ultimately in organic molecules.
Cartão 316
Pergunta
From which reactant does the oxygen released by photosynthesis originate?
Resposta
Water.
Cartão 317
Pergunta
What role does RuBisCO play in photosynthesis?
Resposta
It catalyzes fixation of carbon dioxide by adding it to an organic acceptor molecule.
Cartão 318
Pergunta
What tradeoff is controlled when stomata open?
Resposta
Opening permits carbon dioxide entry but increases water loss by transpiration.
Cartão 319
Pergunta
Name three leaf features that support photosynthesis.
Resposta
A broad surface captures light, a thin structure shortens diffusion paths, and veins supply water and remove sugars; chloroplast-rich cells and stomata also help.
Cartão 320
Pergunta
What can a plant do with carbohydrate made by photosynthesis?
Resposta
Use it in respiration, convert it to storage or structural carbohydrates, or use its carbon to make lipids, amino acids, and other molecules.
Cartão 321
Pergunta
How are products of the light-dependent reactions used in carbon fixation?
Resposta
ATP supplies energy and NADPH supplies reducing power for conversion of fixed carbon into carbohydrate precursors.
Cartão 322
Pergunta
Why does increasing light intensity eventually stop increasing photosynthetic rate?
Resposta
Another factor, such as carbon dioxide supply, temperature, or biochemical capacity, becomes limiting.
Cartão 323
Pergunta
How can increasing carbon dioxide concentration affect photosynthetic rate?
Resposta
It can increase the rate until another factor becomes limiting.
Cartão 324
Pergunta
Why does photosynthetic rate usually have a temperature optimum?
Resposta
Enzyme-controlled reactions accelerate with temperature up to an optimum, then decline as enzymes and membranes lose effective function.
Cartão 325
Pergunta
Why does an action spectrum broadly resemble the combined absorption spectra of photosynthetic pigments?
Resposta
Wavelengths absorbed by the pigments supply more energy for photosynthesis than poorly absorbed wavelengths.
Cartão 326
Pergunta
What is semiconservative replication?
Resposta
DNA replication in which each daughter molecule contains one parental strand and one newly synthesized strand.
Cartão 327
Pergunta
What is DNA helicase?
Resposta
An enzyme that unwinds the double helix and separates the strands by disrupting base pairing.
Cartão 328
Pergunta
What is DNA polymerase?
Resposta
An enzyme that adds nucleotides to a growing DNA strand using a template.
Cartão 329
Pergunta
What is a primer?
Resposta
A short nucleic-acid segment providing a free 3′ end from which DNA polymerase can extend.
Cartão 330
Pergunta
Which term describes replication producing one old and one new strand per DNA molecule?
Resposta
semiconservative replication
Cartão 331
Pergunta
Which term describes the enzyme that separates DNA strands?
Resposta
DNA helicase
Cartão 332
Pergunta
Which term describes the enzyme that builds DNA from a template?
Resposta
DNA polymerase
Cartão 333
Pergunta
Which term describes the short segment providing a starting 3′ end?
Resposta
a primer
Cartão 334
Pergunta
What is the leading strand?
Resposta
The new DNA strand synthesized continuously toward the replication fork.
Cartão 335
Pergunta
What is the lagging strand?
Resposta
The new DNA strand synthesized discontinuously away from the replication fork.
Cartão 336
Pergunta
What is an Okazaki fragment?
Resposta
A short DNA segment synthesized on the lagging strand.
Cartão 337
Pergunta
What is DNA ligase?
Resposta
An enzyme that seals breaks in the sugar-phosphate backbone, joining DNA fragments.
Cartão 338
Pergunta
Which term describes the continuously synthesized daughter strand?
Resposta
the leading strand
Cartão 339
Pergunta
Which term describes the discontinuously synthesized daughter strand?
Resposta
the lagging strand
Cartão 340
Pergunta
Which term describes a short newly made segment of lagging-strand DNA?
Resposta
an Okazaki fragment
Cartão 341
Pergunta
Which term describes the enzyme that joins DNA fragments by sealing the backbone?
Resposta
DNA ligase
Cartão 342
Pergunta
How does complementary base pairing ensure accurate DNA copying?
Resposta
Each template base specifies the nucleotide added opposite it: A pairs with T, and C pairs with G.
Cartão 343
Pergunta
Why does DNA polymerase synthesize DNA only 5′ to 3′?
Resposta
It can add a nucleotide only to the free 3′ hydroxyl group of the growing strand.
Cartão 344
Pergunta
When in the cell cycle is nuclear DNA replicated?
Resposta
During S phase of interphase, before cell division.
Cartão 345
Pergunta
How can a replication error become a permanent mutation?
Resposta
If it escapes proofreading and repair, the altered sequence can be copied in later cell generations.
Cartão 346
Pergunta
Why are leading and lagging strands synthesized differently?
Resposta
The templates are antiparallel while DNA polymerase works only 5′ to 3′, forcing one strand to be made discontinuously.
Cartão 347
Pergunta
How do proofreading and repair reduce replication errors?
Resposta
Incorrectly paired nucleotides are recognized, removed, and replaced before or after replication continues.
Cartão 348
Pergunta
What three repeating steps amplify DNA in PCR?
Resposta
Strand separation by heating, primer annealing during cooling, and DNA extension by a heat-stable polymerase.
Cartão 349
Pergunta
What determines which DNA region PCR amplifies?
Resposta
The sequences and positions of the two primers flanking the target region.
Cartão 350
Pergunta
What is transcription?
Resposta
Synthesis of RNA from a DNA template.
Cartão 351
Pergunta
What is RNA polymerase?
Resposta
The enzyme that synthesizes RNA complementary to a DNA template strand.
Cartão 352
Pergunta
What is messenger RNA?
Resposta
RNA carrying a coding sequence from DNA to ribosomes.
Cartão 353
Pergunta
What is a codon?
Resposta
A three-base sequence in mRNA that specifies an amino acid or a translation signal.
Cartão 354
Pergunta
Which term describes RNA synthesis from DNA?
Resposta
transcription
Cartão 355
Pergunta
Which term describes the enzyme that builds RNA from a DNA template?
Resposta
RNA polymerase
Cartão 356
Pergunta
Which term describes RNA that carries coding information to ribosomes?
Resposta
messenger RNA
Cartão 357
Pergunta
Which term describes a three-base mRNA unit?
Resposta
a codon
Cartão 358
Pergunta
What is translation?
Resposta
Synthesis of a polypeptide using the codon sequence of mRNA.
Cartão 359
Pergunta
What does a ribosome do during translation?
Resposta
It reads mRNA and catalyzes polypeptide synthesis using its rRNA-protein machinery.
Cartão 360
Pergunta
What is transfer RNA?
Resposta
RNA that carries a specific amino acid and pairs its anticodon with an mRNA codon.
Cartão 361
Pergunta
What is an anticodon?
Resposta
A three-base tRNA sequence complementary to an mRNA codon.
Cartão 362
Pergunta
Which term describes polypeptide synthesis from an mRNA sequence?
Resposta
translation
Cartão 363
Pergunta
Which term describes the translation complex that reads mRNA and builds a polypeptide?
Resposta
a ribosome
Cartão 364
Pergunta
Which term describes the adaptor RNA carrying an amino acid?
Resposta
transfer RNA
Cartão 365
Pergunta
Which term describes the tRNA triplet that pairs with a codon?
Resposta
an anticodon
Cartão 366
Pergunta
What is the genetic code?
Resposta
The set of rules relating mRNA codons to amino acids and translation signals.
Cartão 367
Pergunta
What are start and stop codons?
Resposta
mRNA signals that establish the reading frame or terminate translation.
Cartão 368
Pergunta
Where do transcription and translation occur in a eukaryotic cell?
Resposta
Transcription occurs in the nucleus; translation occurs on ribosomes in the cytoplasm or on rough ER.
Cartão 369
Pergunta
How is an mRNA sequence related to its DNA template strand?
Resposta
It is complementary and antiparallel, with uracil in RNA opposite adenine in DNA.
Cartão 370
Pergunta
Which term describes the codon-to-amino-acid rule set?
Resposta
the genetic code
Cartão 371
Pergunta
Which term describes codons that begin or end translation?
Resposta
start and stop codons
Cartão 372
Pergunta
What reaction does the ribosome catalyze as a polypeptide grows?
Resposta
Formation of peptide bonds between adjacent amino acids.
Cartão 373
Pergunta
What does it mean that the genetic code is degenerate?
Resposta
Most amino acids are specified by more than one codon.
Cartão 374
Pergunta
How can one mRNA produce many polypeptides quickly?
Resposta
Multiple ribosomes can translate the same mRNA simultaneously as a polyribosome.
Cartão 375
Pergunta
Why is translation not the final step in producing many functional proteins?
Resposta
The polypeptide must fold and may undergo cleavage, chemical modification, or assembly with other subunits.
Cartão 376
Pergunta
How does mRNA compare with the DNA coding strand?
Resposta
It has the same base sequence except that RNA contains uracil where DNA contains thymine.
Cartão 377
Pergunta
What happens during eukaryotic RNA splicing?
Resposta
Introns are removed and exons are joined to form mature mRNA.
Cartão 378
Pergunta
Why must codons be read in the correct reading frame?
Resposta
Changing the starting position changes every downstream triplet and therefore the amino-acid sequence.
Cartão 379
Pergunta
How is the correct amino acid matched to each mRNA codon?
Resposta
Each tRNA is charged with a particular amino acid, and its anticodon pairs with the complementary codon.
Cartão 380
Pergunta
How can a base substitution affect a protein?
Resposta
It may be silent, change one amino acid, create a stop codon, or sometimes alter RNA processing.
Cartão 381
Pergunta
What is a mutation?
Resposta
A change in a DNA sequence or chromosome structure that can be passed to daughter cells.
Cartão 382
Pergunta
What is a base substitution?
Resposta
Replacement of one nucleotide pair by another.
Cartão 383
Pergunta
What is an insertion mutation?
Resposta
Addition of one or more nucleotides to a DNA sequence.
Cartão 384
Pergunta
What is a deletion mutation?
Resposta
Loss of one or more nucleotides from a DNA sequence.
Cartão 385
Pergunta
Which term describes a lasting DNA-sequence or chromosome change?
Resposta
a mutation
Cartão 386
Pergunta
Which term describes replacement of one DNA base pair?
Resposta
a base substitution
Cartão 387
Pergunta
Which term describes addition of nucleotides to DNA?
Resposta
an insertion mutation
Cartão 388
Pergunta
Which term describes loss of nucleotides from DNA?
Resposta
a deletion mutation
Cartão 389
Pergunta
What is a frameshift mutation?
Resposta
A coding-sequence insertion or deletion not divisible by three that changes downstream codon grouping.
Cartão 390
Pergunta
What is a silent mutation?
Resposta
A sequence change that does not alter the encoded amino acid.
Cartão 391
Pergunta
What is a missense mutation?
Resposta
A mutation that changes a codon so a different amino acid is incorporated.
Cartão 392
Pergunta
What is a nonsense mutation?
Resposta
A mutation that changes an amino-acid codon into a stop codon.
Cartão 393
Pergunta
Which term describes a mutation that shifts downstream codon grouping?
