AP Biology Flashcards: Complete 8-Unit Course Review
Review all 8 AP Biology units with original flashcards for concepts, pathways, experimental design, data interpretation, and FRQ reasoning.
Over dit deck
AP Biology Flashcards: Complete 8-Unit Course Review
The current AP Biology framework covers eight units, from chemistry of life through ecology. This 540-card deck turns that full course into short, original retrieval prompts, with science-practice reasoning mixed into the biology instead of parked in a separate section.
What the cards practice
The cards connect terms to functions, structures to consequences, pathway steps to inputs, outputs, locations, and regulation, and evidence to biological claims. Separate prompts cover useful reverse mappings when they are real study tasks—for example, identifying a process from its location or choosing the inference supported by a result. Short original scenarios also practice describing patterns, explaining mechanisms, predicting changes, justifying claims, setting up calculations, and evaluating evidence.
The deck does not mechanically reverse every definition or pathway. It leaves out copied exam material, scoring language, official figures, exhaustive protocols, broad essay prompts, textbook-specific trivia, and advanced-college details outside the current course boundary.
Learning order
The sequence follows Units 1–8. Within each unit it moves from prerequisites to processes, applications, experiments, data, and FRQ-style reasoning, while spacing close variants apart. Long-term spacing and interleaving are left to the review scheduler.
What still needs practice
Flashcards are useful for recall and small reasoning moves, but they cannot replace laboratory work, graph construction, extended data analysis, or timed multiple-choice and free-response practice. Use the deck beside class labs and full original practice questions.
Scope and provenance
The course boundary was reviewed on September 1, 2026 against the College Board AP Biology course page, the Fall 2025 Course and Exam Description, its current clarifications and corrections, the 2026–27 course-change table, and the current exam page. The selection, prompts, answers, examples, sequence, metadata, and cover are independently created from common biological knowledge and source checks. No exam questions, scoring guidelines, CED text, answer keys, or official figures were copied or transformed.
The Common knowledge · CC0 1.0 label applies to the original wording, organization, metadata, and generated media to the extent applicable rights exist. It does not claim ownership of biological facts, AP or College Board names, or third-party source material.
This independent, unofficial study deck is not affiliated with, endorsed by, or sponsored by College Board. AP and College Board names identify the course and exam only. Official requirements: https://apcentral.collegeboard.org/courses/ap-biology
Kaarten in dit deck
Kaart 1
Vraag
Why is a water molecule polar?
Antwoord
Oxygen pulls shared electrons more strongly than hydrogen, giving oxygen a partial negative charge and the hydrogens partial positive charges.
Kaart 2
Vraag
Which elements make up most biological molecules?
Antwoord
Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur—often shortened to CHNOPS.
Kaart 3
Vraag
What is the relationship between a monomer and a polymer?
Antwoord
Monomers are small building blocks; polymers are chains or networks made from repeated monomers.
Kaart 4
Vraag
What is a monosaccharide's main role in cells?
Antwoord
It can provide quick energy and serve as a building block for larger carbohydrates.
Kaart 5
Vraag
Why do lipids mix poorly with water?
Antwoord
Most of their bonds are nonpolar, so water cannot form favorable interactions with them.
Kaart 6
Vraag
What three parts make up a nucleotide?
Antwoord
A five-carbon sugar, a phosphate group, and a nitrogenous base.
Kaart 7
Vraag
What parts of an amino acid vary and stay constant?
Antwoord
The amino group, carboxyl group, hydrogen, and central carbon are shared; the side chain, or R group, varies.
Kaart 8
Vraag
What does pH measure?
Antwoord
The negative logarithm of hydrogen-ion concentration; lower pH means more hydrogen ions.
Kaart 9
Vraag
What is a hydrogen bond in liquid water?
Antwoord
A weak attraction between a partially positive hydrogen on one water molecule and a partially negative oxygen on another.
Kaart 10
Vraag
How does an unsaturated fatty acid differ from a saturated one?
Antwoord
An unsaturated fatty acid has at least one carbon–carbon double bond; a saturated fatty acid has none.
Kaart 11
Vraag
What bond links amino acids in a polypeptide?
Antwoord
A peptide bond.
Kaart 12
Vraag
What does dehydration synthesis do?
Antwoord
It joins subunits with a covalent bond while removing the elements of water.
Kaart 13
Vraag
How does cohesion help water move through a plant?
Antwoord
Hydrogen bonds keep water molecules linked, helping a continuous column rise through xylem.
Kaart 14
Vraag
How do plants and animals differ in short-term glucose storage?
Antwoord
Plants store glucose mainly as starch; animals store it mainly as glycogen.
Kaart 15
Vraag
What determines a protein's primary structure?
Antwoord
Its amino-acid sequence.
Kaart 16
Vraag
How does a cis double bond affect a fatty-acid tail?
Antwoord
It introduces a bend that prevents neighboring tails from packing tightly.
Kaart 17
Vraag
How does adhesion support water transport in narrow tubes?
Antwoord
Water sticks to polar surfaces, helping it resist gravity along cell walls.
Kaart 18
Vraag
Which base pairing distinguishes RNA from DNA?
Antwoord
RNA uses uracil, so adenine pairs with uracil instead of thymine.
Kaart 19
Vraag
What stabilizes common protein secondary structures?
Antwoord
Hydrogen bonds between atoms in the polypeptide backbone.
Kaart 20
Vraag
Why can carbon form so many biological structures?
Antwoord
It has four valence electrons and can form four stable covalent bonds, including chains, branches, and rings.
Kaart 21
Vraag
Why can some insects stand on water?
Antwoord
Cohesion among surface water molecules creates high surface tension.
Kaart 22
Vraag
What does hydrolysis do to a biological polymer?
Antwoord
It adds the elements of water to break a covalent bond between subunits.
Kaart 23
Vraag
What carbohydrate strengthens plant cell walls?
Antwoord
Cellulose.
Kaart 24
Vraag
Why are fats useful for long-term energy storage?
Antwoord
Their many C–H bonds store substantial chemical energy, and hydrophobic storage adds little water mass.
Kaart 25
Vraag
How does water buffer rapid temperature change?
Antwoord
Breaking and forming many hydrogen bonds absorbs or releases substantial heat, giving water a high specific heat.
Kaart 26
Vraag
What does antiparallel mean for a DNA double helix?
Antwoord
Its two strands run in opposite directions: one 5′→3′ and the other 3′→5′.
Kaart 27
Vraag
What mainly drives a protein's tertiary structure?
Antwoord
Interactions among side chains, including hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.
Kaart 28
Vraag
What is a trace element?
Antwoord
An element an organism needs in very small amounts, such as iron in many electron-transfer proteins.
Kaart 29
Vraag
Why does sweating cool an organism?
Antwoord
The fastest water molecules escape as vapor, carrying heat away from the surface.
Kaart 30
Vraag
A cell builds a polysaccharide from sugars. Is water consumed or released?
Antwoord
Released. Forming each linkage by dehydration removes water.
Kaart 31
Vraag
Why can branching help a storage polysaccharide release glucose quickly?
Antwoord
More branch ends give enzymes more sites to work at once.
Kaart 32
Vraag
What makes a phospholipid amphipathic?
Antwoord
It has a polar, hydrophilic head and nonpolar, hydrophobic tails.
Kaart 33
Vraag
Where is biological information encoded in a nucleic acid?
Antwoord
In the linear sequence of nucleotide bases.
Kaart 34
Vraag
What is quaternary protein structure?
Antwoord
The arrangement of two or more polypeptide subunits into one functional protein.
Kaart 35
Vraag
Why does ice float on liquid water?
Antwoord
Stable hydrogen bonds hold ice molecules in an open lattice, making ice less dense than liquid water.
Kaart 36
Vraag
How does electronegativity affect a covalent bond?
Antwoord
A difference in attraction for electrons makes electron sharing unequal and can create a polar bond.
Kaart 37
Vraag
A digestive reaction adds water while splitting a macromolecule. What reaction is this?
Antwoord
Hydrolysis.
Kaart 38
Vraag
What links monosaccharides in a polysaccharide?
Antwoord
Glycosidic covalent bonds.
Kaart 39
Vraag
Why do phospholipids form bilayers in water?
Antwoord
Hydrophilic heads face water while hydrophobic tails cluster away from it.
Kaart 40
Vraag
To which end are nucleotides added during nucleic-acid synthesis?
Antwoord
The 3′ end of the growing strand.
Kaart 41
Vraag
Why can one amino-acid substitution change protein function?
Antwoord
It can alter side-chain interactions, folding, stability, or an active or binding site.
Kaart 42
Vraag
How does a buffer resist a pH change?
Antwoord
It can accept added hydrogen ions or donate them when hydrogen-ion concentration falls.
Kaart 43
Vraag
Why is water a useful solvent for cells?
Antwoord
Its partial charges surround ions and other polar molecules, separating and dispersing them.
Kaart 44
Vraag
Why do functional groups matter in organic molecules?
Antwoord
They give carbon skeletons predictable chemical properties, such as polarity, acidity, or reactivity.
Kaart 45
Vraag
Why can two polymers built from similar monomers have different functions?
Antwoord
Their monomer sequence, branching, length, and three-dimensional shape can differ.
Kaart 46
Vraag
A seedling consumes stored starch. What happens to the starch?
Antwoord
Hydrolysis breaks it into smaller sugars that can enter energy pathways.
Kaart 47
Vraag
What are two biological roles of steroids?
Antwoord
Some act as signaling molecules, and cholesterol helps stabilize animal cell membranes.
Kaart 48
Vraag
What bond forms the backbone of a nucleic-acid strand?
Antwoord
Covalent phosphodiester bonds link the sugar of one nucleotide to the phosphate of the next.
Kaart 49
Vraag
What does denaturation do to a protein?
Antwoord
It disrupts the protein's three-dimensional shape and often its function without usually breaking the primary peptide chain.
Kaart 50
Vraag
An enzyme works best near pH 7 but slows at pH 3. What is a likely explanation?
Antwoord
Extra hydrogen ions changed charges and interactions that maintain the enzyme's active shape.
Kaart 51
Vraag
What structure encloses every cell?
Antwoord
A plasma membrane.
Kaart 52
Vraag
What is the nucleus's main function?
Antwoord
It houses most eukaryotic DNA and is a major site of DNA replication and transcription.
Kaart 53
Vraag
Why does surface-area-to-volume ratio fall as a cell grows?
Antwoord
Volume increases with the cube of length, while surface area increases with the square.
Kaart 54
Vraag
What does the fluid mosaic model describe?
