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