Resposta
a frameshift mutation
Cartão 394
Pergunta
Which term describes a coding change that leaves the amino acid unchanged?
Resposta
a silent mutation
Cartão 395
Pergunta
Which term describes a mutation causing one amino-acid substitution?
Resposta
a missense mutation
Cartão 396
Pergunta
Which term describes a mutation creating a premature stop codon?
Resposta
a nonsense mutation
Cartão 397
Pergunta
How do germline and somatic mutations differ in inheritance?
Resposta
Germline mutations can enter gametes and be inherited; somatic mutations affect a cell lineage within the individual.
Cartão 398
Pergunta
What can cause mutations?
Resposta
Replication errors, spontaneous chemical changes, radiation, and mutagenic chemicals can alter DNA.
Cartão 399
Pergunta
How does DNA repair protect genome stability?
Resposta
Repair systems detect damaged or mismatched DNA and restore the correct structure or sequence when possible.
Cartão 400
Pergunta
Why are mutations essential to evolution despite often being neutral or harmful?
Resposta
They create new alleles, providing the heritable variation on which selection and drift act.
Cartão 401
Pergunta
What is the basic role of guide RNA in CRISPR gene editing?
Resposta
It directs a nuclease to a complementary DNA sequence.
Cartão 402
Pergunta
Why can the same type of DNA mutation have effects ranging from none to severe?
Resposta
Effects depend on location, genetic-code redundancy, protein role, cell type, and environmental context.
Cartão 403
Pergunta
How can accumulated mutations contribute to cancer?
Resposta
Mutations can activate growth-promoting genes or disable genes that restrain division, repair DNA, or trigger cell death.
Cartão 404
Pergunta
Why can repairing a CRISPR-induced DNA break produce different editing outcomes?
Resposta
Different cellular repair pathways may disrupt the target sequence or use a supplied template for a specific change.
Cartão 405
Pergunta
What is an off-target effect in gene editing?
Resposta
An unintended DNA change at a site sufficiently similar to the intended target.
Cartão 406
Pergunta
Why does heritable human genome editing raise additional ethical concerns?
Resposta
Changes could pass to future generations who cannot consent, with uncertain long-term biological and social effects.
Cartão 407
Pergunta
What is the cell cycle?
Resposta
The ordered sequence of cell growth, DNA replication, nuclear division, and cell division.
Cartão 408
Pergunta
What is interphase?
Resposta
The period of growth, normal activity, and DNA replication between nuclear divisions.
Cartão 409
Pergunta
What is mitosis?
Resposta
Nuclear division that usually produces genetically equivalent daughter nuclei.
Cartão 410
Pergunta
What is cytokinesis?
Resposta
Division of the cytoplasm to form separate daughter cells.
Cartão 411
Pergunta
Which term describes the ordered sequence from one cell division to the next?
Resposta
the cell cycle
Cartão 412
Pergunta
Which term describes the growth and DNA-replication period between divisions?
Resposta
interphase
Cartão 413
Pergunta
Which term describes division producing genetically equivalent nuclei?
Resposta
mitosis
Cartão 414
Pergunta
Which term describes physical division of the cytoplasm?
Resposta
cytokinesis
Cartão 415
Pergunta
What is a chromosome?
Resposta
One DNA molecule packaged with associated proteins.
Cartão 416
Pergunta
What are sister chromatids?
Resposta
The two replicated copies of a chromosome joined before separation.
Cartão 417
Pergunta
What is a centromere?
Resposta
The chromosome region that holds sister chromatids together and organizes kinetochore attachment.
Cartão 418
Pergunta
What is the mitotic spindle?
Resposta
A microtubule system that attaches to and separates chromosomes during cell division.
Cartão 419
Pergunta
Which term describes a protein-packaged DNA molecule?
Resposta
a chromosome
Cartão 420
Pergunta
Which term describes joined replicated copies of one chromosome?
Resposta
sister chromatids
Cartão 421
Pergunta
Which term describes the chromosome region joining sister chromatids?
Resposta
a centromere
Cartão 422
Pergunta
Which term describes the chromosome-separating microtubule system?
Resposta
the mitotic spindle
Cartão 423
Pergunta
What is the basic sequence of mitosis?
Resposta
Chromosomes condense, align at the cell equator, sister chromatids separate to opposite poles, and new nuclei form.
Cartão 424
Pergunta
Why must DNA replicate before mitosis?
Resposta
Each chromosome must have two copies so each daughter nucleus can receive a complete genome.
Cartão 425
Pergunta
Why are daughter cells from mitosis usually genetically similar?
Resposta
Replicated sister chromatids are separated so each daughter receives one copy of every chromosome.
Cartão 426
Pergunta
What are major roles of mitosis in multicellular organisms?
Resposta
Growth, tissue repair, cell replacement, and some forms of asexual reproduction.
Cartão 427
Pergunta
How do homologous chromosomes differ from sister chromatids?
Resposta
Homologs carry the same gene loci but may have different alleles; sister chromatids are replicated copies of one chromosome.
Cartão 428
Pergunta
What key outcome distinguishes mitosis from meiosis?
Resposta
Mitosis usually preserves chromosome number and similarity; meiosis halves chromosome number and generates genetically varied haploid cells.
Cartão 429
Pergunta
How does cytokinesis commonly occur in animal cells?
Resposta
A contractile ring tightens the plasma membrane into a cleavage furrow.
Cartão 430
Pergunta
How does cytokinesis commonly occur in plant cells?
Resposta
Vesicles fuse at the center to form a cell plate that develops into new membranes and a cell wall.
Cartão 431
Pergunta
What is the purpose of cell-cycle checkpoints?
Resposta
They delay progression when conditions are unsuitable or DNA and chromosome attachment are defective.
Cartão 432
Pergunta
How is loss of cell-cycle control related to cancer?
Resposta
Cells can divide despite damage or growth restraints, producing an expanding abnormal clone.
Cartão 433
Pergunta
What is a gene?
Resposta
A DNA sequence that contributes to a functional product and influences a characteristic or cellular process.
Cartão 434
Pergunta
What is an allele?
Resposta
One of the alternative DNA-sequence forms at a gene locus.
Cartão 435
Pergunta
What is a gene locus?
Resposta
The physical position of a gene on a chromosome.
Cartão 436
Pergunta
What is a genotype?
Resposta
The allele combination of an organism at one or more loci.
Cartão 437
Pergunta
Which term describes a functional DNA sequence?
Resposta
a gene
Cartão 438
Pergunta
Which term describes an alternative form of a gene?
Resposta
an allele
Cartão 439
Pergunta
Which term describes a gene's chromosome position?
Resposta
a gene locus
Cartão 440
Pergunta
Which term describes an organism's allele combination?
Resposta
a genotype
Cartão 441
Pergunta
What is a phenotype?
Resposta
An observable or measurable trait produced by genotype and environment.
Cartão 442
Pergunta
What is homozygous?
Resposta
Having two identical alleles at a diploid locus.
Cartão 443
Pergunta
What is heterozygous?
Resposta
Having two different alleles at a diploid locus.
Cartão 444
Pergunta
What is a dominant allele?
Resposta
An allele expressed in the phenotype of a heterozygote under a specified inheritance model.
Cartão 445
Pergunta
Which term describes an observable trait resulting from genes and environment?
Resposta
a phenotype
Cartão 446
Pergunta
Which term describes having two identical alleles at a locus?
Resposta
homozygous
Cartão 447
Pergunta
Which term describes having two different alleles at a locus?
Resposta
heterozygous
Cartão 448
Pergunta
Which term describes an allele expressed in a heterozygote?
Resposta
a dominant allele
Cartão 449
Pergunta
What is a recessive allele?
Resposta
An allele whose phenotype is masked by a dominant allele in a heterozygote.
Cartão 450
Pergunta
What is a genetic carrier?
Resposta
An unaffected heterozygote who can transmit a recessive disease allele.
Cartão 451
Pergunta
What is a test cross?
Resposta
A cross with a homozygous recessive individual used to infer an unknown dominant phenotype's genotype.
Cartão 452
Pergunta
What is a pedigree?
Resposta
A diagram showing biological relationships and occurrence of a trait across generations.
Cartão 453
Pergunta
Which term describes an allele masked in a heterozygote?
Resposta
a recessive allele
Cartão 454
Pergunta
Which term describes an unaffected heterozygote carrying a recessive disease allele?
Resposta
a genetic carrier
Cartão 455
Pergunta
Which term describes a cross used to reveal an unknown dominant genotype?
Resposta
a test cross
Cartão 456
Pergunta
Which term describes a family diagram tracking a trait across generations?
Resposta
a pedigree
Cartão 457
Pergunta
What does allele segregation mean during gamete formation?
Resposta
The two alleles at a diploid locus separate so each gamete receives one.
Cartão 458
Pergunta
What does a Punnett square predict?
Resposta
Expected genotype and phenotype probabilities from specified parental gametes, not guaranteed family outcomes.
Cartão 459
Pergunta
What phenotypic ratio is expected from Aa × Aa with complete dominance?
Resposta
Approximately 3 dominant phenotype : 1 recessive phenotype.
Cartão 460
Pergunta
What genotypic ratio is expected from Aa × Aa?
Resposta
1 AA : 2 Aa : 1 aa.
Cartão 461
Pergunta
What happens in codominance?
Resposta
Both alleles contribute distinctly to the heterozygous phenotype.
Cartão 462
Pergunta
What happens in incomplete dominance?
Resposta
The heterozygote has a phenotype intermediate between the two homozygotes.
Cartão 463
Pergunta
How can environment affect phenotype without changing genotype?
Resposta
Conditions alter development, physiology, or gene expression, changing the observed trait.
Cartão 464
Pergunta
What is the ultimate source of new alleles?
Resposta
Mutation.
Cartão 465
Pergunta
Why are X-linked recessive traits more common in XY individuals?
Resposta
They have only one X chromosome, so one recessive allele on it can determine the phenotype.
Cartão 466
Pergunta
When is the product rule used in genetic probability?
Resposta
For independent events that must both occur; multiply their probabilities.
Cartão 467
Pergunta
When is the sum rule used in genetic probability?
Resposta
For mutually exclusive alternative outcomes; add their probabilities.
Cartão 468
Pergunta
Why do polygenic traits often show continuous variation?
Resposta
Many loci contribute small effects, creating many possible genotypes and phenotypes, often further influenced by environment.
Cartão 469
Pergunta
What pedigree pattern can suggest an autosomal recessive trait?
Resposta
Unaffected parents can have affected children, and all sexes are affected at similar frequencies.
Cartão 470
Pergunta
What is a species?
Resposta
A group of organisms whose members can potentially interbreed and produce fertile offspring under natural conditions.
Cartão 471
Pergunta
What is binomial nomenclature?
Resposta
The two-part scientific naming system using a genus name followed by a specific epithet.
Cartão 472
Pergunta
What is taxonomy?
Resposta
The naming and classification of organisms.
Cartão 473
Pergunta
What is a biological domain?
Resposta
The broadest commonly used taxonomic rank, separating Bacteria, Archaea, and Eukarya.
Cartão 474
Pergunta
Which term describes a naturally interbreeding group producing fertile offspring?
Resposta
a species
Cartão 475
Pergunta
Which term describes the genus-plus-specific-epithet naming system?
