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.
دربارهٔ این دسته
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
کارتهای این دسته
کارت ۱
پرسش
Why is a water molecule polar?
پاسخ
Oxygen pulls shared electrons more strongly than hydrogen, giving oxygen a partial negative charge and the hydrogens partial positive charges.
کارت ۲
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Which elements make up most biological molecules?
پاسخ
Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur—often shortened to CHNOPS.
کارت ۳
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What is the relationship between a monomer and a polymer?
پاسخ
Monomers are small building blocks; polymers are chains or networks made from repeated monomers.
کارت ۴
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What is a monosaccharide's main role in cells?
پاسخ
It can provide quick energy and serve as a building block for larger carbohydrates.
کارت ۵
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Why do lipids mix poorly with water?
پاسخ
Most of their bonds are nonpolar, so water cannot form favorable interactions with them.
کارت ۶
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What three parts make up a nucleotide?
پاسخ
A five-carbon sugar, a phosphate group, and a nitrogenous base.
کارت ۷
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What parts of an amino acid vary and stay constant?
پاسخ
The amino group, carboxyl group, hydrogen, and central carbon are shared; the side chain, or R group, varies.
کارت ۸
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What does pH measure?
پاسخ
The negative logarithm of hydrogen-ion concentration; lower pH means more hydrogen ions.
کارت ۹
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What is a hydrogen bond in liquid water?
پاسخ
A weak attraction between a partially positive hydrogen on one water molecule and a partially negative oxygen on another.
کارت ۱۰
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How does an unsaturated fatty acid differ from a saturated one?
پاسخ
An unsaturated fatty acid has at least one carbon–carbon double bond; a saturated fatty acid has none.
کارت ۱۱
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What bond links amino acids in a polypeptide?
پاسخ
A peptide bond.
کارت ۱۲
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What does dehydration synthesis do?
پاسخ
It joins subunits with a covalent bond while removing the elements of water.
کارت ۱۳
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How does cohesion help water move through a plant?
پاسخ
Hydrogen bonds keep water molecules linked, helping a continuous column rise through xylem.
کارت ۱۴
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How do plants and animals differ in short-term glucose storage?
پاسخ
Plants store glucose mainly as starch; animals store it mainly as glycogen.
کارت ۱۵
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What determines a protein's primary structure?
پاسخ
Its amino-acid sequence.
کارت ۱۶
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How does a cis double bond affect a fatty-acid tail?
پاسخ
It introduces a bend that prevents neighboring tails from packing tightly.
کارت ۱۷
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How does adhesion support water transport in narrow tubes?
پاسخ
Water sticks to polar surfaces, helping it resist gravity along cell walls.
کارت ۱۸
پرسش
Which base pairing distinguishes RNA from DNA?
پاسخ
RNA uses uracil, so adenine pairs with uracil instead of thymine.
کارت ۱۹
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What stabilizes common protein secondary structures?
پاسخ
Hydrogen bonds between atoms in the polypeptide backbone.
کارت ۲۰
پرسش
Why can carbon form so many biological structures?
پاسخ
It has four valence electrons and can form four stable covalent bonds, including chains, branches, and rings.
کارت ۲۱
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Why can some insects stand on water?
پاسخ
Cohesion among surface water molecules creates high surface tension.
کارت ۲۲
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What does hydrolysis do to a biological polymer?
پاسخ
It adds the elements of water to break a covalent bond between subunits.
کارت ۲۳
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What carbohydrate strengthens plant cell walls?
پاسخ
Cellulose.
کارت ۲۴
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Why are fats useful for long-term energy storage?
پاسخ
Their many C–H bonds store substantial chemical energy, and hydrophobic storage adds little water mass.
کارت ۲۵
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How does water buffer rapid temperature change?
پاسخ
Breaking and forming many hydrogen bonds absorbs or releases substantial heat, giving water a high specific heat.
کارت ۲۶
پرسش
What does antiparallel mean for a DNA double helix?
پاسخ
Its two strands run in opposite directions: one 5′→3′ and the other 3′→5′.
کارت ۲۷
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What mainly drives a protein's tertiary structure?
پاسخ
Interactions among side chains, including hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.
کارت ۲۸
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What is a trace element?
پاسخ
An element an organism needs in very small amounts, such as iron in many electron-transfer proteins.
کارت ۲۹
پرسش
Why does sweating cool an organism?
پاسخ
The fastest water molecules escape as vapor, carrying heat away from the surface.
کارت ۳۰
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A cell builds a polysaccharide from sugars. Is water consumed or released?
