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