Resposta
binomial nomenclature
Cartão 476
Pergunta
Which term describes the science of naming and classifying organisms?
Resposta
taxonomy
Cartão 477
Pergunta
Which term describes the broadest common taxonomic rank?
Resposta
a biological domain
Cartão 478
Pergunta
What is biodiversity?
Resposta
Variation of life at genetic, species, and ecosystem levels.
Cartão 479
Pergunta
What is an autotroph?
Resposta
An organism that makes organic compounds from inorganic carbon using light or chemical energy.
Cartão 480
Pergunta
What is a heterotroph?
Resposta
An organism that obtains organic carbon by consuming other organisms or their products.
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Cartão 481
Pergunta
What is a unicellular organism?
Resposta
An organism consisting of one cell that carries out all essential life functions.
Cartão 482
Pergunta
Which term describes variation of life across genes, species, and ecosystems?
Resposta
biodiversity
Cartão 483
Pergunta
Which term describes an organism that builds organic matter from inorganic carbon?
Resposta
an autotroph
Cartão 484
Pergunta
Which term describes an organism obtaining organic carbon from other organisms?
Resposta
a heterotroph
Cartão 485
Pergunta
Which term describes an organism made of one cell?
Resposta
a unicellular organism
Cartão 486
Pergunta
What is a multicellular organism?
Resposta
An organism composed of many cooperating cells, often with specialized cell types.
Cartão 487
Pergunta
What is a karyotype?
Resposta
An ordered display of chromosomes used to examine their number and large-scale structure.
Cartão 488
Pergunta
What broad feature distinguishes both Bacteria and Archaea from Eukarya?
Resposta
Their cells lack a nucleus and other membrane-bound organelles.
Cartão 489
Pergunta
What features characterize most plant cells?
Resposta
Cellulose walls, chloroplasts in photosynthetic tissues, and large vacuoles are typical features.
Cartão 490
Pergunta
Which term describes an organism made of many cooperating cells?
Resposta
a multicellular organism
Cartão 491
Pergunta
Which term describes an ordered display of an individual's chromosomes?
Resposta
a karyotype
Cartão 492
Pergunta
How do fungi obtain nutrients?
Resposta
They secrete digestive enzymes and absorb soluble products; their cells usually have chitin-containing walls.
Cartão 493
Pergunta
What distinguishes animal nutrition and cell structure?
Resposta
Animals ingest organic material, and their cells lack cell walls and chloroplasts.
Cartão 494
Pergunta
Why are scientific names useful across languages?
Resposta
A standardized name identifies the same organism internationally and reduces ambiguity from local common names.
Cartão 495
Pergunta
Why can genetic diversity improve a population's resilience?
Resposta
More heritable variation increases the chance that some individuals tolerate new diseases or environmental changes.
Cartão 496
Pergunta
What does ecosystem diversity measure?
Resposta
The variety of habitats, communities, and ecological processes within a region.
Cartão 497
Pergunta
Why are Archaea classified separately from Bacteria?
Resposta
They differ in genetic sequences, membrane chemistry, cell-wall composition, and aspects of molecular machinery.
Cartão 498
Pergunta
Why is the biological species concept difficult to apply to fossils or asexual organisms?
Resposta
Their ability to interbreed and produce fertile offspring cannot be tested in the usual way.
Cartão 499
Pergunta
Does a larger chromosome number necessarily mean a more complex organism?
Resposta
No. Chromosome number varies through fusion, fission, and duplication and does not directly measure biological complexity.
Cartão 500
Pergunta
Does genome size reliably predict organismal complexity?
Resposta
No. Large amounts of noncoding and repeated DNA make genome size a poor simple measure of complexity.
Cartão 501
Pergunta
What evidence can be combined when classifying organisms?
Resposta
Molecular sequences, cell structure, anatomy, development, physiology, and reproductive evidence can all contribute.
Cartão 502
Pergunta
What is gas exchange?
Resposta
Diffusion of respiratory gases between an organism and its environment or transport fluid.
Cartão 503
Pergunta
What is ventilation?
Resposta
Bulk movement of air or water over a gas-exchange surface.
Cartão 504
Pergunta
What is an alveolus?
Resposta
A microscopic air sac in the lung where gases diffuse between air and blood.
Cartão 505
Pergunta
What is pulmonary surfactant?
Resposta
A substance lining alveoli that lowers surface tension and reduces collapse.
Cartão 506
Pergunta
Which term describes diffusion of oxygen and carbon dioxide across a respiratory surface?
Resposta
gas exchange
Cartão 507
Pergunta
Which term describes bulk movement of respiratory medium over an exchange surface?
Resposta
ventilation
Cartão 508
Pergunta
Which term describes a microscopic lung air sac?
Resposta
an alveolus
Cartão 509
Pergunta
Which term describes the alveolar lining that lowers surface tension?
Resposta
pulmonary surfactant
Cartão 510
Pergunta
What is the diaphragm?
Resposta
A sheet of skeletal muscle whose contraction increases thoracic volume during inhalation.
Cartão 511
Pergunta
What is tidal volume?
Resposta
The volume of air moved in or out during a normal breath.
Cartão 512
Pergunta
What is a stoma?
Resposta
A regulated epidermal pore through which gases diffuse in leaves.
Cartão 513
Pergunta
What is countercurrent exchange?
Resposta
Exchange between fluids moving in opposite directions, maintaining a gradient along most of the surface.
Cartão 514
Pergunta
Which term describes the muscle sheet that expands the thorax during inhalation?
Resposta
the diaphragm
Cartão 515
Pergunta
Which term describes air volume moved in one normal breath?
Resposta
tidal volume
Cartão 516
Pergunta
Which term describes a regulated leaf gas-exchange pore?
Resposta
a stoma
Cartão 517
Pergunta
Which term describes opposite fluid flow that maintains an exchange gradient?
Resposta
countercurrent exchange
Cartão 518
Pergunta
What features make an efficient gas-exchange surface?
Resposta
Large area, short diffusion distance, permeability, and maintained concentration gradients.
Cartão 519
Pergunta
How is a steep oxygen gradient maintained across alveoli?
Resposta
Ventilation replenishes alveolar oxygen and blood flow removes absorbed oxygen.
Cartão 520
Pergunta
How does diaphragm contraction cause inhalation?
Resposta
Thoracic volume increases, lung pressure falls below atmospheric pressure, and air flows inward.
Cartão 521
Pergunta
What drives quiet exhalation?
Resposta
The diaphragm relaxes and elastic recoil reduces thoracic and lung volume, raising pressure and pushing air out.
Cartão 522
Pergunta
Why do ventilation rate and depth increase during exercise?
Resposta
They increase oxygen uptake and carbon dioxide removal to support higher cellular respiration.
Cartão 523
Pergunta
How does leaf structure shorten the pathway for carbon dioxide diffusion?
Resposta
Stomata open into air spaces, and mesophyll cells expose moist surfaces close to those spaces.
Cartão 524
Pergunta
Why does carbon dioxide diffuse from tissues into blood?
Resposta
Respiring cells produce carbon dioxide, making its partial pressure higher in tissues than in incoming blood.
Cartão 525
Pergunta
How does countercurrent flow improve oxygen uptake at fish gills?
Resposta
Blood continually meets water with a higher oxygen concentration, preserving diffusion along the lamella.
Cartão 526
Pergunta
Why does closing stomata reduce both water loss and photosynthesis?
Resposta
It limits water-vapor diffusion out but also restricts carbon dioxide diffusion into the leaf.
Cartão 527
Pergunta
What is a circulatory system?
Resposta
A transport system that moves a fluid carrying gases, nutrients, wastes, hormones, and heat through an organism.
Cartão 528
Pergunta
What is an artery?
Resposta
A blood vessel carrying blood away from the heart under relatively high pressure.
Cartão 529
Pergunta
What is a vein?
Resposta
A blood vessel carrying blood toward the heart, usually with low pressure and often valves.
Cartão 530
Pergunta
What is a capillary?
Resposta
A microscopic thin-walled vessel where substances exchange between blood and tissues.
Cartão 531
Pergunta
Which term describes an internal fluid-transport system?
Resposta
a circulatory system
Cartão 532
Pergunta
Which term describes a vessel carrying blood away from the heart?
Resposta
an artery
Cartão 533
Pergunta
Which term describes a vessel carrying blood toward the heart?
Resposta
a vein
Cartão 534
Pergunta
Which term describes a microscopic exchange blood vessel?
Resposta
a capillary
Cartão 535
Pergunta
What is the cardiac cycle?
Resposta
The repeating sequence of heart-chamber contraction and relaxation that pumps blood.
Cartão 536
Pergunta
What is hemoglobin?
Resposta
An iron-containing protein in red blood cells that binds oxygen reversibly.
Cartão 537
Pergunta
What is xylem?
Resposta
Plant vascular tissue that transports water and mineral ions and provides structural support.
Cartão 538
Pergunta
What is phloem?
Resposta
Plant vascular tissue that transports sucrose and other organic solutes between sources and sinks.
Cartão 539
Pergunta
Which term describes the repeating pumping sequence of the heart?
Resposta
the cardiac cycle
Cartão 540
Pergunta
Which term describes the oxygen-carrying protein of red blood cells?
Resposta
hemoglobin
Cartão 541
Pergunta
Which term describes plant tissue carrying water and minerals?
Resposta
xylem
Cartão 542
Pergunta
Which term describes plant tissue carrying organic solutes?
Resposta
phloem
Cartão 543
Pergunta
What is transpiration?
Resposta
Loss of water vapor from plant surfaces, mainly through stomata.
Cartão 544
Pergunta
What is phloem translocation?
Resposta
Movement of organic solutes through phloem from sources to sinks.
Cartão 545
Pergunta
How do a source and a sink differ in plant transport?
Resposta
A source releases assimilates to phloem; a sink removes them for use or storage.
Cartão 546
Pergunta
What makes human circulation a double circulation?
Resposta
Blood passes through the heart once in the pulmonary circuit and again in the systemic circuit during one complete journey.
Cartão 547
Pergunta
Which term describes water-vapor loss from plant surfaces?
Resposta
transpiration
Cartão 548
Pergunta
Which term describes movement of organic solutes through phloem?
Resposta
phloem translocation
Cartão 549
Pergunta
Which term describes the exporting and importing regions of phloem transport?
Resposta
source and sink
Cartão 550
Pergunta
How is an artery adapted to high pressure?
Resposta
It has thick elastic and muscular walls and a relatively narrow lumen.
Cartão 551
Pergunta
How is a vein adapted to return low-pressure blood?
Resposta
It has a wide lumen, thinner walls, and valves that reduce backflow.
Cartão 552
Pergunta
How does capillary structure support exchange?
Resposta
One-cell-thick walls give a short diffusion distance; extensive branching gives a large total area; narrow lumens slow flow and keep blood close to tissues.
Cartão 553
Pergunta
What determines whether a heart valve opens or closes?
Resposta
Pressure differences across the valve.
Cartão 554
Pergunta
Trace water from soil to the atmosphere through a plant.
Resposta
Soil → root hairs → root tissues → xylem → leaf mesophyll → leaf air spaces → stomata → atmosphere.
Cartão 555
Pergunta
Why may root cells use active transport to absorb mineral ions?