Antwoord
A dynamic phospholipid bilayer containing mobile proteins, sterols, and carbohydrates.
Kaart 55
Vraag
What drives simple diffusion?
Antwoord
Random molecular motion produces net movement from higher to lower concentration.
Kaart 56
Vraag
How does active transport differ from facilitated diffusion?
Antwoord
Active transport moves a substance against its gradient using energy; facilitated diffusion moves it down a gradient.
Kaart 57
Vraag
Why does compartmentalization increase cellular efficiency?
Antwoord
It concentrates enzymes and substrates and maintains distinct conditions for different reactions.
Kaart 58
Vraag
When should a light microscope be preferred over an electron microscope?
Antwoord
When observing living cells or dynamic processes at lower resolution.
Kaart 59
Vraag
What does the nucleolus produce?
Antwoord
Ribosomal RNA and early ribosome subunits.
Kaart 60
Vraag
Does passive transport require direct cellular energy?
Antwoord
No. It moves substances down an electrochemical or concentration gradient.
Kaart 61
Vraag
What feature separates prokaryotic from eukaryotic cells?
Antwoord
Eukaryotic cells have a membrane-bound nucleus and other membrane-bound organelles; prokaryotic cells do not.
Kaart 62
Vraag
Which membrane region blocks most ions and polar molecules?
Antwoord
The hydrophobic interior formed by phospholipid tails.
Kaart 63
Vraag
What happens on rough endoplasmic reticulum?
Antwoord
Bound ribosomes make proteins for secretion, membranes, or the endomembrane system.
Kaart 64
Vraag
How does facilitated diffusion differ from simple diffusion?
Antwoord
It uses a channel or carrier protein but still moves a substance down its gradient.
Kaart 65
Vraag
Where is prokaryotic DNA usually located?
Antwoord
In a nucleoid region rather than inside a membrane-bound nucleus.
Kaart 66
Vraag
How does cholesterol affect an animal membrane?
Antwoord
It buffers fluidity, limiting excess movement when warm and preventing tight packing when cool.
Kaart 67
Vraag
What does smooth endoplasmic reticulum do?
Antwoord
It synthesizes lipids, detoxifies some compounds, and stores calcium in specialized cells.
Kaart 68
Vraag
What determines a channel protein's selectivity?
Antwoord
Its pore size, shape, charge, and gating behavior.
Kaart 69
Vraag
What does the sodium–potassium pump accomplish?
Antwoord
Using ATP, it exports three sodium ions and imports two potassium ions per cycle.
Kaart 70
Vraag
What do ribosomes do in both prokaryotic and eukaryotic cells?
Antwoord
They translate mRNA into polypeptides.
Kaart 71
Vraag
What is the Golgi apparatus's role?
Antwoord
It modifies, sorts, and packages proteins and lipids arriving from the endoplasmic reticulum.
Kaart 72
Vraag
What is osmosis?
Antwoord
Net movement of water across a selectively permeable membrane toward lower free-water concentration.
Kaart 73
Vraag
Why does a high surface-area-to-volume ratio help a cell?
Antwoord
It provides more membrane area per unit of cytoplasm for exchange with the environment.
Kaart 74
Vraag
How do unsaturated phospholipid tails affect membrane fluidity?
Antwoord
Their bends reduce tight packing, usually increasing fluidity.
Kaart 75
Vraag
Trace a secreted protein after translation begins.
Antwoord
Rough ER → transport vesicle → Golgi → secretory vesicle → plasma membrane.
Kaart 76
Vraag
What happens to an animal cell in a hypotonic solution?
Antwoord
Water enters; the cell swells and may lyse.
Kaart 77
Vraag
What is cotransport?
Antwoord
The downhill movement of one substance powers the uphill transport of another through the same protein.
Kaart 78
Vraag
What is the main role of a cell wall?
Antwoord
It provides structural support and helps prevent excessive expansion.
Kaart 79
Vraag
What do lysosomes do?
Antwoord
Their hydrolytic enzymes digest macromolecules and recycle damaged cell parts in an acidic compartment.
Kaart 80
Vraag
What happens to an animal cell in a hypertonic solution?
Antwoord
Water leaves; the cell shrinks.
Kaart 81
Vraag
How do intestinal microvilli improve absorption?
Antwoord
They increase membrane surface area without greatly increasing cell volume.
Kaart 82
Vraag
What can an integral membrane protein do?
Antwoord
It can transport substances, receive signals, catalyze reactions, or anchor cell structures.
Kaart 83
Vraag
What is a central vacuole's major role in a plant cell?
Antwoord
It stores solutes and water and helps maintain turgor pressure.
Kaart 84
Vraag
What happens to a plant cell in a hypotonic solution?
Antwoord
Water enters and turgor pressure rises; the cell wall helps prevent bursting.
Kaart 85
Vraag
How can a proton gradient power sucrose uptake in a plant cell?
Antwoord
Protons flow down their gradient through a symporter that carries sucrose uphill.
Kaart 86
Vraag
What evidence supports the endosymbiotic origin of mitochondria?
Antwoord
They have double membranes, circular DNA, bacterial-like ribosomes, and divide independently by a similar process.
Kaart 87
Vraag
Which overall energy-conversion pathway mainly occurs in mitochondria?
Antwoord
Most stages of aerobic cellular respiration and ATP production.
Kaart 88
Vraag
What happens to a plant cell in a hypertonic solution?
Antwoord
Water leaves, turgor falls, and the membrane may pull from the wall during plasmolysis.
Kaart 89
Vraag
Why can't a standard light microscope resolve a ribosome clearly?
Antwoord
A ribosome is smaller than the microscope's diffraction-limited resolution.
Kaart 90
Vraag
How do bacterial and plant cell walls differ?
Antwoord
Bacterial walls usually contain peptidoglycan; plant walls contain cellulose.
Kaart 91
Vraag
Which overall energy-conversion pathway occurs in chloroplasts?
Antwoord
Photosynthesis: converting light energy into chemical energy and fixing carbon.
Kaart 92
Vraag
A cubical cell doubles each side length. How do surface area and volume change?
Antwoord
Surface area increases 4-fold; volume increases 8-fold.
Kaart 93
Vraag
What is the role of membrane carbohydrates?
Antwoord
They help cells recognize and interact with one another.
Kaart 94
Vraag
What is water potential?
Antwoord
A measure predicting water movement; water moves from higher to lower water potential.
Kaart 95
Vraag
How do microtubules support a cell?
Antwoord
They resist compression, form tracks for motors, and build structures such as spindles, cilia, and flagella.
Kaart 96
Vraag
What is endocytosis?
Antwoord
The plasma membrane folds inward to bring material into the cell in a vesicle.
Kaart 97
Vraag
What evidence supports the endosymbiotic origin of chloroplasts?
Antwoord
They share bacterial-like DNA, ribosomes, division, and a double membrane consistent with engulfment.
Kaart 98
Vraag
In a membrane-permeability test, what is the independent variable?
Antwoord
The factor deliberately changed, such as temperature or solute identity.
Kaart 99
Vraag
How do microfilaments support cell movement?
Antwoord
Actin filaments interact with motor proteins to change cell shape, contract, and move materials.
Kaart 100
Vraag
What does the cytosol contain?
Antwoord
Water, ions, small molecules, and proteins where many metabolic reactions occur.
Kaart 101
Vraag
Why can diffusion limit cell size?
Antwoord
As dimensions grow, molecules must travel farther, while exchange area does not keep pace with metabolic volume.
Kaart 102
Vraag
What does selective permeability mean?
Antwoord
The membrane allows some substances to cross more readily than others.
Kaart 103
Vraag
What is an intermediate filament's general role?
Antwoord
It provides durable mechanical strength and helps anchor structures.
Kaart 104
Vraag
How does adding a nonpenetrating solute affect water potential?
Antwoord
It makes solute potential, and usually total water potential, more negative.
Kaart 105
Vraag
What is exocytosis?
Antwoord
A vesicle fuses with the plasma membrane and releases contents outside the cell.
Kaart 106
Vraag
Why can lysosomal enzymes digest safely inside a cell?
Antwoord
A membrane isolates the acidic enzymes from most cytosolic components.
Kaart 107
Vraag
Why include an untreated membrane sample in an experiment?
Antwoord
It provides a control baseline for judging the treatment's effect.
Kaart 108
Vraag
Why doesn't cell size alone identify whether a cell is prokaryotic?
Antwoord
Sizes overlap; the presence or absence of internal membrane-bound structures is stronger evidence.
Kaart 109
Vraag
Why are organelle interactions important?
Antwoord
Cell functions often require products to move through several specialized compartments rather than one organelle working alone.
Kaart 110
Vraag
What graph would show a size constraint clearly?
Antwoord
Plot cell size on the x-axis and surface-area-to-volume ratio on the y-axis; the ratio should decline as size rises.
Kaart 111
Vraag
Which molecules cross a phospholipid bilayer most easily without proteins?
Antwoord
Small nonpolar molecules, such as oxygen and carbon dioxide.
Kaart 112
Vraag
Two solutions have equal water potential. What is the net water movement?
Antwoord
None, although water molecules still move both ways.
Kaart 113
Vraag
Why is ATP loss likely to disrupt ion balance?
Antwoord
ATP-powered pumps stop maintaining gradients, so passive leaks move ions toward equilibrium.
Kaart 114
Vraag
How does folding an internal membrane help an organelle?
Antwoord
It increases surface area for membrane-bound reactions without a matching increase in volume.
Kaart 115
Vraag
A dye leaves heated cells faster than unheated cells. What conclusion is supported?
Antwoord
Heating increased membrane permeability under the tested conditions; the data alone do not identify the exact molecular damage.
Kaart 116
Vraag
What does an enzyme change in a reaction?
Antwoord
It lowers activation energy, increasing reaction rate without changing the reaction's overall free-energy change.
Kaart 117
Vraag
What makes a reaction exergonic?
Antwoord
It releases free energy and has a negative change in free energy under the stated conditions.
Kaart 118
Vraag
What are the overall inputs and outputs of photosynthesis?
Antwoord
Carbon dioxide and water use light energy to produce carbohydrate and oxygen.
Kaart 119
Vraag
What are the overall reactants and products of aerobic cellular respiration?
Antwoord
Organic fuel and oxygen are converted mainly to carbon dioxide, water, and ATP, with heat released.
Kaart 120
Vraag
How should reaction rate be calculated from product data?
Antwoord
Divide the change in product amount by the elapsed time.
Kaart 121
Vraag
What makes an enzyme substrate-specific?
