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