Resposta
Ion concentrations can be lower in soil than in root cells, so uptake must occur against a gradient.
Cartão 556
Pergunta
Why do large multicellular organisms need bulk transport systems?
Resposta
Their low surface-area-to-volume ratio and long diffusion distances make diffusion alone too slow for whole-body supply.
Cartão 557
Pergunta
Why does hemoglobin unload more oxygen in actively respiring tissues?
Resposta
Lower oxygen and often higher carbon dioxide and acidity reduce hemoglobin's oxygen affinity.
Cartão 558
Pergunta
How does transpiration pull water upward through xylem?
Resposta
Evaporation lowers leaf water potential and creates tension; cohesion transmits the pull through the continuous water column.
Cartão 559
Pergunta
How do wind and low humidity generally affect transpiration?
Resposta
Both maintain a steep water-vapor gradient outside the leaf, increasing transpiration if stomata remain open.
Cartão 560
Pergunta
What drives mass flow in phloem?
Resposta
Sugar loading draws in water and raises pressure at a source; unloading lowers pressure at a sink, producing bulk flow.
Cartão 561
Pergunta
Can the same plant organ be a source at one time and a sink at another?
Resposta
Yes. A storage organ may import sugars while filling and export them later during growth or germination.
Cartão 562
Pergunta
What is a neuron?
Resposta
An excitable cell specialized to receive, process, and transmit information.
Cartão 563
Pergunta
What is a sensory neuron?
Resposta
A neuron carrying information from a receptor toward the central nervous system.
Cartão 564
Pergunta
What is a motor neuron?
Resposta
A neuron carrying commands from the central nervous system to an effector.
Cartão 565
Pergunta
What is the resting potential?
Resposta
The voltage difference across an unstimulated neuron's membrane, with the inside negative relative to outside.
Cartão 566
Pergunta
Which term describes an excitable information-transmitting cell?
Resposta
a neuron
Cartão 567
Pergunta
Which term describes a neuron carrying receptor information to the CNS?
Resposta
a sensory neuron
Cartão 568
Pergunta
Which term describes a neuron carrying CNS commands to an effector?
Resposta
a motor neuron
Cartão 569
Pergunta
Which term describes the negative-inside voltage of an unstimulated neuron?
Resposta
the resting potential
Cartão 570
Pergunta
What is an action potential?
Resposta
A brief, self-propagating reversal and restoration of membrane potential along an excitable membrane.
Cartão 571
Pergunta
What is depolarization?
Resposta
A change that makes membrane potential less negative, and during an action potential often positive.
Cartão 572
Pergunta
What is repolarization?
Resposta
Return of membrane potential toward its resting negative value after depolarization.
Cartão 573
Pergunta
What is a synapse?
Resposta
A junction where one cell communicates with another cell.
Cartão 574
Pergunta
Which term describes a brief propagating change in neuron membrane voltage?
Resposta
an action potential
Cartão 575
Pergunta
Which term describes a membrane-voltage change toward a less negative value?
Resposta
depolarization
Cartão 576
Pergunta
Which term describes return toward resting membrane voltage?
Resposta
repolarization
Cartão 577
Pergunta
Which term describes a communication junction between cells?
Resposta
a synapse
Cartão 578
Pergunta
What is a neurotransmitter?
Resposta
A chemical released by a neuron that changes the activity of a target cell.
Cartão 579
Pergunta
What is the refractory period?
Resposta
A brief period after an action potential when another is impossible or requires a stronger stimulus.
Cartão 580
Pergunta
What is myelin?
Resposta
An insulating sheath around some axons that speeds impulse conduction.
Cartão 581
Pergunta
What happens when membrane depolarization reaches threshold?
Resposta
Voltage-gated channels trigger the self-amplifying events of an action potential.
Cartão 582
Pergunta
Which term describes a neuron-released signaling chemical?
Resposta
a neurotransmitter
Cartão 583
Pergunta
Which term describes the recovery interval after an action potential?
Resposta
the refractory period
Cartão 584
Pergunta
Which term describes the insulating axon sheath?
Resposta
myelin
Cartão 585
Pergunta
What does the all-or-none principle mean for an action potential?
Resposta
Once threshold is reached, the action potential has a characteristic size; stronger stimuli increase frequency, not its amplitude.
Cartão 586
Pergunta
How does myelin increase conduction speed?
Resposta
Depolarizing current travels rapidly beneath myelin and action potentials regenerate mainly at gaps in the sheath.
Cartão 587
Pergunta
What is the basic sequence at a chemical synapse?
Resposta
An impulse triggers neurotransmitter release; it diffuses across the cleft, binds receptors, and alters the postsynaptic cell.
Cartão 588
Pergunta
Why can a reflex response be rapid?
Resposta
A short neural pathway produces an automatic response without waiting for conscious processing.
Cartão 589
Pergunta
What is sensory transduction?
Resposta
Conversion of a physical or chemical stimulus into an electrical signal in a receptor cell.
Cartão 590
Pergunta
How does an action potential propagate along an axon?
Resposta
Local current depolarizes the next membrane region to threshold, opening voltage-gated channels there.
Cartão 591
Pergunta
Why does an action potential normally travel in one direction along an axon?
Resposta
The membrane just behind it is refractory and cannot immediately fire again.
Cartão 592
Pergunta
How is neurotransmitter action ended?
Resposta
The transmitter is removed by enzymatic breakdown, reuptake, or diffusion away.
Cartão 593
Pergunta
What is sensory adaptation?
Resposta
Reduced receptor or neural response during a constant, unchanging stimulus.
Cartão 594
Pergunta
How can a drug alter synaptic transmission?
Resposta
It may mimic or block a transmitter, change its release, or change its removal from the synaptic cleft.
Cartão 595
Pergunta
What is an organ system?
Resposta
A group of organs coordinating to perform major functions for an organism.
Cartão 596
Pergunta
What is a hormone?
Resposta
A signaling molecule released into transport fluid and acting on target cells with suitable receptors.
Cartão 597
Pergunta
What is an endocrine gland?
Resposta
A gland that secretes hormones into extracellular fluid and blood rather than through a duct.
Cartão 598
Pergunta
What is a hormone target cell?
Resposta
A cell able to respond because it has the appropriate receptor.
Cartão 599
Pergunta
Which term describes a coordinated group of organs?
Resposta
an organ system
Cartão 600
Pergunta
Which term describes a long-distance chemical messenger carried in body fluid?
Resposta
a hormone
Cartão 601
Pergunta
Which term describes a ductless hormone-secreting gland?
Resposta
an endocrine gland
Cartão 602
Pergunta
Which term describes a cell with a receptor for a particular hormone?
Resposta
a hormone target cell
Cartão 603
Pergunta
What is digestion?
Resposta
Mechanical and chemical breakdown of food into molecules small enough to absorb.
Cartão 604
Pergunta
What is absorption?
Resposta
Movement of digested nutrients across an exchange surface into blood or lymph.
Cartão 605
Pergunta
What is peristalsis?
Resposta
Coordinated waves of smooth-muscle contraction that move material through the digestive tract.
Cartão 606
Pergunta
What is an intestinal villus?
Resposta
A finger-like projection increasing the absorptive surface of the small intestine.
Cartão 607
Pergunta
Which term describes breakdown of food into absorbable molecules?
Resposta
digestion
Cartão 608
Pergunta
Which term describes movement of digested nutrients into transport fluids?
Resposta
absorption
Cartão 609
Pergunta
Which term describes wave-like gut contractions moving contents?
Resposta
peristalsis
Cartão 610
Pergunta
Which term describes a finger-like intestinal absorption projection?
Resposta
an intestinal villus
Cartão 611
Pergunta
What is excretion?
Resposta
Removal of metabolic waste products from the body.
Cartão 612
Pergunta
What is a nephron?
Resposta
The microscopic functional unit of the kidney that filters blood and modifies filtrate into urine.
Cartão 613
Pergunta
What is ultrafiltration?
Resposta
Pressure-driven filtration of small molecules from blood into a kidney capsule while cells and most proteins remain in blood.
Cartão 614
Pergunta
What is selective reabsorption?
Resposta
Recovery of useful substances and regulated amounts of water and ions from kidney filtrate into blood.
Cartão 615
Pergunta
Which term describes removal of metabolic wastes?
Resposta
excretion
Cartão 616
Pergunta
Which term describes the kidney's microscopic functional unit?
Resposta
a nephron
Cartão 617
Pergunta
Which term describes pressure filtration at the start of a nephron?
Resposta
ultrafiltration
Cartão 618
Pergunta
Which term describes return of useful substances from kidney filtrate to blood?
Resposta
selective reabsorption
Cartão 619
Pergunta
What is skeletal muscle?
Resposta
Striated voluntary muscle attached to the skeleton and used for movement and posture.
Cartão 620
Pergunta
What is an antagonistic muscle pair?
Resposta
Two muscles producing opposite movements at a joint because muscles pull but do not push.
Cartão 621
Pergunta
How do nervous and endocrine signaling generally differ?
Resposta
Neural signals are rapid and targeted; hormonal signals are usually slower, longer-lasting, and distributed through body fluids.
Cartão 622
Pergunta
Why does a circulating hormone affect only some cells?
Resposta
Only target cells express receptors that recognize the hormone and activate a response.
Cartão 623
Pergunta
Which term describes voluntary striated muscle that moves the skeleton?
Resposta
skeletal muscle
Cartão 624
Pergunta
Which term describes two muscles producing opposite joint movements?
Resposta
an antagonistic muscle pair
Cartão 625
Pergunta
What is the final absorbable product of most dietary carbohydrate digestion?
Resposta
Monosaccharides, especially glucose.
Cartão 626
Pergunta
What are the main absorbable products of protein digestion?
Resposta
Amino acids and small peptides that are completed to amino acids during absorption.
Cartão 627
Pergunta
How is the small intestine adapted for absorption?
Resposta
Folds, villi, and microvilli increase area; a thin epithelium, rich blood supply, and lymph vessels support transport.
Cartão 628
Pergunta
Name three integrative roles of the liver.
Resposta
It processes absorbed nutrients, regulates blood chemistry, detoxifies substances, produces bile, and converts ammonia to urea; any three are sufficient.
Cartão 629
Pergunta
Why are blood cells and most plasma proteins absent from normal kidney filtrate?
Resposta
They are too large to cross the filtration barrier.
Cartão 630
Pergunta
How do muscles move a bone at a joint?
Resposta
Contraction shortens the muscle, pulling through a tendon on the bone.
Cartão 631
Pergunta
Why are antagonistic muscles needed at many joints?
Resposta
A muscle can pull in one direction but cannot push itself back, so an opposing muscle produces the reverse movement.
Cartão 632
Pergunta
Why must organ systems be integrated rather than acting independently?
Resposta
Each system depends on materials, signals, waste removal, and stable conditions supplied by other systems.
Cartão 633
Pergunta
Why do many absorbed lipids enter lymph before blood?
Resposta
Intestinal cells package them into lipoprotein particles too large to enter ordinary blood capillaries directly.
Cartão 634
Pergunta
Why is glucose normally absent from final urine?
Resposta
Filtered glucose is selectively reabsorbed into blood when transporter capacity is not exceeded.
Cartão 635
Pergunta
How do respiratory, circulatory, and muscular systems cooperate during exercise?