Antwoord
The active site's shape and chemical properties favor particular substrates.
Kaart 122
Vraag
Where do the light reactions occur?
Antwoord
In the thylakoid membranes of chloroplasts.
Kaart 123
Vraag
Where does glycolysis occur?
Antwoord
In the cytosol.
Kaart 124
Vraag
What makes a reaction endergonic?
Antwoord
It requires a net input of free energy and has a positive change in free energy.
Kaart 125
Vraag
What is induced fit?
Antwoord
Substrate binding shifts the enzyme's shape into a form that better supports catalysis.
Kaart 126
Vraag
Where does the Calvin cycle occur?
Antwoord
In the chloroplast stroma.
Kaart 127
Vraag
What does glycolysis produce per glucose?
Antwoord
Two pyruvate, a net two ATP, and two NADH.
Kaart 128
Vraag
How can cells drive an endergonic reaction?
Antwoord
They couple it to a sufficiently exergonic reaction so the combined free-energy change is negative.
Kaart 129
Vraag
Why isn't an enzyme consumed by the reaction it catalyzes?
Antwoord
It returns to a reusable form after products leave the active site.
Kaart 130
Vraag
What do photosynthetic pigments do?
Antwoord
They absorb particular wavelengths and transfer excitation energy into the light reactions.
Kaart 131
Vraag
Does glycolysis require oxygen directly?
Antwoord
No. It can run without oxygen if NAD⁺ is regenerated.
Kaart 132
Vraag
What does ATP hydrolysis commonly provide?
Antwoord
Usable free energy and a phosphate group that can change a molecule's reactivity or protein shape.
Kaart 133
Vraag
How does substrate concentration affect rate at low concentrations?
Antwoord
Rate usually rises because more substrate molecules collide with available active sites.
Kaart 134
Vraag
Why do chlorophyll-containing leaves reflect green light?
Antwoord
Chlorophyll absorbs green wavelengths less strongly than red and blue wavelengths.
Kaart 135
Vraag
Where does pyruvate oxidation occur in a eukaryotic cell?
Antwoord
In the mitochondrial matrix.
Kaart 136
Vraag
Why is ATP called an energy-coupling molecule?
Antwoord
Its hydrolysis links energy-releasing processes to cellular work.
Kaart 137
Vraag
Why does enzyme rate plateau at high substrate concentration?
Antwoord
Most active sites are occupied, so enzyme amount becomes limiting.
Kaart 138
Vraag
What is photolysis of water?
Antwoord
Light-driven splitting of water that supplies electrons and protons and releases oxygen.
Kaart 139
Vraag
What happens during pyruvate oxidation?
Antwoord
Each pyruvate becomes acetyl-CoA, releasing carbon dioxide and reducing NAD⁺ to NADH.
Kaart 140
Vraag
Why measure an initial enzyme rate?
Antwoord
Substrate depletion and product buildup have had less time to distort the rate.
Kaart 141
Vraag
How can high temperature reduce enzyme activity?
Antwoord
Heat can disrupt interactions that maintain the enzyme's functional shape.
Kaart 142
Vraag
What is photosystem II's key contribution?
Antwoord
It excites electrons and replaces them by oxidizing water.
Kaart 143
Vraag
Where does the citric acid cycle occur in eukaryotes?
Antwoord
In the mitochondrial matrix.
Kaart 144
Vraag
What is oxidation?
Antwoord
Loss of electrons, often accompanied by loss of hydrogen or gain of oxygen.
Kaart 145
Vraag
Why does each enzyme have an optimal pH range?
Antwoord
pH changes charges on amino-acid side chains and can alter binding or folding.
Kaart 146
Vraag
What does the photosynthetic electron transport chain build?
Antwoord
A proton gradient across the thylakoid membrane.
Kaart 147
Vraag
What is the citric acid cycle's main energy role?
Antwoord
It oxidizes acetyl groups and transfers electrons to NADH and FADH₂, making a small amount of ATP.
Kaart 148
Vraag
In a photosynthesis experiment, why keep leaf area constant?
Antwoord
Leaf area affects light capture and gas exchange, so changing it could confound the tested factor.
Kaart 149
Vraag
How does a competitive inhibitor reduce enzyme activity?
Antwoord
It competes with substrate for the active site.
Kaart 150
Vraag
How does chloroplast ATP synthase make ATP?
Antwoord
Protons flow from the thylakoid space to the stroma through ATP synthase, driving phosphorylation of ADP.
Kaart 151
Vraag
Where is the respiratory electron transport chain located in eukaryotes?
Antwoord
In the inner mitochondrial membrane.
Kaart 152
Vraag
What is reduction?
Antwoord
Gain of electrons, often accompanied by gain of hydrogen or loss of oxygen.
Kaart 153
Vraag
How can extra substrate weaken competitive inhibition?
Antwoord
More substrate increases the chance that substrate, rather than inhibitor, occupies the active site.
Kaart 154
Vraag
What is photosystem I's key contribution?
Antwoord
It re-energizes electrons used to reduce NADP⁺ to NADPH.
Kaart 155
Vraag
What is oxygen's role in aerobic respiration?
Antwoord
It is the final electron acceptor and combines with electrons and protons to form water.
Kaart 156
Vraag
A respiration graph gets steeper after temperature rises. What does the slope show?
Antwoord
A higher rate of the measured respiratory change, such as oxygen consumption per unit time.
Kaart 157
Vraag
How does a noncompetitive inhibitor act?
Antwoord
It binds away from the active site and changes enzyme activity, often by altering shape.
Kaart 158
Vraag
What products of the light reactions feed the Calvin cycle?
Antwoord
ATP and NADPH.
Kaart 159
Vraag
How does electron transport create a proton gradient?
Antwoord
Released electron energy pumps protons from the matrix to the intermembrane space.
Kaart 160
Vraag
What do NADH and FADH₂ carry?
Antwoord
High-energy electrons and associated hydrogen used in energy-transfer pathways.
Kaart 161
Vraag
What is allosteric regulation?
Antwoord
A regulator binds at one site and changes activity at another site on the protein.
Kaart 162
Vraag
What does carbon fixation accomplish?
Antwoord
It incorporates inorganic carbon dioxide into an organic molecule.
Kaart 163
Vraag
What is oxidative phosphorylation?
Antwoord
ATP production powered by electron transport and chemiosmosis.
Kaart 164
Vraag
Why use multiple biological replicates in a rate experiment?
Antwoord
They reveal natural variation and make the estimated treatment effect more reliable.
Kaart 165
Vraag
What is fermentation's central purpose?
Antwoord
It regenerates NAD⁺ so glycolysis can continue without an active electron transport chain.
Kaart 166
Vraag
How does feedback inhibition control a pathway?
Antwoord
A pathway's end product inhibits an earlier enzyme, reducing unnecessary production.
Kaart 167
Vraag
What enzyme fixes carbon in the Calvin cycle?
Antwoord
Rubisco.
Kaart 168
Vraag
How does mitochondrial ATP synthase make ATP?
Antwoord
Protons flow into the matrix through ATP synthase, driving ADP phosphorylation.
Kaart 169
Vraag
Why do cells use stepwise electron transfers?
Antwoord
They release energy in manageable increments that can be captured instead of lost mostly as heat.
Kaart 170
Vraag
What is a cofactor?
Antwoord
A nonprotein helper, often a metal ion or small organic coenzyme, required for some enzymes to function.
Kaart 171
Vraag
What are the three broad phases of the Calvin cycle?
Antwoord
Carbon fixation, reduction, and regeneration of the carbon-dioxide acceptor RuBP.
Kaart 172
Vraag
How does lactic-acid fermentation regenerate NAD⁺?
Antwoord
NADH reduces pyruvate to lactate, returning electrons to form NAD⁺.
Kaart 173
Vraag
What is substrate-level phosphorylation?
Antwoord
An enzyme transfers a phosphate directly from an intermediate to ADP.
Kaart 174
Vraag
Error bars overlap broadly between two treatments. What is a careful conclusion?
Antwoord
The graph alone does not show a clear difference; a suitable statistical analysis and design context are still needed.
Kaart 175
Vraag
Why run an enzyme assay without enzyme?
Antwoord
It measures the uncatalyzed background change and tests whether enzyme is required.
Kaart 176
Vraag
How does alcoholic fermentation regenerate NAD⁺?
Antwoord
Pyruvate loses carbon dioxide, and the remaining compound is reduced to ethanol as NADH becomes NAD⁺.
Kaart 177
Vraag
What is G3P's role in photosynthesis?
Antwoord
It is a three-carbon product that can leave the Calvin cycle and help build carbohydrates.
Kaart 178
Vraag
Why are mitochondrial cristae useful?
Antwoord
They increase inner-membrane area for electron transport chains and ATP synthase.
Kaart 179
Vraag
What does phosphorylation often do to a molecule?
Antwoord
It adds a phosphate group that can increase reactivity or alter a protein's shape and activity.
Kaart 180
Vraag
A mutation lowers an enzyme's maximum rate but not substrate binding. What is a plausible effect?
Antwoord
It may impair a catalytic step or reduce the number of functional enzyme molecules.
Kaart 181
Vraag
Why must the Calvin cycle regenerate RuBP?
Antwoord
RuBP is the carbon-dioxide acceptor needed for another turn of fixation.
Kaart 182
Vraag
A chemical lowers oxygen use but not glycolysis. Which stage is most directly implicated?
Antwoord
Aerobic electron transport or a process supplying it, because glycolysis itself does not consume oxygen.
Kaart 183
Vraag
How would closed stomata affect photosynthesis?
Antwoord
Carbon dioxide entry falls, which can limit carbon fixation even when light is available.
Kaart 184
Vraag
A plant receives green light only. Predict its photosynthetic rate.
Antwoord
It will usually be lower than under equally intense red or blue light because common chlorophylls absorb green poorly.
Kaart 185
Vraag
Why does fermentation yield less ATP per glucose than aerobic respiration?
Antwoord
It relies on glycolysis alone and leaves much of glucose's chemical energy in reduced end products.
Kaart 186
Vraag
How does low ATP affect respiration pathway activity?
Antwoord
It usually relieves inhibition of key enzymes, increasing fuel oxidation and ATP production.
Kaart 187
Vraag
How can oxygen production estimate photosynthetic rate?
Antwoord
Oxygen is a light-reaction product, so its production per unit time can serve as a rate proxy under controlled conditions.
Kaart 188
Vraag
What happens to electron transport if oxygen is removed?
