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