Resposta
Ventilation supplies oxygen, circulation transports gases and fuels, and muscles use ATP while returning carbon dioxide, heat, and metabolites.
Cartão 636
Pergunta
How do liver, circulation, and kidneys cooperate in nitrogen-waste removal?
Resposta
The liver converts toxic ammonia to urea, blood carries urea, and kidneys filter and excrete it.
Cartão 637
Pergunta
What is a pathogen?
Resposta
A biological agent capable of causing disease.
Cartão 638
Pergunta
What is an antigen?
Resposta
A molecule recognized specifically by an antibody or lymphocyte receptor.
Cartão 639
Pergunta
What is innate immunity?
Resposta
Rapid, nonspecific defense mechanisms present without prior exposure.
Cartão 640
Pergunta
What is adaptive immunity?
Resposta
Specific defense that develops through lymphocyte activation and can form memory.
Cartão 641
Pergunta
Which term describes a disease-causing biological agent?
Resposta
a pathogen
Cartão 642
Pergunta
Which term describes a molecule specifically recognized by adaptive immune receptors?
Resposta
an antigen
Cartão 643
Pergunta
Which term describes rapid nonspecific immune defense?
Resposta
innate immunity
Cartão 644
Pergunta
Which term describes specific immune defense capable of memory?
Resposta
adaptive immunity
Cartão 645
Pergunta
What is a phagocyte?
Resposta
A cell that engulfs and digests microbes, particles, or damaged cells.
Cartão 646
Pergunta
What is a lymphocyte?
Resposta
An adaptive immune cell with receptors specific to particular antigens.
Cartão 647
Pergunta
What is an antibody?
Resposta
A secreted immunoglobulin that binds a specific antigen.
Cartão 648
Pergunta
What is a B lymphocyte?
Resposta
A lymphocyte that can differentiate into antibody-secreting plasma cells and memory cells.
Cartão 649
Pergunta
Which term describes an engulfing immune cell?
Resposta
a phagocyte
Cartão 650
Pergunta
Which term describes an antigen-specific adaptive immune cell?
Resposta
a lymphocyte
Cartão 651
Pergunta
Which term describes a secreted antigen-binding immunoglobulin?
Resposta
an antibody
Cartão 652
Pergunta
Which term describes the lymphocyte lineage that produces antibody-secreting cells?
Resposta
a B lymphocyte
Cartão 653
Pergunta
What is a helper T cell?
Resposta
A lymphocyte that coordinates immune responses through contact signals and cytokines.
Cartão 654
Pergunta
What is an immune memory cell?
Resposta
A long-lived lymphocyte that responds rapidly after re-exposure to its antigen.
Cartão 655
Pergunta
What is vaccination?
Resposta
Deliberate exposure to a safe form or component of an antigen to generate protective immune memory.
Cartão 656
Pergunta
What is an antibiotic?
Resposta
A substance that kills bacteria or inhibits their growth at clinically useful doses.
Cartão 657
Pergunta
Which term describes the T cell that coordinates other immune cells?
Resposta
a helper T cell
Cartão 658
Pergunta
Which term describes a long-lived lymphocyte enabling faster re-exposure response?
Resposta
an immune memory cell
Cartão 659
Pergunta
Which term describes safe antigen exposure used to create immune memory?
Resposta
vaccination
Cartão 660
Pergunta
Which term describes a drug acting against bacteria?
Resposta
an antibiotic
Cartão 661
Pergunta
What are examples of first-line defenses against pathogens?
Resposta
Intact skin, mucus, cilia, antimicrobial secretions, stomach acidity, and competing microbiota.
Cartão 662
Pergunta
How does inflammation help defend damaged tissue?
Resposta
It increases local blood flow and vessel permeability and recruits immune cells and defensive molecules.
Cartão 663
Pergunta
What happens during phagocytosis?
Resposta
A cell surrounds a particle in a vesicle, then fuses it with digestive compartments to destroy or process it.
Cartão 664
Pergunta
How can antibodies help eliminate a pathogen?
Resposta
They can neutralize targets, block attachment, clump particles, and mark them for phagocytosis or complement attack.
Cartão 665
Pergunta
Why can a vaccine generate protection without causing the full disease?
Resposta
It presents antigen in a weakened, inactivated, partial, or encoded form that stimulates immunity with much lower risk.
Cartão 666
Pergunta
Why do antibiotics not treat viral infections?
Resposta
Viruses lack the bacterial structures and independent metabolic processes targeted by antibiotics.
Cartão 667
Pergunta
What determines the antigen specificity of a lymphocyte?
Resposta
The molecular shape and chemistry of its unique surface receptor.
Cartão 668
Pergunta
What is clonal selection?
Resposta
An antigen activates lymphocytes with matching receptors, causing them to proliferate and differentiate.
Cartão 669
Pergunta
Why is a secondary adaptive immune response usually faster and stronger?
Resposta
Memory cells are more numerous and activate rapidly, producing effective cells and antibodies sooner.
Cartão 670
Pergunta
How can high vaccination coverage protect some unvaccinated people?
Resposta
Reduced transmission makes encounters with infectious individuals less likely, though protection is incomplete and pathogen-dependent.
Cartão 671
Pergunta
How does antibiotic use select for resistant bacteria?
Resposta
Susceptible bacteria are removed while resistant variants survive and reproduce, increasing resistance-allele frequency.
Cartão 672
Pergunta
Why can unnecessary or incomplete antibiotic exposure promote resistance?
Resposta
It creates selection favoring resistant cells while potentially leaving surviving bacteria to multiply and spread.
Cartão 673
Pergunta
What is an allergy?
Resposta
An immune response to a normally harmless antigen that causes tissue symptoms or damage.
Cartão 674
Pergunta
What is asexual reproduction?
Resposta
Production of offspring from one parent without fusion of gametes.
Cartão 675
Pergunta
What is sexual reproduction?
Resposta
Production of offspring involving fusion of haploid gametes.
Cartão 676
Pergunta
What is a gamete?
Resposta
A haploid reproductive cell able to fuse with another gamete.
Cartão 677
Pergunta
What is fertilization?
Resposta
Fusion of gamete nuclei to form a diploid zygote.
Cartão 678
Pergunta
Which term describes reproduction without gamete fusion?
Resposta
asexual reproduction
Cartão 679
Pergunta
Which term describes reproduction involving gamete fusion?
Resposta
sexual reproduction
Cartão 680
Pergunta
Which term describes a haploid reproductive cell?
Resposta
a gamete
Cartão 681
Pergunta
Which term describes fusion of gamete nuclei?
Resposta
fertilization
Cartão 682
Pergunta
What is a zygote?
Resposta
The diploid cell formed by fertilization.
Cartão 683
Pergunta
What is meiosis?
Resposta
Cell division that halves chromosome number and usually produces genetically varied haploid cells.
Cartão 684
Pergunta
What is ovulation?
Resposta
Release of a secondary oocyte from an ovary.
Cartão 685
Pergunta
What is implantation?
Resposta
Attachment and embedding of an early embryo in the uterine lining.
Cartão 686
Pergunta
Which term describes the first diploid cell after fertilization?
Resposta
a zygote
Cartão 687
Pergunta
Which term describes division producing varied haploid cells?
Resposta
meiosis
Cartão 688
Pergunta
Which term describes release of an oocyte from an ovary?
Resposta
ovulation
Cartão 689
Pergunta
Which term describes embedding of an early embryo in the uterine lining?
Resposta
implantation
Cartão 690
Pergunta
What is the placenta?
Resposta
A temporary organ that exchanges materials between maternal and fetal blood supplies without normally mixing them directly.
Cartão 691
Pergunta
What is pollination?
Resposta
Transfer of pollen from an anther to a receptive stigma.
Cartão 692
Pergunta
Why does sexual reproduction usually produce more genetic variation than asexual reproduction?
Resposta
Meiosis reshuffles alleles and random fertilization combines genomes from two gametes.
Cartão 693
Pergunta
Why must gametes be haploid?
Resposta
Fusion of two haploid gametes restores the diploid chromosome number instead of doubling it each generation.
Cartão 694
Pergunta
Which term describes the maternal-fetal exchange organ?
Resposta
the placenta
Cartão 695
Pergunta
Which term describes transfer of pollen to a stigma?
Resposta
pollination
Cartão 696
Pergunta
What are major roles of FSH in the ovarian cycle?
Resposta
It stimulates follicle development and supports estrogen secretion.
Cartão 697
Pergunta
What is a major role of the mid-cycle LH surge?
Resposta
It triggers ovulation and formation of the corpus luteum.
Cartão 698
Pergunta
How does estrogen contribute to the uterine cycle?
Resposta
It promotes repair and thickening of the uterine lining after menstruation.
Cartão 699
Pergunta
How does progesterone contribute to the uterine cycle?
Resposta
It maintains a thick, secretory uterine lining after ovulation.
Cartão 700
Pergunta
Where does human fertilization usually occur?
Resposta
In an oviduct, before the early embryo reaches the uterus.
Cartão 701
Pergunta
What happens after compatible pollen reaches a flower's stigma?
Resposta
A pollen tube grows toward an ovule and delivers male nuclei for fertilization.
Cartão 702
Pergunta
Why does menstruation usually begin if pregnancy does not occur?
Resposta
The corpus luteum degenerates, progesterone and estrogen fall, and the uterine lining is no longer maintained.
Cartão 703
Pergunta
What substances commonly cross the placenta between mother and fetus?
Resposta
Oxygen and nutrients move toward the fetus; carbon dioxide and nitrogenous wastes move toward the mother.
Cartão 704
Pergunta
How can contraception prevent pregnancy in different ways?
Resposta
Methods can inhibit ovulation, block sperm from reaching an egg, prevent fertilization, or permanently interrupt the reproductive ducts.
Cartão 705
Pergunta
What is homeostasis?
Resposta
Maintenance of internal conditions within ranges compatible with normal function despite change.
Cartão 706
Pergunta
What is negative feedback?
Resposta
Control in which a deviation triggers responses that oppose the original change.
Cartão 707
Pergunta
What is a set point?
Resposta
The target value or range around which a regulated variable is maintained.
Cartão 708
Pergunta
What is a homeostatic receptor?
Resposta
A sensor that detects a change in a regulated variable.
Cartão 709
Pergunta
Which term describes maintenance of a stable functional internal environment?
Resposta
homeostasis
Cartão 710
Pergunta
Which term describes feedback that counteracts a deviation?
Resposta
negative feedback
Cartão 711
Pergunta
Which term describes the target around which a variable is regulated?
Resposta
a set point
Cartão 712
Pergunta
Which term describes the sensor in a feedback system?
Resposta
a homeostatic receptor
Cartão 713
Pergunta
What is a control center?
Resposta
The component that compares information with a target and coordinates a response.
Cartão 714
Pergunta
What is an effector?
Resposta
A muscle, gland, or other component that carries out a control response.
Cartão 715
Pergunta
What is thermoregulation?
Resposta
Control of body temperature within a functional range.
Cartão 716
Pergunta
What is vasodilation?
Resposta
Widening of blood vessels, often increasing blood flow near the skin.
Cartão 717
Pergunta
Which term describes the feedback component that evaluates input and directs a response?