Antwoord
The chain backs up because electrons lack a final acceptor; NADH accumulates and oxidative phosphorylation stops.
Kaart 189
Vraag
Why does a light-response curve eventually level off?
Antwoord
Another factor, such as carbon dioxide supply, temperature, or enzyme capacity, becomes limiting.
Kaart 190
Vraag
An uncoupler lets protons cross the inner mitochondrial membrane. What happens?
Antwoord
The gradient weakens, ATP production falls, and more energy is released as heat even if electron transport continues.
Kaart 191
Vraag
What is direct-contact signaling?
Antwoord
A membrane-bound molecule or cell junction communicates with an adjacent cell.
Kaart 192
Vraag
What are the three broad stages of cell signaling?
Antwoord
Reception, transduction, and response.
Kaart 193
Vraag
How can a receptor mutation block a response even when ligand is present?
Antwoord
The receptor may fail to bind ligand, change shape, or activate the first relay protein.
Kaart 194
Vraag
What is negative feedback?
Antwoord
A response reduces the original stimulus, helping stabilize a variable near a functional range.
Kaart 195
Vraag
What happens during G1 phase?
Antwoord
The cell grows, performs normal functions, and prepares for DNA replication.
Kaart 196
Vraag
Cells show response values of 2, 7, and 18 after rising ligand doses. Describe the trend.
Antwoord
The response increases with ligand dose across the tested range.
Kaart 197
Vraag
What happens during reception?
Antwoord
A ligand binds its receptor and changes the receptor's activity or shape.
Kaart 198
Vraag
What is paracrine signaling?
Antwoord
A cell releases a local regulator that acts on nearby target cells.
Kaart 199
Vraag
What happens during S phase?
Antwoord
DNA is replicated, producing sister chromatids for each chromosome.
Kaart 200
Vraag
A response occurs without ligand. What pathway defect is plausible?
Antwoord
A receptor or downstream relay protein may be constitutively active.
Kaart 201
Vraag
What happens during signal transduction?
Antwoord
Intracellular steps relay and often amplify information from the activated receptor.
Kaart 202
Vraag
What is synaptic signaling?
Antwoord
A neuron releases neurotransmitter across a short synaptic gap to a target cell.
Kaart 203
Vraag
What happens during G2 phase?
Antwoord
The cell grows, checks replicated DNA, and prepares the machinery for division.
Kaart 204
Vraag
Why compare receptor-positive and receptor-negative cells?
Antwoord
The comparison tests whether the receptor is necessary for the observed response.
Kaart 205
Vraag
What counts as a cellular response?
Antwoord
A change in gene expression, enzyme activity, ion flow, secretion, movement, division, or another cell behavior.
Kaart 206
Vraag
How does insulin participate in negative feedback?
Antwoord
High blood glucose promotes insulin release, which lowers blood glucose and reduces the original stimulus.
Kaart 207
Vraag
What happens during mitosis?
Antwoord
A eukaryotic nucleus separates duplicated chromosomes into two nuclei.
Kaart 208
Vraag
What is endocrine signaling?
Antwoord
Hormones travel through circulatory fluid to target cells that may be far away.
Kaart 209
Vraag
What does a protein kinase do?
Antwoord
It transfers a phosphate from ATP to a target protein.
Kaart 210
Vraag
A drug blocks a kinase, and the final response disappears. What is supported?
Antwoord
The kinase is required somewhere in that pathway under the tested conditions.
Kaart 211
Vraag
What happens during cytokinesis?
Antwoord
The cytoplasm divides to form separate daughter cells.
Kaart 212
Vraag
How does glucagon participate in glucose homeostasis?
Antwoord
Low blood glucose promotes glucagon release, which raises blood glucose toward the normal range.
Kaart 213
Vraag
What does a protein phosphatase do?
Antwoord
It removes a phosphate group from a target protein.
Kaart 214
Vraag
What is a ligand?
Antwoord
A signaling molecule that binds specifically to a receptor.
Kaart 215
Vraag
What is the G1 checkpoint's broad role?
Antwoord
It checks size, nutrients, growth signals, and DNA condition before replication.
Kaart 216
Vraag
Why can't one inhibitor experiment prove a protein's exact pathway position?
Antwoord
Off-target effects and indirect dependencies can produce the same outcome.
Kaart 217
Vraag
Why are phosphorylation cascades reversible?
Antwoord
Kinases add phosphates, while phosphatases remove them and reset pathway components.
Kaart 218
Vraag
What is positive feedback?
Antwoord
A response strengthens the initiating stimulus until a separate event stops the loop.
Kaart 219
Vraag
What is the G2 checkpoint's broad role?
Antwoord
It checks whether DNA replication is complete and damage is repaired before mitosis.
Kaart 220
Vraag
Why don't all cells respond to the same hormone?
Antwoord
Only cells with a compatible receptor and response machinery can respond.
Kaart 221
Vraag
What is a second messenger?
Antwoord
A small intracellular molecule or ion that relays a signal after receptor activation.
Kaart 222
Vraag
How can rescue with an active downstream protein map a pathway?
Antwoord
If the response returns despite an upstream block, the rescued protein likely acts downstream of that block.
Kaart 223
Vraag
What does the spindle checkpoint verify?
Antwoord
Every chromosome is correctly attached to spindle microtubules before sister chromatids separate.
Kaart 224
Vraag
Why is blood clotting a positive-feedback process?
Antwoord
Activated platelets recruit and activate more platelets until the break is sealed.
Kaart 225
Vraag
Name two common second messengers.
Antwoord
Cyclic AMP and calcium ions.
Kaart 226
Vraag
A mutant receptor binds ligand but never becomes phosphorylated. Predict downstream signaling.
Antwoord
It will likely fall or disappear if receptor phosphorylation is required to recruit relay proteins.
Kaart 227
Vraag
How do cyclins regulate the cell cycle?
Antwoord
Their concentrations rise and fall, activating cyclin-dependent kinases at specific stages.
Kaart 228
Vraag
Why must DNA replicate before mitosis?
Antwoord
Each daughter nucleus needs a complete copy of the genome.
Kaart 229
Vraag
Where do receptors for many peptide hormones sit?
Antwoord
In the plasma membrane, because these polar ligands do not readily cross the lipid bilayer.
Kaart 230
Vraag
How can a signaling pathway amplify a weak signal?
Antwoord
One activated component activates many downstream molecules at successive steps.
Kaart 231
Vraag
What is the dependent variable in a ligand-dose experiment?
Antwoord
The measured response, such as reporter activity, enzyme phosphorylation, or ion concentration.
Kaart 232
Vraag
What do cyclin-dependent kinases do?
Antwoord
When paired with cyclins, they phosphorylate targets that drive cell-cycle transitions.
Kaart 233
Vraag
Why doesn't positive feedback usually maintain homeostasis by itself?
Antwoord
It drives change away from the starting state and needs an external stop.
Kaart 234
Vraag
What is a G protein's signaling role?
Antwoord
It switches activity when bound to GTP and relays information from certain membrane receptors to effectors.
Kaart 235
Vraag
How would you test whether calcium is required for a response?
Antwoord
Block the calcium rise while keeping other conditions matched, then compare the response with a vehicle control.
Kaart 236
Vraag
What is apoptosis?
Antwoord
Programmed cell death that dismantles a cell in a controlled way.
Kaart 237
Vraag
Where are receptors for many steroid hormones?
Antwoord
Inside the cell, where lipid-soluble hormones can bind after crossing the membrane.
Kaart 238
Vraag
How can an ion-channel receptor create a rapid response?
Antwoord
Ligand binding opens or closes a pore, quickly changing ion movement and membrane conditions.
Kaart 239
Vraag
Why test several ligand concentrations?
Antwoord
A dose–response series can reveal sensitivity, saturation, and whether effects scale with ligand.
Kaart 240
Vraag
Why is apoptosis useful in multicellular organisms?
Antwoord
It removes damaged, infected, or unneeded cells with limited harm to neighbors.
Kaart 241
Vraag
A thermostat-like pathway overshoots repeatedly. What defect is plausible?
Antwoord
Delayed sensing or response can make negative feedback correct too late.
Kaart 242
Vraag
How can an intracellular receptor affect gene expression?
Antwoord
The ligand–receptor complex can act directly or indirectly as a transcription regulator.
Kaart 243
Vraag
Cells lacking protein X divide despite DNA damage. Justify a checkpoint claim.
Antwoord
Protein X likely supports a DNA-damage checkpoint because its absence links damage with continued division; rescue or pathway tests would strengthen the claim.
Kaart 244
Vraag
What aligns at the metaphase plate?
Antwoord
Duplicated chromosomes attached to spindle microtubules from opposite poles.
Kaart 245
Vraag
How can failed checkpoints contribute to cancer?
Antwoord
Cells with damage or abnormal signals can keep dividing instead of pausing or dying.
Kaart 246
Vraag
How can gap junctions support communication?
Antwoord
They connect neighboring animal-cell cytoplasms so small molecules and ions can pass directly.
Kaart 247
Vraag
Why can the same ligand trigger different responses in two cell types?
Antwoord
The cells can express different receptors, relay proteins, targets, or genes.
Kaart 248
Vraag
Two pathways share one relay protein. What can happen if that protein is blocked?
Antwoord
Both responses may weaken, showing pathway crosstalk or a shared component.
Kaart 249
Vraag
During which mitotic stage do sister chromatids separate?
Antwoord
Anaphase.
Kaart 250
Vraag
What defines a malignant tumor?
Antwoord
Its cells invade surrounding tissue and may spread to distant sites.
Kaart 251
Vraag
How would loss of a feedback inhibitor affect a biosynthetic pathway?
Antwoord
The pathway may stay active and overproduce its end product.
Kaart 252
Vraag
What ends a signaling response?
Antwoord
Ligand removal, receptor inactivation, GTP hydrolysis, messenger breakdown, or dephosphorylation can shut it down.
Kaart 253
Vraag
A pathway diagram shows A activates B, and B inhibits C. Predict C after A activation.
Antwoord
C activity should decrease, assuming the shown links are the relevant controlling interactions.
Kaart 254
Vraag
A phosphatase that normally turns off an activated relay protein is inhibited. Predict the effect on that pathway.
Antwoord
Phosphorylated targets may stay active longer, extending or strengthening the response.
Kaart 255
Vraag
A drug prevents spindle formation. Where should the cycle stop?
Antwoord
At the spindle checkpoint before anaphase, because chromosomes cannot attach correctly.
Kaart 256
Vraag
What is the purpose of meiosis?
Antwoord
It produces haploid cells and reshuffles inherited alleles for sexual reproduction.
