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