Resposta
a control center
Cartão 718
Pergunta
Which term describes the component that executes a physiological response?
Resposta
an effector
Cartão 719
Pergunta
Which term describes physiological regulation of body temperature?
Resposta
thermoregulation
Cartão 720
Pergunta
Which term describes widening of blood vessels?
Resposta
vasodilation
Cartão 721
Pergunta
What is vasoconstriction?
Resposta
Narrowing of blood vessels, often reducing blood flow near the skin.
Cartão 722
Pergunta
What is insulin?
Resposta
A pancreatic hormone that lowers elevated blood glucose by promoting uptake and storage.
Cartão 723
Pergunta
What is glucagon?
Resposta
A pancreatic hormone that raises low blood glucose by promoting release of stored fuel.
Cartão 724
Pergunta
What are the main components of a homeostatic feedback loop?
Resposta
A regulated variable, receptor, control center, effectors, and responses that alter the variable.
Cartão 725
Pergunta
Which term describes narrowing of blood vessels?
Resposta
vasoconstriction
Cartão 726
Pergunta
Which term describes the pancreatic hormone that lowers blood glucose?
Resposta
insulin
Cartão 727
Pergunta
Which term describes the pancreatic hormone that raises blood glucose?
Resposta
glucagon
Cartão 728
Pergunta
What happens when blood glucose rises after a meal?
Resposta
Insulin secretion increases, promoting glucose uptake and storage so blood glucose falls toward its normal range.
Cartão 729
Pergunta
What happens when blood glucose falls during fasting?
Resposta
Glucagon secretion increases, promoting glycogen breakdown and glucose release by the liver.
Cartão 730
Pergunta
How does sweating cool the body?
Resposta
Evaporation of water from skin transfers heat to the environment.
Cartão 731
Pergunta
How does skin vasodilation increase heat loss?
Resposta
It brings more warm blood near the surface, increasing transfer of heat to the environment.
Cartão 732
Pergunta
How does shivering warm the body?
Resposta
Rapid involuntary muscle contractions increase respiration and heat production.
Cartão 733
Pergunta
Does homeostasis keep internal conditions perfectly constant?
Resposta
No. Variables fluctuate within controlled ranges around target values.
Cartão 734
Pergunta
How does ADH help conserve water?
Resposta
It increases water permeability in kidney collecting ducts, so more water is reabsorbed and urine becomes more concentrated.
Cartão 735
Pergunta
How should ADH secretion change during dehydration?
Resposta
It should increase, promoting greater water reabsorption by the kidneys.
Cartão 736
Pergunta
How does positive feedback differ from negative feedback?
Resposta
Positive feedback amplifies a change until an endpoint; negative feedback opposes a change and stabilizes a variable.
Cartão 737
Pergunta
Why can diabetes mellitus cause persistently high blood glucose?
Resposta
Insulin production may be insufficient or target cells may respond poorly to insulin.
Cartão 738
Pergunta
What is biological evolution?
Resposta
Change in heritable characteristics or allele frequencies of a population across generations.
Cartão 739
Pergunta
What is allele frequency?
Resposta
The proportion of gene copies in a population represented by a particular allele.
Cartão 740
Pergunta
What is microevolution?
Resposta
Evolutionary change in allele frequencies within populations over relatively short timescales.
Cartão 741
Pergunta
What is speciation?
Resposta
Evolutionary formation of new species.
Cartão 742
Pergunta
Which term describes change in a population's heritable composition across generations?
Resposta
biological evolution
Cartão 743
Pergunta
Which term describes the proportion of a population's gene copies that are one allele?
Resposta
allele frequency
Cartão 744
Pergunta
Which term describes short-timescale allele-frequency change within populations?
Resposta
microevolution
Cartão 745
Pergunta
Which term describes formation of new species?
Resposta
speciation
Cartão 746
Pergunta
What is reproductive isolation?
Resposta
Barriers that prevent or greatly reduce gene flow between populations.
Cartão 747
Pergunta
What is allopatric speciation?
Resposta
Speciation after populations become geographically separated and diverge.
Cartão 748
Pergunta
What is sympatric speciation?
Resposta
Speciation without geographic separation, through reproductive isolation within the same area.
Cartão 749
Pergunta
What are homologous structures?
Resposta
Structures similar because they were inherited from a common ancestor, even if their functions differ.
Cartão 750
Pergunta
Which term describes barriers reducing gene flow between populations?
Resposta
reproductive isolation
Cartão 751
Pergunta
Which term describes speciation following geographic separation?
Resposta
allopatric speciation
Cartão 752
Pergunta
Which term describes speciation within the same geographic area?
Resposta
sympatric speciation
Cartão 753
Pergunta
Which term describes structures similar through common ancestry?
Resposta
homologous structures
Cartão 754
Pergunta
What are analogous structures?
Resposta
Structures with similar functions that evolved independently rather than from the same ancestral structure.
Cartão 755
Pergunta
What is a common ancestor?
Resposta
An ancestral population from which two or more descendant lineages evolved.
Cartão 756
Pergunta
How does the fossil record provide evidence for evolution?
Resposta
It documents organisms from different times, including appearance, change, persistence, and extinction of lineages.
Cartão 757
Pergunta
How do DNA and protein sequences provide evidence of common ancestry?
Resposta
Shared sequences are inherited; greater similarity generally indicates more recent common ancestry.
Cartão 758
Pergunta
Which term describes functionally similar structures of independent evolutionary origin?
Resposta
analogous structures
Cartão 759
Pergunta
Which term describes an ancestral population shared by descendant lineages?
Resposta
a common ancestor
Cartão 760
Pergunta
What is the evolutionary significance of extinction?
Resposta
It permanently ends a lineage and can alter ecological opportunities and the future diversification of survivors.
Cartão 761
Pergunta
Do individual organisms evolve during their lifetimes?
Resposta
No. Individuals develop and acclimate; evolution is heritable change in populations across generations.
Cartão 762
Pergunta
Why is evolution represented as a branching tree rather than a ladder?
Resposta
Lineages split from common ancestors; living species are not arranged as stages toward a single goal.
Cartão 763
Pergunta
How can island species support evolutionary explanations?
Resposta
Their similarities to nearby mainland ancestors and unique local adaptations fit divergence after colonization and isolation.
Cartão 764
Pergunta
How can geographic isolation lead to reproductive isolation?
Resposta
Separated populations accumulate different mutations and experience different selection and drift until interbreeding is reduced.
Cartão 765
Pergunta
Why can continuing gene flow slow speciation?
Resposta
Movement of alleles between populations counteracts genetic divergence.
Cartão 766
Pergunta
Why can unrelated species evolve similar traits?
Resposta
Similar environmental challenges can favor similar functional solutions through convergent evolution.
Cartão 767
Pergunta
Which parts of evolution are random and which are nonrandom?
Resposta
Mutation and many sampling effects are random with respect to need; natural selection nonrandomly favors variants that reproduce better in a given environment.
Cartão 768
Pergunta
What is conservation biology?
Resposta
The science and practice of protecting biodiversity, ecological processes, and evolutionary potential.
Cartão 769
Pergunta
What is habitat fragmentation?
Resposta
Division of continuous habitat into smaller, isolated patches.
Cartão 770
Pergunta
What is an endangered species?
Resposta
A species facing a high risk of extinction in the wild.
Cartão 771
Pergunta
What is in situ conservation?
Resposta
Protection of species in their natural habitats and ecological communities.
Cartão 772
Pergunta
Which term describes the protection of biodiversity and ecological processes?
Resposta
conservation biology
Cartão 773
Pergunta
Which term describes division of habitat into isolated patches?
Resposta
habitat fragmentation
Cartão 774
Pergunta
Which term describes a species at high risk of extinction?
Resposta
an endangered species
Cartão 775
Pergunta
Which term describes conservation within natural habitat?
Resposta
in situ conservation
Cartão 776
Pergunta
What is ex situ conservation?
Resposta
Protection of organisms or genetic material outside the natural habitat.
Cartão 777
Pergunta
What is a population bottleneck?
Resposta
A sharp population reduction that can remove genetic variation by chance.
Cartão 778
Pergunta
What is a wildlife corridor?
Resposta
Habitat connecting isolated patches to permit movement and gene flow.
Cartão 779
Pergunta
What major human-driven processes threaten biodiversity?
Resposta
Habitat loss, overexploitation, invasive species, pollution, and climate change.
Cartão 780
Pergunta
Which term describes conservation outside natural habitat?
Resposta
ex situ conservation
Cartão 781
Pergunta
Which term describes a severe population reduction that loses genetic diversity?
Resposta
a population bottleneck
Cartão 782
Pergunta
Which term describes habitat linking isolated populations?
Resposta
a wildlife corridor
Cartão 783
Pergunta
What makes a protected area more effective than a boundary alone?
Resposta
Adequate size, representative habitat, enforcement, connectivity, local support, and management of external threats.
Cartão 784
Pergunta
Why is long-term population monitoring important in conservation?
Resposta
It reveals trends, tests whether management works, and provides early warning of decline.
Cartão 785
Pergunta
How can ecosystem services support the case for conservation?
Resposta
Healthy ecosystems provide benefits such as pollination, water purification, carbon storage, soil formation, and cultural value.
Cartão 786
Pergunta
Why are very small populations especially vulnerable to extinction?
Resposta
Chance events, inbreeding, low genetic diversity, and difficulty finding mates can reinforce decline.
Cartão 787
Pergunta
What are benefits and limits of captive-breeding programs?
Resposta
They can prevent immediate extinction and manage breeding, but may lose diversity, alter behavior, and fail without safe habitat for release.
Cartão 788
Pergunta
Why can controlling an invasive species aid conservation?
Resposta
It can reduce predation, competition, disease, or habitat alteration affecting native species.
Cartão 789
Pergunta
Why must conservation priorities consider more than species count?
Resposta
Endemism, evolutionary distinctness, ecological roles, threat severity, feasibility, and human needs also matter.
Cartão 790
Pergunta
What is an adaptation?
Resposta
A heritable characteristic that increases reproductive success in a particular environment.
Cartão 791
Pergunta
What is acclimation?
Resposta
A reversible physiological or behavioral adjustment by an individual to environmental change.
Cartão 792
Pergunta
What is a structural adaptation?
Resposta
An inherited anatomical feature that improves performance in an environment.
Cartão 793
Pergunta
What is a physiological adaptation?
Resposta
An inherited functional or biochemical feature that improves performance in an environment.
Cartão 794
Pergunta
Which term describes a heritable trait improving reproductive success in context?
Resposta
an adaptation
Cartão 795
Pergunta
Which term describes an individual's reversible adjustment to environmental change?
Resposta
acclimation
Cartão 796
Pergunta
Which term describes an adaptive anatomical feature?
Resposta
a structural adaptation
Cartão 797
Pergunta
Which term describes an adaptive functional or biochemical feature?
Resposta
a physiological adaptation
Cartão 798
Pergunta
What is a behavioral adaptation?
Resposta
An inherited behavior pattern that improves survival or reproduction.
Cartão 799
Pergunta
What is an environmental tolerance range?
Resposta
The range of an abiotic condition within which an organism can survive and reproduce.
Cartão 800
Pergunta
What is evolutionary fitness?
Resposta
Relative contribution of an individual or genotype to future generations.