Kaart 257
Vraag
What is crossing over?
Antwoord
Exchange of corresponding DNA segments between nonsister chromatids of homologous chromosomes.
Kaart 258
Vraag
What does Mendel's law of segregation describe?
Antwoord
An individual's two alleles for a gene separate into different gametes.
Kaart 259
Vraag
Why do X-linked recessive traits often appear more frequently in XY individuals?
Antwoord
They have only one X chromosome, so one recessive allele on it can determine the phenotype.
Kaart 260
Vraag
What is incomplete dominance?
Antwoord
The heterozygote has a phenotype intermediate between the two homozygotes.
Kaart 261
Vraag
What does a chi-square goodness-of-fit test compare?
Antwoord
Observed category counts with counts expected under a stated model.
Kaart 262
Vraag
What is a homologous chromosome pair?
Antwoord
Two chromosomes carrying the same gene locations, one inherited from each parent, possibly with different alleles.
Kaart 263
Vraag
What does Mendel's law of independent assortment describe?
Antwoord
Alleles of genes on different chromosomes, or far apart on one chromosome, assort independently during gamete formation.
Kaart 264
Vraag
What is genetic linkage?
Antwoord
Genes close together on the same chromosome tend to be inherited together.
Kaart 265
Vraag
When does crossing over occur?
Antwoord
During prophase I after homologs pair.
Kaart 266
Vraag
How do sister chromatids differ from homologous chromosomes?
Antwoord
Sister chromatids are replicated copies of one chromosome; homologs are the maternal and paternal versions of the same chromosome type.
Kaart 267
Vraag
For Aa × Aa, what is the expected genotype ratio?
Antwoord
1 AA : 2 Aa : 1 aa.
Kaart 268
Vraag
How can linked genes produce recombinant offspring?
Antwoord
Crossing over can exchange DNA between the gene locations.
Kaart 269
Vraag
What is the usual null hypothesis for a Mendelian chi-square test?
Antwoord
Any difference between observed and expected counts is due to chance sampling under the proposed inheritance model.
Kaart 270
Vraag
What happens to homologous chromosomes in meiosis I?
Antwoord
They pair and then separate into different cells.
540 kaarten
AP Biology Flashcards: Complete 8-Unit Course Review
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Kaart 271
Vraag
For Aa × Aa with complete dominance, what is the expected phenotype ratio?
Antwoord
3 dominant phenotype : 1 recessive phenotype.
Kaart 272
Vraag
How does crossing over increase variation?
Antwoord
It creates chromosomes with new combinations of parental alleles.
Kaart 273
Vraag
What does recombination frequency estimate?
Antwoord
Relative distance between linked genes; higher frequency generally means greater separation, up to the 50% limit.
Kaart 274
Vraag
What happens to sister chromatids in meiosis II?
Antwoord
Their centromeres separate, and the chromatids move into different cells.
Kaart 275
Vraag
What rule finds the probability of either of two mutually exclusive outcomes?
Antwoord
Add their individual probabilities.
Kaart 276
Vraag
What is codominance?
Antwoord
Both alleles contribute distinct, detectable products or traits in the heterozygote.
Kaart 277
Vraag
How is a chi-square contribution calculated for one category?
Antwoord
Subtract expected from observed, square the difference, and divide by expected.
Kaart 278
Vraag
When do homologous chromosomes pair as tetrads?
Antwoord
During prophase I.
Kaart 279
Vraag
What rule finds the probability that independent events both occur?
Antwoord
Multiply their individual probabilities.
Kaart 280
Vraag
What is independent assortment?
Antwoord
Each homologous pair orients independently at metaphase I, producing many maternal–paternal chromosome combinations.
Kaart 281
Vraag
Why can't recombination frequency exceed 50%?
Antwoord
At 50%, recombinant and parental combinations are equally common and the genes behave as if unlinked.
Kaart 282
Vraag
What aligns at the metaphase I plate?
Antwoord
Homologous pairs, with each homolog attached toward an opposite pole.
Kaart 283
Vraag
What is a test cross?
Antwoord
Crossing an individual with a dominant phenotype to a homozygous recessive individual to infer the unknown genotype.
Kaart 284
Vraag
How can one gene have multiple alleles?
Antwoord
More than two allele forms can exist in the population, although one diploid individual carries at most two.
Kaart 285
Vraag
How are total chi-square and category contributions related?
Antwoord
Total chi-square is the sum of all category contributions.
Kaart 286
Vraag
What separates during anaphase I?
Antwoord
Homologous chromosomes; sister chromatids remain joined.
Kaart 287
Vraag
How does random fertilization increase variation?
Antwoord
Any one genetically varied gamete from one parent can fuse with any compatible gamete from the other.
Kaart 288
Vraag
A test cross yields about half recessive offspring. What genotype is supported for the unknown parent?
Antwoord
Heterozygous.
Kaart 289
Vraag
What is nondisjunction?
Antwoord
Failure of homologous chromosomes or sister chromatids to separate normally.
Kaart 290
Vraag
What aligns during metaphase II?
Antwoord
Individual duplicated chromosomes in each haploid cell.
Kaart 291
Vraag
What is polygenic inheritance?
Antwoord
Multiple genes contribute to one trait, often producing continuous phenotypic variation.
Kaart 292
Vraag
For a simple goodness-of-fit test, how are degrees of freedom found?
Antwoord
Number of categories minus one.
Kaart 293
Vraag
Which meiotic events create variation before fertilization?
Antwoord
Crossing over and independent assortment.
Kaart 294
Vraag
How does ploidy change during meiosis?
Antwoord
Homolog separation reduces diploid cells to haploid cells; meiosis II separates chromatids without another ploidy reduction.
Kaart 295
Vraag
What pedigree pattern often suggests a recessive trait?
Antwoord
Unaffected parents can have an affected child, if both parents carry the allele.
Kaart 296
Vraag
How can meiotic nondisjunction affect gametes?
Antwoord
It can produce gametes with an extra or missing chromosome.
Kaart 297
Vraag
What is pleiotropy?
Antwoord
One gene influences multiple phenotypic traits.
Kaart 298
Vraag
Why is there no second DNA replication before meiosis II?
Antwoord
The goal is to separate existing sister chromatids, not duplicate the genome again.
Kaart 299
Vraag
What does a p-value below the chosen threshold support?
Antwoord
Rejecting the null model because the observed deviation would be unlikely if that model were correct.
Kaart 300
Vraag
Why are siblings genetically different even with the same parents?
Antwoord
They inherit different allele combinations through crossing over, independent assortment, and random fertilization.
Kaart 301
Vraag
Why do small families often deviate from expected Mendelian ratios?
Antwoord
Probability ratios describe long-run expectations; random sampling variation is large with few offspring.
Kaart 302
Vraag
A diploid cell has six chromosomes. How many chromosomes should each normal meiotic product have?
Antwoord
Three.
Kaart 303
Vraag
A trisomic zygote forms after fertilization. What meiotic error is a likely cause?
Antwoord
Nondisjunction produced a gamete carrying an extra copy of that chromosome.
Kaart 304
Vraag
Why can identical genotypes show different phenotypes?
Antwoord
Environmental conditions and developmental variation can alter gene expression or trait development.
Kaart 305
Vraag
What does failing to reject a genetic null hypothesis mean?
Antwoord
The data do not show a significant departure from the model; they do not prove the model true.
Kaart 306
Vraag
How do DNA and RNA sugars differ?
Antwoord
DNA contains deoxyribose; RNA contains ribose.
Kaart 307
Vraag
What does semiconservative DNA replication produce?
Antwoord
Each daughter DNA molecule contains one original strand and one newly synthesized strand.
Kaart 308
Vraag
What is transcription?
Antwoord
Synthesis of RNA using DNA as a template.
Kaart 309
Vraag
What is a point mutation?
Antwoord
A change affecting one nucleotide pair.
Kaart 310
Vraag
What is an operon?
Antwoord
A group of prokaryotic genes controlled together and transcribed from one promoter.
Kaart 311
Vraag
Why can muscle and nerve cells differ despite having the same genome?
Antwoord
They express different sets and amounts of genes.
Kaart 312
Vraag
What must a virus use from its host?
Antwoord
Host resources and at least some host-cell machinery to copy or express its genome and produce new particles.
Kaart 313
Vraag
What does PCR do?
Antwoord
It amplifies a chosen DNA region through repeated cycles of strand separation, primer binding, and extension.
Kaart 314
Vraag
What enzyme performs transcription?
Antwoord
RNA polymerase.
Kaart 315
Vraag
What does helicase do during replication?
Antwoord
It unwinds the double helix and separates the template strands.
Kaart 316
Vraag
How does a repressor reduce transcription?
Antwoord
It binds regulatory DNA and blocks or hinders transcription machinery.
Kaart 317
Vraag
What is a silent mutation?
Antwoord
A nucleotide change that does not change the encoded amino acid.
Kaart 318
Vraag
What does a promoter do?
Antwoord
It marks where transcription machinery assembles and helps set the transcription start and direction.
Kaart 319
Vraag
What does topoisomerase do ahead of a replication fork?
Antwoord
It relieves twisting strain caused by DNA unwinding.
Kaart 320
Vraag
How does an inducer affect an inducible operon?
Antwoord
It disables the repressor or otherwise turns transcription on when the pathway's substrate is present.
Kaart 321
Vraag
How do DNA and RNA bases differ?
Antwoord
DNA uses thymine, while RNA uses uracil; both also use adenine, cytosine, and guanine.
Kaart 322
Vraag
Which DNA strand does RNA polymerase read?
Antwoord
The template strand, read 3′→5′ while RNA is built 5′→3′.
Kaart 323
Vraag
Why is an RNA primer needed for DNA replication?
Antwoord
DNA polymerase can extend an existing 3′ end but cannot start a strand from nothing.
Kaart 324
Vraag
How does a corepressor affect a repressible operon?
Antwoord
It activates a repressor, turning off genes when the pathway's end product is abundant.
Kaart 325
Vraag
What is a missense mutation?
Antwoord
A nucleotide change that substitutes one amino acid for another.
Kaart 326
Vraag
How does an mRNA sequence relate to the coding DNA strand?
Antwoord
It matches the coding strand except RNA has uracil in place of thymine.
Kaart 327
Vraag
What does primase do?
Antwoord
It builds short RNA primers.
Kaart 328
Vraag
Why is the lac operon strongly expressed when lactose is present and glucose is scarce?
Antwoord
Lactose relieves repression, while low glucose supports positive activation of transcription.
