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