Cartão 801
Pergunta
How can a thick cuticle and reduced leaves help a desert plant?
Resposta
The cuticle lowers surface permeability, while smaller leaves reduce the area from which water can evaporate.
Cartão 802
Pergunta
Which term describes an adaptive behavior pattern?
Resposta
a behavioral adaptation
Cartão 803
Pergunta
Which term describes the survivable range of an abiotic condition?
Resposta
an environmental tolerance range
Cartão 804
Pergunta
Which term describes relative reproductive contribution to future generations?
Resposta
evolutionary fitness
Cartão 805
Pergunta
How can a streamlined body adapt an aquatic animal to movement?
Resposta
It reduces drag, lowering the energy needed to move through water.
Cartão 806
Pergunta
Does an organism develop an adaptation because it needs one?
Resposta
No. Heritable variants arise without regard to need, and selection changes their frequencies across generations.
Cartão 807
Pergunta
Why may organisms from different thermal environments have enzymes with different temperature optima?
Resposta
Selection favors protein structures that balance flexibility and stability under local temperatures.
Cartão 808
Pergunta
Why is an adaptation rarely beneficial in every environment?
Resposta
Traits carry costs and their advantage depends on local resources, competitors, predators, and physical conditions.
Cartão 809
Pergunta
How does phenotypic plasticity differ from genetic adaptation?
Resposta
Plasticity lets one genotype produce different phenotypes; adaptation is a heritable population trait shaped across generations.
Cartão 810
Pergunta
What is local adaptation?
Resposta
A population has higher fitness in its home environment than foreign populations because selection favored local traits.
Cartão 811
Pergunta
What is an ecological niche?
Resposta
The set of environmental conditions, resources, interactions, and functional roles associated with a species.
Cartão 812
Pergunta
What is a habitat?
Resposta
The physical place or environment where an organism lives.
Cartão 813
Pergunta
What is a fundamental niche?
Resposta
The full range of conditions and resources a species could use without limiting biotic interactions.
Cartão 814
Pergunta
What is a realized niche?
Resposta
The conditions and resources a species actually uses after competition and other interactions.
Cartão 815
Pergunta
Which term describes a species' environmental requirements and ecological role?
Resposta
an ecological niche
Cartão 816
Pergunta
Which term describes the place where an organism lives?
Resposta
a habitat
Cartão 817
Pergunta
Which term describes the potential niche without limiting biotic interactions?
Resposta
a fundamental niche
Cartão 818
Pergunta
Which term describes the niche actually occupied in nature?
Resposta
a realized niche
Cartão 819
Pergunta
What is competition?
Resposta
An interaction in which organisms reduce one another's access to a limited resource.
Cartão 820
Pergunta
What is mutualism?
Resposta
An interaction in which both participating species benefit.
Cartão 821
Pergunta
What is predation?
Resposta
An interaction in which one organism kills and consumes another.
Cartão 822
Pergunta
How does a habitat differ from a niche?
Resposta
A habitat is where an organism lives; a niche includes how it uses conditions and resources and interacts there.
Cartão 823
Pergunta
Which term describes an interaction over a limited resource that harms both competitors?
Resposta
competition
Cartão 824
Pergunta
Which term describes an interspecific interaction benefiting both partners?
Resposta
mutualism
Cartão 825
Pergunta
Which term describes an interaction where one organism kills and eats another?
Resposta
predation
Cartão 826
Pergunta
What kinds of factors define a niche?
Resposta
Abiotic factors such as temperature and moisture, plus biotic factors such as food, competitors, predators, and partners.
Cartão 827
Pergunta
What does competitive exclusion predict?
Resposta
Species with effectively identical niches cannot coexist indefinitely under stable conditions; one is excluded or niches diverge.
Cartão 828
Pergunta
How can resource partitioning reduce competition?
Resposta
Species use different resources, places, or times, reducing niche overlap.
Cartão 829
Pergunta
What is a keystone species?
Resposta
A species whose effect on community structure is disproportionately large relative to its abundance.
Cartão 830
Pergunta
Why can an introduced species expand rapidly in a new community?
Resposta
It may encounter abundant resources, suitable climate, and fewer predators, pathogens, or competitors.
Cartão 831
Pergunta
Can an organism alter the niche conditions of other species?
Resposta
Yes. Ecosystem engineers modify habitat structure or resource availability, changing opportunities for other organisms.
Cartão 832
Pergunta
What is a population?
Resposta
Individuals of the same species living in the same area at the same time.
Cartão 833
Pergunta
What is an ecological community?
Resposta
Populations of different species living and interacting in an area.
Cartão 834
Pergunta
What is an ecosystem?
Resposta
A community together with its physical environment and their interactions.
Cartão 835
Pergunta
What is carrying capacity?
Resposta
The population size an environment can sustain over time under given conditions.
Cartão 836
Pergunta
Which term describes same-species individuals sharing an area and time?
Resposta
a population
Cartão 837
Pergunta
Which term describes interacting populations of different species?
Resposta
an ecological community
Cartão 838
Pergunta
Which term describes a community plus its abiotic environment?
Resposta
an ecosystem
Cartão 839
Pergunta
Which term describes the long-term supportable population size?
Resposta
carrying capacity
Cartão 840
Pergunta
What is population density?
Resposta
The number of individuals per unit area or volume.
Cartão 841
Pergunta
What is a limiting factor?
Resposta
A resource or condition that restricts population growth or distribution.
Cartão 842
Pergunta
What is a density-dependent factor?
Resposta
A factor whose effect strengthens as population density increases.
Cartão 843
Pergunta
What is a density-independent factor?
Resposta
A factor whose effect is not primarily determined by population density.
Cartão 844
Pergunta
Which term describes individuals per unit area or volume?
Resposta
population density
Cartão 845
Pergunta
Which term describes a resource or condition restricting a population?
Resposta
a limiting factor
Cartão 846
Pergunta
Which term describes a factor with stronger effects at higher density?
Resposta
a density-dependent factor
Cartão 847
Pergunta
Which term describes a factor acting largely regardless of population density?
Resposta
a density-independent factor
Cartão 848
Pergunta
What is exponential population growth?
Resposta
Growth at a constant per-capita rate, producing a J-shaped curve under ideal conditions.
Cartão 849
Pergunta
What is logistic population growth?
Resposta
Growth that slows as population size approaches carrying capacity, producing an S-shaped model.
Cartão 850
Pergunta
What four processes directly change population size?
Resposta
Births and immigration increase it; deaths and emigration decrease it.
Cartão 851
Pergunta
Under what conditions can exponential growth occur temporarily?
Resposta
Resources are abundant and limiting effects such as competition, disease, and predation are weak.
Cartão 852
Pergunta
Which term describes J-shaped growth at constant per-capita rate?
Resposta
exponential population growth
Cartão 853
Pergunta
Which term describes S-shaped growth that slows near carrying capacity?
Resposta
logistic population growth
Cartão 854
Pergunta
Why is infectious disease often density dependent?
Resposta
Close or frequent contact at high density increases transmission opportunities.
Cartão 855
Pergunta
Give an example of a density-independent population factor.
Resposta
A severe storm, wildfire, drought, or freeze can affect populations regardless of their initial density.
Cartão 856
Pergunta
When is quadrat sampling useful?
Resposta
For estimating abundance or frequency of sessile or slow-moving organisms in defined areas.
Cartão 857
Pergunta
What can a transect reveal?
Resposta
How species occurrence or abundance changes along an environmental gradient.
Cartão 858
Pergunta
What can happen when a population overshoots carrying capacity?
Resposta
Resource depletion may raise mortality or lower reproduction, causing decline or oscillation.
Cartão 859
Pergunta
What is the basic mark–recapture estimate of population size?
Resposta
First sample marked × second sample total ÷ marked individuals recaptured.
Cartão 860
Pergunta
What assumptions improve a mark–recapture estimate?
Resposta
Marks persist and do not affect survival, marked individuals mix, capture probability is similar, and the population is effectively closed.
Cartão 861
Pergunta
Why does a correlation between two population variables not prove causation?
Resposta
A third factor, reverse influence, chance, or biased sampling could produce the association.
Cartão 862
Pergunta
What is a trophic level?
Resposta
A feeding position in a food chain or web.
Cartão 863
Pergunta
What is a producer?
Resposta
An autotroph that converts inorganic carbon into organic matter.
Cartão 864
Pergunta
What is a consumer?
Resposta
An organism obtaining energy and matter by eating other organisms or organic material.
Cartão 865
Pergunta
What is a decomposer?
Resposta
An organism that externally digests dead material and wastes and absorbs the products.
Cartão 866
Pergunta
Which term describes a feeding position in an ecosystem?
Resposta
a trophic level
Cartão 867
Pergunta
Which term describes an autotroph forming organic matter?
Resposta
a producer
Cartão 868
Pergunta
Which term describes an organism feeding on other organic matter?
Resposta
a consumer
Cartão 869
Pergunta
Which term describes an organism digesting dead organic matter externally?
Resposta
a decomposer
Cartão 870
Pergunta
What is a food chain?
Resposta
A linear representation of feeding and energy-transfer relationships.
Cartão 871
Pergunta
What is a food web?
Resposta
A network of interconnected feeding relationships in a community.
Cartão 872
Pergunta
What is gross primary productivity?
Resposta
The total rate at which producers capture energy into organic matter.
Cartão 873
Pergunta
What is net primary productivity?
Resposta
Producer energy stored as new biomass after subtracting producer respiration from gross primary productivity.
Cartão 874
Pergunta
Which term describes a linear feeding sequence?
Resposta
a food chain
Cartão 875
Pergunta
Which term describes a network of connected food chains?
Resposta
a food web
Cartão 876
Pergunta
Which term describes the total producer energy-capture rate?
Resposta
gross primary productivity
Cartão 877
Pergunta
Which term describes producer biomass gain after respiration?
Resposta
net primary productivity
Cartão 878
Pergunta
What is ecological productivity?
Resposta
The rate of biomass or energy production per unit area or volume.
Cartão 879
Pergunta
What is a biogeochemical cycle?
Resposta
Movement of an element or compound through organisms and the physical environment.
Cartão 880
Pergunta
Why is less energy available at each higher trophic level?
Resposta
Not all biomass is eaten or digested, and organisms use energy in respiration, movement, maintenance, and heat loss.
Cartão 881
Pergunta
Why does energy flow rather than cycle through an ecosystem?
Resposta
Energy enters mainly as light and ultimately disperses as heat, which ecosystems cannot fully recycle.
Cartão 882
Pergunta
Which term describes the rate of biomass or energy production?
Resposta
ecological productivity
Cartão 883
Pergunta
Which term describes cycling of matter through living and nonliving reservoirs?
Resposta
a biogeochemical cycle
Cartão 884
Pergunta
Why can matter cycle through an ecosystem?
Resposta
Atoms are conserved and repeatedly transferred among organisms, detritus, soil, water, and atmosphere.
Cartão 885
Pergunta
Why is a pyramid of energy always upright?
Resposta
Usable energy decreases between trophic levels because every transfer includes losses.
Cartão 886
Pergunta
How are gross and net primary productivity related?
Resposta
NPP = GPP − producer respiration.
Cartão 887
Pergunta
How do decomposers support nutrient cycling?