Kaart 329
Vraag
Why are primers essential in PCR?
Antwoord
They define the target boundaries and provide 3′ ends for DNA polymerase.
Kaart 330
Vraag
What is the primary RNA transcript in a eukaryote?
Antwoord
The initial RNA copy before processing.
Kaart 331
Vraag
In which direction does DNA polymerase synthesize DNA?
Antwoord
5′→3′ by adding nucleotides to a 3′ end.
Kaart 332
Vraag
Why is the trp operon usually off when tryptophan is abundant?
Antwoord
Tryptophan acts as a corepressor, enabling repression of biosynthetic genes.
Kaart 333
Vraag
What holds complementary DNA bases together?
Antwoord
Hydrogen bonds: adenine pairs with thymine, and cytosine pairs with guanine.
Kaart 334
Vraag
What happens during RNA splicing?
Antwoord
Introns are removed and exons are joined.
Kaart 335
Vraag
Why is the leading strand synthesized continuously?
Antwoord
Its template orientation lets polymerase follow the replication fork while synthesizing 5′→3′.
Kaart 336
Vraag
How can histone acetylation affect transcription?
Antwoord
It often loosens chromatin and makes DNA more accessible to transcription machinery.
Kaart 337
Vraag
What is a nonsense mutation?
Antwoord
A nucleotide change that creates a premature stop codon.
Kaart 338
Vraag
What do the 5′ cap and poly-A tail help do?
Antwoord
They protect eukaryotic mRNA and support export and translation.
Kaart 339
Vraag
Why is the lagging strand synthesized in fragments?
Antwoord
Its template orientation forces repeated 5′→3′ synthesis away from the moving fork.
Kaart 340
Vraag
How can DNA methylation near a promoter affect transcription?
Antwoord
It often reduces transcription by limiting access or recruiting repressive proteins.
Kaart 341
Vraag
How does gel electrophoresis separate DNA fragments?
Antwoord
An electric field pulls negatively charged DNA through a matrix; smaller fragments usually travel farther.
Kaart 342
Vraag
How can alternative splicing increase protein diversity?
Antwoord
Different exon combinations from one transcript can produce different mRNAs and polypeptides.
Kaart 343
Vraag
What are Okazaki fragments?
Antwoord
Short DNA segments made on the lagging strand.
Kaart 344
Vraag
What does a transcription factor do?
Antwoord
It binds regulatory DNA and helps increase or decrease transcription of specific genes.
Kaart 345
Vraag
Why are DNA strands antiparallel?
Antwoord
Their sugar–phosphate backbones run in opposite 5′→3′ directions.
Kaart 346
Vraag
What is translation?
Antwoord
Ribosomes use an mRNA codon sequence to build a polypeptide.
Kaart 347
Vraag
What does DNA ligase do?
Antwoord
It seals breaks in the sugar–phosphate backbone, joining DNA fragments.
Kaart 348
Vraag
What is a frameshift mutation?
Antwoord
An insertion or deletion not in multiples of three that shifts downstream codon grouping.
Kaart 349
Vraag
How can an enhancer influence a distant promoter?
Antwoord
DNA looping brings enhancer-bound activators near the transcription machinery.
Kaart 350
Vraag
What does a codon specify?
Antwoord
An amino acid or a translation stop signal.
Kaart 351
Vraag
What do restriction enzymes do?
Antwoord
They cut DNA at particular recognition sequences.
Kaart 352
Vraag
What gives a nucleic-acid strand its 5′ and 3′ ends?
Antwoord
The chemical groups on the sugar: a 5′ phosphate end and a 3′ hydroxyl end.
Kaart 353
Vraag
How does proofreading improve replication accuracy?
Antwoord
DNA polymerases detect and replace many incorrectly paired nucleotides.
Kaart 354
Vraag
What does a tRNA anticodon do?
Antwoord
It base-pairs with an mRNA codon so the attached amino acid is placed correctly.
Kaart 355
Vraag
Why can a promoter mutation affect protein amount?
Antwoord
It can change transcription-factor or RNA-polymerase binding and alter transcription rate.
Kaart 356
Vraag
How can microRNA reduce gene expression?
Antwoord
It base-pairs with target mRNA and promotes degradation or blocks translation.
Kaart 357
Vraag
What maintains a differentiated cell's identity?
Antwoord
Stable regulatory networks and chromatin states keep characteristic genes active or silent.
Kaart 358
Vraag
What are the ribosome's broad roles?
Antwoord
It positions mRNA and tRNAs and catalyzes peptide-bond formation.
Kaart 359
Vraag
How can an RNA virus generate genetic variation quickly?
Antwoord
Many viral RNA polymerases lack strong proofreading, so replication introduces mutations frequently.
Kaart 360
Vraag
What can bacterial transformation demonstrate?
Antwoord
Cells can take up external DNA and express a selectable or observable trait.
Kaart 361
Vraag
Why is RNA usually more structurally varied than double-stranded DNA?
Antwoord
A single RNA strand can fold back on itself through internal base pairing.
Kaart 362
Vraag
What usually marks translation initiation?
Antwoord
A start codon positioned with an initiator tRNA and ribosomal subunits.
Kaart 363
Vraag
What problem do telomeres help solve?
Antwoord
They protect chromosome ends from losing essential genes during repeated linear-DNA replication.
Kaart 364
Vraag
Why can an intron splice-site mutation affect protein sequence?
Antwoord
Incorrect splicing can remove exon sequence or retain intron sequence in the mature mRNA.
Kaart 365
Vraag
How can protein degradation regulate a pathway quickly?
Antwoord
Destroying a key protein lowers its activity without waiting for transcription to change.
Kaart 366
Vraag
What happens at a stop codon?
Antwoord
A release factor ends translation and frees the polypeptide.
Kaart 367
Vraag
How can a signal change cell specialization?
Antwoord
It can activate transcription factors that launch a new gene-expression program.
Kaart 368
Vraag
What is a retrovirus's information flow?
Antwoord
Viral RNA is reverse-transcribed into DNA, which can integrate into the host genome.
Kaart 369
Vraag
What does DNA sequencing reveal directly?
Antwoord
The order of nucleotides in the analyzed DNA; biological effects require further interpretation.
Kaart 370
Vraag
Why is the genetic code called redundant?
Antwoord
More than one codon can specify the same amino acid.
Kaart 371
Vraag
Where does nucleotide sequence store information?
Antwoord
The order of bases encodes information that can be copied, transcribed, or translated.
Kaart 372
Vraag
Why is replication called bidirectional?
Antwoord
Two forks usually move away from each origin in opposite directions.
Kaart 373
Vraag
Why doesn't every DNA mutation change phenotype?
Antwoord
It may occur outside a functional sequence, be silent, have a mild effect, or be masked by another allele or environment.
Kaart 374
Vraag
How does a free ribosome's product usually differ from a rough-ER ribosome's product?
Antwoord
Free ribosomes often make cytosolic proteins; ER-bound ribosomes make many secreted, membrane, and endomembrane proteins.
Kaart 375
Vraag
Why can one signal coordinate many genes?
Antwoord
A shared transcription regulator or signaling pathway can control multiple target promoters.
Kaart 376
Vraag
Why does cell specialization depend on selective gene expression rather than gene loss?
Antwoord
Most specialized cells retain the genome but use only the genes needed for their role.
Kaart 377
Vraag
Why are viruses not described as independently living cells?
Antwoord
They lack cellular metabolism and cannot reproduce without a host cell.
Kaart 378
Vraag
A coding DNA triplet is 5′-ATG-3′. What is the matching mRNA codon?
Antwoord
5′-AUG-3′.
Kaart 379
Vraag
A PCR band is absent. Why isn't gene absence the only explanation?
Antwoord
Poor DNA quality, wrong primers, inhibitors, or failed reaction conditions can also prevent amplification.
Kaart 380
Vraag
Why can protein function require steps after translation?
Antwoord
The polypeptide may need folding, cleavage, chemical modification, or assembly with other subunits.
Kaart 381
Vraag
How do fossils support evolution?
Antwoord
They document organisms and transitions through time, including appearance, change, and extinction.
Kaart 382
Vraag
What conditions are required for natural selection?
Antwoord
Individuals vary, some variation is heritable, and variants differ in survival or reproductive success in that environment.
Kaart 383
Vraag
What is artificial selection?
Antwoord
Humans choose which organisms reproduce based on desired heritable traits.
Kaart 384
Vraag
What does an allele frequency measure?
Antwoord
The fraction of all copies of a gene in a population represented by one allele.
Kaart 385
Vraag
What does a node on a phylogenetic tree represent?
Antwoord
A common ancestor where descendant lineages diverge.
Kaart 386
Vraag
What is biological speciation?
Antwoord
Evolution of reproductive isolation between populations, producing independently evolving lineages.
Kaart 387
Vraag
What is extinction?
Antwoord
Permanent loss of a species when no living members remain.
Kaart 388
Vraag
A pesticide-treated population becomes mostly resistant. What evidence distinguishes selection from acclimation?
Antwoord
Resistance should be heritable and increase across generations through differential reproduction, not just appear temporarily in exposed individuals.
Kaart 389
Vraag
What changes during evolution by natural selection?
Antwoord
Allele frequencies in a population across generations.
Kaart 390
Vraag
For two alleles under Hardy–Weinberg notation, what does p + q equal?
Antwoord
1.
Kaart 391
Vraag
What is a clade?
Antwoord
An ancestor and all of its descendants.
Kaart 392
Vraag
What does homologous anatomy suggest?
Antwoord
Similar underlying structures with different functions can indicate inheritance from a common ancestor.
Kaart 393
Vraag
Do individual organisms evolve by natural selection?
Antwoord
No. Individuals are selected; populations evolve as inherited variants change in frequency.
Kaart 394
Vraag
Under Hardy–Weinberg equilibrium, what does p² represent?
Antwoord
Expected frequency of one homozygous genotype.
Kaart 395
Vraag
What is a shared derived character?
Antwoord
A trait that evolved in a common ancestor and helps identify one of its descendant clades.
Kaart 396
Vraag
What is mutation's evolutionary role?
Antwoord
It creates new alleles, the ultimate source of new genetic variation.
Kaart 397
Vraag
What is biological fitness?
Antwoord
Relative contribution of viable, reproducing offspring to the next generation in a particular environment.
Kaart 398
Vraag
Under Hardy–Weinberg equilibrium, what does 2pq represent?
Antwoord
Expected frequency of heterozygotes.
Kaart 399
Vraag
Which two tips on a tree are most closely related?
Antwoord
Those sharing the most recent common ancestor, regardless of how close their names appear on the page.
Kaart 400
Vraag
What is a vestigial structure?
Antwoord
A reduced feature inherited from ancestors that has lost much or all of its earlier function.
Kaart 401
Vraag
What is an adaptation?
Antwoord
A heritable trait that became common because it improved fitness in past environments.
Kaart 402
Vraag
Under Hardy–Weinberg equilibrium, what does q² represent?
Antwoord
Expected frequency of the other homozygous genotype.
Kaart 403
Vraag
How does recombination affect evolution?
Antwoord
It reshuffles existing alleles into new combinations but does not itself create new alleles.
Kaart 404
Vraag
Does rotating branches around a node change relationships?
Antwoord
No. The branching pattern stays the same.
Kaart 405
Vraag
Why isn't an adaptation always beneficial in every setting?
Antwoord
Fitness effects depend on the environment and can involve tradeoffs.
Kaart 406
Vraag
What are the Hardy–Weinberg assumptions?
Antwoord
A very large population, random mating, no mutation, no migration, and no natural selection at the locus.
Kaart 407
Vraag
How can embryological similarities support common ancestry?
Antwoord
Shared developmental patterns can reflect inherited developmental genes and pathways.
Kaart 408
Vraag
What is gene flow?
Antwoord
Movement of alleles between populations through migration and reproduction.
Kaart 409
Vraag
Does natural selection create needed mutations?
Antwoord
No. Mutations arise without regard to need; selection changes the frequencies of their inherited effects.
Kaart 410
Vraag
Why is Hardy–Weinberg equilibrium useful?
Antwoord
It provides a null model for detecting or reasoning about evolutionary change.
Kaart 411
Vraag
Does left-to-right tip order show evolutionary progress?
Antwoord
No. Tip order is a drawing choice, not a ranking from primitive to advanced.
Kaart 412
Vraag
What is allopatric speciation?
Antwoord
Geographic separation reduces gene flow, allowing populations to diverge.
Kaart 413
Vraag
What is directional selection?
Antwoord
Selection favors one end of a phenotypic range, shifting the population mean.
Kaart 414
Vraag
If q² = 0.09, what is q?
Antwoord
0.30.
Kaart 415
Vraag
Why is DNA sequence similarity evidence for relatedness?
Antwoord
Related lineages inherit sequences from common ancestors, with differences accumulating over time.
Kaart 416
Vraag
How does gene flow often affect differences between populations?
Antwoord
It tends to make allele frequencies more similar.
Kaart 417
Vraag
What is stabilizing selection?
Antwoord
Selection favors intermediate phenotypes and removes extremes.
Kaart 418
Vraag
If q = 0.30, what is p?
Antwoord
0.70.
Kaart 419
Vraag
What can branch length mean?
Antwoord
Only what the figure defines—sometimes time or amount of change, and sometimes nothing quantitative.
Kaart 420
Vraag
What is sympatric speciation?
Antwoord
Reproductive isolation evolves without geographic separation, for example through polyploidy or strong niche and mating differences.
Kaart 421
Vraag
What is disruptive selection?
Antwoord
Selection favors both extremes over intermediate phenotypes.
Kaart 422
Vraag
If p = 0.70 and q = 0.30, what is 2pq?
Antwoord
0.42.
Kaart 423
Vraag
Why include an untreated population in a selection experiment?
Antwoord
It shows how allele or trait frequencies change without the selective treatment.
Kaart 424
Vraag
Why is the nearly universal genetic code evidence of common ancestry?
Antwoord
A deeply conserved information system is most simply explained by inheritance from early shared ancestors.
Kaart 425
Vraag
What is balancing selection?
Antwoord
Natural selection that maintains two or more alleles in a population, such as through heterozygote advantage or selection that varies across environments.
Kaart 426
Vraag
What is genetic drift?
Antwoord
Random change in allele frequencies caused by chance sampling across generations.
Kaart 427
Vraag
If 16% of a Hardy–Weinberg population shows a recessive phenotype, what is q?
Antwoord
0.40, because q is the square root of 0.16.
Kaart 428
Vraag
Why use an outgroup in tree analysis?
Antwoord
It helps infer which character states are ancestral versus derived in the focal group.
Kaart 429
Vraag
What is a prezygotic barrier?
Antwoord
A barrier that prevents mating or fertilization.
Kaart 430
Vraag
Allele A rises from 0.20 to 0.45. Describe the evolutionary result.
Antwoord
The population evolved at that locus because allele frequency changed.
Kaart 431
Vraag
How does biogeography support evolution?
Antwoord
Species distributions often match isolation history, dispersal, and descent from nearby ancestors.
Kaart 432
Vraag
What is sexual selection?
Antwoord
Differences in mating success drive changes in traits that affect mate attraction or competition.
Kaart 433
Vraag
When is genetic drift strongest?
Antwoord
In small populations.
Kaart 434
Vraag
Why can a rare recessive allele persist?
Antwoord
Selection cannot remove copies hidden in heterozygotes as efficiently as copies expressed in homozygotes.
Kaart 435
Vraag
How can molecular data revise a phylogenetic tree?
Antwoord
Sequence comparisons can reveal relationships not obvious from morphology or distinguish convergence from homology.
Kaart 436
Vraag
What is a postzygotic barrier?
Antwoord
A barrier that reduces hybrid survival, fertility, or later-generation success after fertilization.
Kaart 437
Vraag
How can rapid environmental change increase extinction risk?
Antwoord
Populations may lack enough suitable variation or time to adapt or move.
Kaart 438
Vraag
A small island population loses alleles after a storm. Which mechanism is most direct?
Antwoord
Genetic drift through a bottleneck.
Kaart 439
Vraag
What is convergent evolution?
Antwoord
Unrelated lineages independently evolve similar traits under similar selective pressures.
Kaart 440
Vraag
Why can antibiotic resistance spread rapidly?
Antwoord
Treatment strongly favors resistant variants already present or newly introduced, which leave more descendants.
Kaart 441
Vraag
What is a bottleneck effect?
Antwoord
A sharp population reduction leaves a random, often less diverse sample of the original gene pool.
Kaart 442
Vraag
How do genotype counts yield allele frequency?
Antwoord
Count two copies from each homozygote and one from each heterozygote, then divide by twice the number of diploid individuals.
Kaart 443
Vraag
What is maximum parsimony in tree building?
Antwoord
Preferring the tree that requires the fewest evolutionary changes under the model.
Kaart 444
Vraag
How can different breeding times isolate populations?
Antwoord
Temporal isolation prevents individuals from mating even when they share a location.
Kaart 445
Vraag
Why can mass extinctions reshape evolution?
Antwoord
They remove many lineages and open ecological opportunities for survivors.
Kaart 446
Vraag
Two similar traits evolved on distant tree branches. What explanation should be evaluated?
Antwoord
Convergent evolution under similar selection, alongside the possibility of an incorrect tree or unrecognized homology.
Kaart 447
Vraag
Why are analogous structures weak evidence of close ancestry?
Antwoord
Their similar function may have evolved independently rather than from the same ancestral structure.
Kaart 448
Vraag
Why doesn't natural selection produce perfection?
Antwoord
It works with existing variation under tradeoffs, historical constraints, chance, and changing environments.
Kaart 449
Vraag
What is a founder effect?
Antwoord
A new population starts from a small, nonrepresentative sample of a source population.
Kaart 450
Vraag
Observed genotypes differ from Hardy–Weinberg expectations. What is supported?
Antwoord
At least one model assumption may not hold, or sampling error may matter; the deviation alone does not identify the cause.
Kaart 451
Vraag
Why is a phylogenetic tree a hypothesis?
Antwoord
It is an evidence-based reconstruction that can change when new data or methods appear.
Kaart 452
Vraag
How can behavioral differences cause isolation?
Antwoord
Different courtship signals reduce mating between populations.
Kaart 453
Vraag
What evidence can test origin-of-life hypotheses?
Antwoord
Chemistry experiments, geological records, molecular comparisons, and plausible self-replicating or membrane-forming systems.
Kaart 454
Vraag
How should fitness be compared in an experiment?
Antwoord
Measure relative reproductive contribution, such as viable offspring, under the same environmental conditions.
Kaart 455
Vraag
What does the fossil record not provide?
Antwoord
A complete sample of every organism or every transitional population.
Kaart 456
Vraag
How can a neutral trait change in frequency?
Antwoord
Genetic drift can shift it by chance, especially in small populations.
Kaart 457
Vraag
How can drift reduce adaptive potential?
Antwoord
It can remove alleles and lower genetic diversity needed under future environmental change.
Kaart 458
Vraag
Why does a large population support Hardy–Weinberg stability?
Antwoord
Chance sampling has less effect on allele frequencies, reducing drift.
Kaart 459
Vraag
If A and B share a more recent node with each other than either shares with C, what does that mean?
Antwoord
A and B are sister taxa and share a more recent common ancestor with each other than with C.
Kaart 460
Vraag
What is adaptive radiation?
Antwoord
Rapid diversification of one ancestral lineage into species using different ecological roles.
Kaart 461
Vraag
What can experiments producing organic molecules from simple chemicals show?
Antwoord
That some building blocks can form under modeled conditions; they do not recreate or prove the exact origin of life.
Kaart 462
Vraag
A correlation links beak size with survival. Why isn't causation settled?
Antwoord
Other traits or habitats may covary with beak size; controlled or multivariable evidence is needed.
Kaart 463
Vraag
Why does agreement among fossils, anatomy, and molecules strengthen an evolutionary claim?
Antwoord
Independent evidence types pointing to the same history make alternative explanations less plausible.
Kaart 464
Vraag
A drought favors deeper beaks. What must be measured to show selection?
Antwoord
Heritable beak variation and differences in survival or reproduction linked to beak depth.
Kaart 465
Vraag
Why can artificial selection produce unintended traits?
Antwoord
Selected genes may be linked to other alleles, and inbreeding can expose harmful recessive alleles.
Kaart 466
Vraag
What data are needed to test Hardy–Weinberg genotype expectations?
Antwoord
Population genotype counts or reliable genotype frequencies for the locus.
Kaart 467
Vraag
Why doesn't one living species count as the ancestor of another on a typical tree?
Antwoord
Living tips represent lineages that have both evolved since their shared ancestral lineage.
Kaart 468
Vraag
Why can reduced gene flow accelerate divergence?
Antwoord
Populations retain separate mutations, drift independently, and respond to different selective pressures.
Kaart 469
Vraag
Why are ribozymes relevant to early-life hypotheses?