Resposta
They break down dead material and wastes, releasing inorganic nutrients for reuse.
Cartão 888
Pergunta
What processes move carbon rapidly between organisms and the atmosphere?
Resposta
Photosynthesis removes carbon dioxide; respiration, decomposition, and combustion release it.
Cartão 889
Pergunta
Why is nitrogen fixation important?
Resposta
It converts atmospheric nitrogen gas into forms that can enter biological nitrogen metabolism.
Cartão 890
Pergunta
How can excess nitrogen or phosphorus cause eutrophication?
Resposta
Nutrient enrichment drives algal growth; decomposition of the biomass consumes oxygen and can create hypoxic water.
Cartão 891
Pergunta
Why can a persistent pollutant reach higher concentrations at higher trophic levels?
Resposta
Predators consume contaminant stored in many prey, and the substance is not readily broken down or excreted.
Cartão 892
Pergunta
How is trophic-transfer efficiency calculated?
Resposta
Energy or biomass gained by the higher trophic level ÷ energy or biomass available at the lower level × 100%.
Cartão 893
Pergunta
What is phenotypic variation?
Resposta
Differences in observable traits among individuals of a population.
Cartão 894
Pergunta
What is heritable variation?
Resposta
Trait differences that can be transmitted genetically to offspring.
Cartão 895
Pergunta
What is a selection pressure?
Resposta
An environmental factor causing differences in survival or reproduction among phenotypes.
Cartão 896
Pergunta
What is relative fitness?
Resposta
An individual's reproductive success compared with others in the population.
Cartão 897
Pergunta
Which term describes observable differences among individuals?
Resposta
phenotypic variation
Cartão 898
Pergunta
Which term describes genetically transmissible trait differences?
Resposta
heritable variation
Cartão 899
Pergunta
Which term describes an environmental factor producing differential reproductive success?
Resposta
a selection pressure
Cartão 900
Pergunta
Which term describes reproductive success relative to other individuals?
Resposta
relative fitness
Cartão 901
Pergunta
What is directional selection?
Resposta
Selection favoring one extreme phenotype and shifting a population's trait distribution.
Cartão 902
Pergunta
What is stabilizing selection?
Resposta
Selection favoring intermediate phenotypes and acting against extremes.
Cartão 903
Pergunta
What is disruptive selection?
Resposta
Selection favoring both extreme phenotypes over intermediates.
Cartão 904
Pergunta
What is sexual selection?
Resposta
Selection arising from differences in mating success.
Cartão 905
Pergunta
Which term describes selection shifting a trait toward one extreme?
Resposta
directional selection
Cartão 906
Pergunta
Which term describes selection favoring intermediate phenotypes?
Resposta
stabilizing selection
Cartão 907
Pergunta
Which term describes selection favoring both trait extremes?
Resposta
disruptive selection
Cartão 908
Pergunta
Which term describes selection caused by unequal mating success?
Resposta
sexual selection
Cartão 909
Pergunta
What conditions are required for natural selection?
Resposta
Individuals vary, some variation is heritable, more offspring are produced than can reproduce, and variants differ in reproductive success.
Cartão 910
Pergunta
How does natural selection produce antibiotic-resistant bacterial populations?
Resposta
Existing resistant variants survive treatment and reproduce more than susceptible bacteria.
Cartão 911
Pergunta
Does an antibiotic cause bacteria to mutate specifically toward resistance?
Resposta
No. Resistance variants arise without regard to need; treatment selects among them.
Cartão 912
Pergunta
Can an individual become genetically adapted through natural selection?
Resposta
No. Selection acts on individuals, but adaptation is a population change across generations.
Cartão 913
Pergunta
How does artificial selection differ from natural selection?
Resposta
Humans choose breeding traits in artificial selection; environmental conditions determine differential reproduction in natural selection.
Cartão 914
Pergunta
How does natural selection change a population?
Resposta
Individuals with advantageous heritable variants leave more offspring, increasing those alleles over generations.
Cartão 915
Pergunta
Why is fitness environment-dependent?
Resposta
A trait that improves reproduction in one environment may be neutral or costly in another.
Cartão 916
Pergunta
How does genetic drift differ from natural selection?
Resposta
Drift changes allele frequencies by chance sampling; selection changes them through consistent fitness differences.
Cartão 917
Pergunta
What is ecosystem stability?
Resposta
The capacity of an ecosystem to maintain or recover its structure and functions despite disturbance.
Cartão 918
Pergunta
What is an ecological tipping point?
Resposta
A threshold beyond which feedbacks can drive a large and difficult-to-reverse ecosystem shift.
Cartão 919
Pergunta
What is a mesocosm?
Resposta
A controlled, simplified ecosystem used to investigate ecological processes under more realistic conditions than a small laboratory vessel.
Cartão 920
Pergunta
What is a sustainable yield?
Resposta
A harvest rate that can continue without causing long-term resource decline under prevailing conditions.
Cartão 921
Pergunta
Which term describes the capacity of an ecosystem to persist or recover after disturbance?
Resposta
ecosystem stability
Cartão 922
Pergunta
Which term describes a threshold triggering a major hard-to-reverse ecosystem shift?
Resposta
an ecological tipping point
Cartão 923
Pergunta
Which term describes a controlled model ecosystem used for experiments?
Resposta
a mesocosm
Cartão 924
Pergunta
Which term describes a harvest rate that avoids long-term depletion?
Resposta
a sustainable yield
Cartão 925
Pergunta
What is eutrophication?
Resposta
Nutrient enrichment of water that stimulates excess primary production and can lead to oxygen depletion.
Cartão 926
Pergunta
What is biomagnification?
Resposta
Increase in concentration of a persistent pollutant at successively higher trophic levels.
Cartão 927
Pergunta
What is rewilding?
Resposta
Ecosystem restoration that rebuilds natural processes, species interactions, and self-sustaining ecological function.
Cartão 928
Pergunta
What features can make an ecosystem more stable?
Resposta
Diverse functional roles, connected habitats, intact food webs, nutrient cycling, and balancing feedbacks can help the system resist or recover from disturbance.
Cartão 929
Pergunta
Which term describes nutrient enrichment that can deplete oxygen in water?
Resposta
eutrophication
Cartão 930
Pergunta
Which term describes increasing pollutant concentration up a food chain?
Resposta
biomagnification
Cartão 931
Pergunta
Which term describes restoration focused on natural processes and self-sustaining ecosystems?
Resposta
rewilding
Cartão 932
Pergunta
How could extensive Amazon deforestation push the ecosystem toward a tipping point?
Resposta
Loss of trees can reduce rainfall recycling and increase heat and fire, which cause further forest loss and may shift large areas toward a drier state.
Cartão 933
Pergunta
What are a benefit and a limitation of using a mesocosm?
Resposta
It allows controlled experiments with interacting organisms, but its simplified scale cannot reproduce every process or long-term influence in a natural ecosystem.
Cartão 934
Pergunta
Why should a fishery harvest below an uncertain maximum sustainable yield?
Resposta
Population estimates and recruitment vary, so a safety margin reduces the chance that error or a poor breeding year drives long-term decline.
Cartão 935
Pergunta
How can intensive agriculture reduce ecosystem stability?
Resposta
Habitat loss, low crop diversity, soil degradation, heavy water use, pesticides, and nutrient runoff can weaken food webs and ecosystem processes.
Cartão 936
Pergunta
Why can microplastic pollution harm aquatic ecosystems?
Resposta
Small persistent particles can be ingested, carry additives or other pollutants, damage feeding and tissues, and move through food webs.
Cartão 937
Pergunta
How can rewilding improve ecosystem stability?
Resposta
Restoring native species, habitat connections, and natural disturbance or grazing processes can rebuild feedbacks and allow the ecosystem to maintain itself with less intervention.
Cartão 938
Pergunta
What is the greenhouse effect?
Resposta
Warming caused when atmospheric gases absorb and re-emit outgoing infrared radiation.
Cartão 939
Pergunta
What is a greenhouse gas?
Resposta
An atmospheric gas that absorbs infrared radiation at wavelengths emitted by Earth.
Cartão 940
Pergunta
What is carbon dioxide (CO₂)?
Resposta
A long-lived greenhouse gas increased mainly by fossil-fuel combustion, cement production, and land-use change.
Cartão 941
Pergunta
What is methane (CH₄)?
Resposta
A potent greenhouse gas emitted by sources including fossil-fuel systems, livestock, rice cultivation, wetlands, and waste.
Cartão 942
Pergunta
Which term describes warming from absorption and re-emission of infrared radiation?
Resposta
the greenhouse effect
Cartão 943
Pergunta
Which term describes an atmospheric infrared-absorbing gas?
Resposta
a greenhouse gas
Cartão 944
Pergunta
Which term describes the long-lived greenhouse gas strongly increased by fossil fuels?
Resposta
carbon dioxide (CO₂)
Cartão 945
Pergunta
Which term describes the potent short-lived greenhouse gas from biological and fossil sources?
Resposta
methane (CH₄)
Cartão 946
Pergunta
What is albedo?
Resposta
The fraction of incoming radiation reflected by a surface.
Cartão 947
Pergunta
What is a carbon sink?
Resposta
A reservoir that absorbs more carbon than it releases over a specified period.
Cartão 948
Pergunta
What is ocean acidification?
Resposta
Decline in seawater pH caused mainly by absorption of human-emitted carbon dioxide.
Cartão 949
Pergunta
What is climate change?
Resposta
A persistent change in the statistical patterns of climate over decades or longer.
Cartão 950
Pergunta
Which term describes surface reflectivity?
Resposta
albedo
Cartão 951
Pergunta
Which term describes a reservoir with net carbon uptake?
Resposta
a carbon sink
Cartão 952
Pergunta
Which term describes seawater pH decline from absorbed carbon dioxide?
Resposta
ocean acidification
Cartão 953
Pergunta
Which term describes long-term change in climate patterns?
Resposta
climate change
Cartão 954
Pergunta
What is the enhanced greenhouse effect?
Resposta
Additional warming caused by human-driven increases in greenhouse-gas concentrations.
Cartão 955
Pergunta
How do climate mitigation and climate adaptation differ?
Resposta
Mitigation limits the magnitude of climate change; adaptation reduces harm from changes that occur.
Cartão 956
Pergunta
How does increasing greenhouse-gas concentration alter Earth's energy balance?
Resposta
Less outgoing infrared energy initially escapes to space, so the climate warms until energy balance is restored at a higher temperature.
Cartão 957
Pergunta
How can melting ice amplify warming?
Resposta
Less bright ice lowers albedo, so darker land or water absorbs more solar energy and causes further warming.
Cartão 958
Pergunta
How can climate change alter species distributions?
Resposta
Temperature, rainfall, seasons, sea level, and interactions shift, moving or shrinking areas with suitable conditions.
Cartão 959
Pergunta
Why can ocean acidification harm calcifying organisms?
Resposta
Carbonate chemistry changes, reducing availability of carbonate ions used to build calcium-carbonate structures.
Cartão 960
Pergunta
How can ecosystem protection contribute to climate mitigation?
Resposta
Protecting forests, wetlands, soils, and coastal habitats can avoid emissions and maintain or increase carbon storage.
960 cartões
IB Biology SL Flashcards: Complete Course Review
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