Antwoord
RNA can both store information and catalyze reactions, offering a possible bridge before modern DNA–protein systems.
Kaart 470
Vraag
What makes an evolutionary argument strong?
Antwoord
A clear claim, relevant population-level evidence, and reasoning that connects inheritance and differential reproduction to the observed change.
Kaart 471
Vraag
How can a directional response help an organism?
Antwoord
Moving toward resources or away from hazards can improve survival and reproduction.
Kaart 472
Vraag
What is a trophic level?
Antwoord
A feeding position in the flow of energy through an ecosystem.
Kaart 473
Vraag
What processes move carbon into and out of biological molecules?
Antwoord
Photosynthesis fixes carbon; respiration, decomposition, and combustion release carbon dioxide.
Kaart 474
Vraag
What does exponential population growth assume?
Antwoord
Resources are effectively unlimited and the per-capita growth rate stays constant.
Kaart 475
Vraag
What is a density-dependent limiting factor?
Antwoord
Its effect strengthens as population density rises, such as competition, disease, or predation.
Kaart 476
Vraag
What is a keystone species?
Antwoord
A species whose ecological effect is disproportionately large relative to its abundance.
Kaart 477
Vraag
What are three levels of biodiversity?
Antwoord
Genetic diversity, species diversity, and ecosystem diversity.
Kaart 478
Vraag
What is the independent variable in a fertilizer–algae experiment?
Antwoord
The fertilizer amount or nutrient concentration deliberately changed.
Kaart 479
Vraag
What shape represents exponential growth over time?
Antwoord
A J-shaped curve.
Kaart 480
Vraag
What do primary producers do?
Antwoord
They capture external energy and build organic molecules from inorganic carbon.
Kaart 481
Vraag
What is a density-independent limiting factor?
Antwoord
Its effect is not primarily set by population density, such as a severe freeze or wildfire.
Kaart 482
Vraag
Why is nitrogen fixation necessary?
Antwoord
Most organisms cannot use atmospheric nitrogen gas directly, so it must be converted to biologically available compounds.
Kaart 483
Vraag
What does logistic growth add to the exponential model?
Antwoord
Growth slows as population size approaches carrying capacity.
Kaart 484
Vraag
What is gross primary productivity?
Antwoord
The total rate at which producers capture energy in organic matter.
Kaart 485
Vraag
What is competition?
Antwoord
An interaction in which organisms using the same limited resource reduce one another's access or fitness.
Kaart 486
Vraag
What is ecological succession?
Antwoord
Change in community composition after new habitat forms or a disturbance alters an existing community.
Kaart 487
Vraag
What shape represents ideal logistic growth?
Antwoord
An S-shaped curve.
Kaart 488
Vraag
What is net primary productivity?
Antwoord
Gross primary productivity minus producers' respiratory energy use.
Kaart 489
Vraag
Why does genetic diversity matter for conservation?
Antwoord
It increases the range of inherited responses available under disease or environmental change.
Kaart 490
Vraag
What organisms perform much biological nitrogen fixation?
Antwoord
Certain prokaryotes, including free-living and symbiotic bacteria.
Kaart 491
Vraag
What is carrying capacity?
Antwoord
The population size an environment can sustain over time under current conditions.
Kaart 492
Vraag
Why is net primary productivity important to consumers?
Antwoord
It is the producer biomass and energy available for growth and the next trophic levels.
Kaart 493
Vraag
What is competitive exclusion?
Antwoord
Species with identical limiting-resource niches cannot coexist indefinitely under stable conditions.
Kaart 494
Vraag
How do primary and secondary succession differ?
Antwoord
Primary succession begins without developed soil; secondary succession begins where soil remains.
Kaart 495
Vraag
Why can carrying capacity change?
Antwoord
Resources, habitat, climate, competitors, disease, and disturbance can change.
Kaart 496
Vraag
Why does available energy decline up a food chain?
Antwoord
Organisms use much energy for metabolism and lose it as heat and waste rather than storing it as biomass.
Kaart 497
Vraag
What is an ecosystem service?
Antwoord
A benefit people receive from ecosystems, such as pollination, water purification, soil formation, or climate regulation.
Kaart 498
Vraag
What does nitrification do?
Antwoord
Microbes oxidize ammonium to nitrite and then nitrate.
Kaart 499
Vraag
What does per-capita growth rate measure?
Antwoord
Population change per individual per unit time.
Kaart 500
Vraag
What is ecological efficiency?
Antwoord
The percentage of energy or production transferred from one trophic level to the next.
Kaart 501
Vraag
What is resource partitioning?
Antwoord
Competing species use different resources, places, or times, reducing direct overlap.
Kaart 502
Vraag
What is resilience in an ecosystem?
Antwoord
The ability to recover structure or function after disturbance.
Kaart 503
Vraag
How is population growth estimated from births, deaths, immigration, and emigration?
Antwoord
Births + immigration − deaths − emigration.
Kaart 504
Vraag
If producers store 10,000 kJ and primary consumers receive 10%, how much do they receive?
Antwoord
1,000 kJ.
Kaart 505
Vraag
How does habitat fragmentation affect populations?
Antwoord
It shrinks and isolates habitat, reducing movement and gene flow while increasing edge effects.
Kaart 506
Vraag
Why sample several sites within each habitat?
Antwoord
Replication captures spatial variation and reduces the chance that one unusual site drives the result.
Kaart 507
Vraag
A population grows from 200 to 230 in one year. What is its percent growth?
Antwoord
15%, because the increase of 30 divided by 200 is 0.15.
Kaart 508
Vraag
What is a circadian rhythm?
Antwoord
An internal roughly 24-hour cycle that environmental cues can reset.
Kaart 509
Vraag
Why are food webs more realistic than simple food chains?
Antwoord
Most species eat or are eaten by multiple species, creating connected pathways.
Kaart 510
Vraag
What does denitrification do?
Antwoord
Microbes convert nitrate to nitrogen gases, returning nitrogen to the atmosphere.
Kaart 511
Vraag
What characterizes an r-selected life-history strategy?
Antwoord
Many offspring, early reproduction, and relatively low investment per offspring in variable environments.
Kaart 512
Vraag
What is mutualism?
Antwoord
An interaction that benefits both species.
Kaart 513
Vraag
What is resistance in an ecosystem?
Antwoord
The ability to remain relatively unchanged during disturbance.
Kaart 514
Vraag
How can climate change shift species ranges?
Antwoord
Organisms track suitable temperature, moisture, seasons, or interacting species when movement is possible.
Kaart 515
Vraag
What characterizes a K-selected life-history strategy?
Antwoord
Fewer offspring, later reproduction, and higher investment per offspring near carrying capacity.
Kaart 516
Vraag
A population curve levels near 800. What does the model suggest?
Antwoord
About 800 is the carrying capacity under those measured conditions, not a permanent universal value.
Kaart 517
Vraag
How can seasonal cues affect reproduction?
Antwoord
Changes such as day length can trigger hormonal and behavioral shifts timed to favorable conditions.
Kaart 518
Vraag
What role do decomposers play?
Antwoord
They break down dead material and waste, returning nutrients to forms other organisms can use.
Kaart 519
Vraag
Why can phosphorus limit ecosystems?
Antwoord
It is essential but often released slowly from rocks and lacks a large atmospheric gas phase.
Kaart 520
Vraag
What does a Type I survivorship curve show?
Antwoord
High survival through early and middle life, followed by a steep decline at older ages.
Kaart 521
Vraag
What is commensalism?
Antwoord
One species benefits while the other has no clear benefit or harm.
Kaart 522
Vraag
Why can diversity improve ecosystem stability?
Antwoord
Multiple species or response types can keep functions going when one component declines.
Kaart 523
Vraag
Why can overharvesting destabilize a population?
Antwoord
Removal faster than replacement lowers abundance and can alter age structure or genetic diversity.
Kaart 524
Vraag
Predator and prey peaks alternate over time. What can the graph establish?
Antwoord
Their abundances covary with a lag; the graph alone cannot prove the predator caused every prey change.
Kaart 525
Vraag
What is acclimation?
Antwoord
A reversible phenotypic adjustment by an individual to an environmental change.
Kaart 526
Vraag
Does energy cycle through an ecosystem?
Antwoord
No. Energy flows through and is ultimately dissipated as heat; matter cycles.
Kaart 527
Vraag
How does the water cycle connect ecosystems?
Antwoord
Evaporation, transpiration, condensation, precipitation, runoff, and infiltration move water and dissolved materials.
Kaart 528
Vraag
What does a Type II survivorship curve show?
Antwoord
A roughly constant mortality risk across ages.
Kaart 529
Vraag
What is parasitism?
Antwoord
A parasite benefits while reducing its host's fitness.
Kaart 530
Vraag
What is an invasive species?
Antwoord
A nonnative species that spreads and causes ecological, economic, or human-health harm.
Kaart 531
Vraag
How can a wildlife corridor help fragmented populations?
Antwoord
It supports movement, recolonization, and gene flow between habitat patches.
Kaart 532
Vraag
How should biodiversity be compared when sample effort differs?
Antwoord
Standardize sampling effort or use a method that accounts for unequal effort before comparing.
Kaart 533
Vraag
How does acclimation differ from adaptation?
Antwoord
Acclimation occurs within an individual; adaptation is an inherited population change across generations.
Kaart 534
Vraag
How can removal of a top predator affect lower trophic levels?
Antwoord
It can trigger a trophic cascade by changing prey abundance and the organisms prey consume.
Kaart 535
Vraag
Why can extra fertilizer cause low oxygen in water?
Antwoord
Nutrient enrichment drives algal growth; decomposition then consumes dissolved oxygen.
Kaart 536
Vraag
What does a Type III survivorship curve show?
Antwoord
High early mortality with much better survival among those reaching later stages.
Kaart 537
Vraag
How can predation maintain diversity?
Antwoord
A predator can prevent one strong competitor from dominating the community.
Kaart 538
Vraag
How can disturbance increase or decrease diversity?
Antwoord
Its effect depends on frequency and intensity; it may create habitat variety or eliminate sensitive species.
Kaart 539
Vraag
Why protect multiple habitats rather than one small reserve?
Antwoord
Different habitats, disturbances, and climate trajectories preserve more species and ecological options.
Kaart 540
Vraag
A restoration site gains species but not nutrient cycling. How should success be evaluated?
Antwoord
Use both composition and ecosystem-function measures; one metric alone gives an incomplete result.
540 kaarten
AP Biology Flashcards: Complete 8-Unit Course Review
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