پاسخ
Released. Forming each linkage by dehydration removes water.
کارت ۳۱
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Why can branching help a storage polysaccharide release glucose quickly?
پاسخ
More branch ends give enzymes more sites to work at once.
کارت ۳۲
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What makes a phospholipid amphipathic?
پاسخ
It has a polar, hydrophilic head and nonpolar, hydrophobic tails.
کارت ۳۳
پرسش
Where is biological information encoded in a nucleic acid?
پاسخ
In the linear sequence of nucleotide bases.
کارت ۳۴
پرسش
What is quaternary protein structure?
پاسخ
The arrangement of two or more polypeptide subunits into one functional protein.
کارت ۳۵
پرسش
Why does ice float on liquid water?
پاسخ
Stable hydrogen bonds hold ice molecules in an open lattice, making ice less dense than liquid water.
کارت ۳۶
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How does electronegativity affect a covalent bond?
پاسخ
A difference in attraction for electrons makes electron sharing unequal and can create a polar bond.
کارت ۳۷
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A digestive reaction adds water while splitting a macromolecule. What reaction is this?
پاسخ
Hydrolysis.
کارت ۳۸
پرسش
What links monosaccharides in a polysaccharide?
پاسخ
Glycosidic covalent bonds.
کارت ۳۹
پرسش
Why do phospholipids form bilayers in water?
پاسخ
Hydrophilic heads face water while hydrophobic tails cluster away from it.
کارت ۴۰
پرسش
To which end are nucleotides added during nucleic-acid synthesis?
پاسخ
The 3′ end of the growing strand.
کارت ۴۱
پرسش
Why can one amino-acid substitution change protein function?
پاسخ
It can alter side-chain interactions, folding, stability, or an active or binding site.
کارت ۴۲
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How does a buffer resist a pH change?
پاسخ
It can accept added hydrogen ions or donate them when hydrogen-ion concentration falls.
کارت ۴۳
پرسش
Why is water a useful solvent for cells?
پاسخ
Its partial charges surround ions and other polar molecules, separating and dispersing them.
کارت ۴۴
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Why do functional groups matter in organic molecules?
پاسخ
They give carbon skeletons predictable chemical properties, such as polarity, acidity, or reactivity.
کارت ۴۵
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Why can two polymers built from similar monomers have different functions?
پاسخ
Their monomer sequence, branching, length, and three-dimensional shape can differ.
کارت ۴۶
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A seedling consumes stored starch. What happens to the starch?
پاسخ
Hydrolysis breaks it into smaller sugars that can enter energy pathways.
کارت ۴۷
پرسش
What are two biological roles of steroids?
پاسخ
Some act as signaling molecules, and cholesterol helps stabilize animal cell membranes.
کارت ۴۸
پرسش
What bond forms the backbone of a nucleic-acid strand?
پاسخ
Covalent phosphodiester bonds link the sugar of one nucleotide to the phosphate of the next.
کارت ۴۹
پرسش
What does denaturation do to a protein?
پاسخ
It disrupts the protein's three-dimensional shape and often its function without usually breaking the primary peptide chain.
کارت ۵۰
پرسش
An enzyme works best near pH 7 but slows at pH 3. What is a likely explanation?
پاسخ
Extra hydrogen ions changed charges and interactions that maintain the enzyme's active shape.
کارت ۵۱
پرسش
What structure encloses every cell?
پاسخ
A plasma membrane.
کارت ۵۲
پرسش
What is the nucleus's main function?
پاسخ
It houses most eukaryotic DNA and is a major site of DNA replication and transcription.
کارت ۵۳
پرسش
Why does surface-area-to-volume ratio fall as a cell grows?
پاسخ
Volume increases with the cube of length, while surface area increases with the square.
کارت ۵۴
پرسش
What does the fluid mosaic model describe?
پاسخ
A dynamic phospholipid bilayer containing mobile proteins, sterols, and carbohydrates.
کارت ۵۵
پرسش
What drives simple diffusion?
پاسخ
Random molecular motion produces net movement from higher to lower concentration.
کارت ۵۶
پرسش
How does active transport differ from facilitated diffusion?
پاسخ
Active transport moves a substance against its gradient using energy; facilitated diffusion moves it down a gradient.
کارت ۵۷
پرسش
Why does compartmentalization increase cellular efficiency?
پاسخ
It concentrates enzymes and substrates and maintains distinct conditions for different reactions.
کارت ۵۸
پرسش
When should a light microscope be preferred over an electron microscope?
پاسخ
When observing living cells or dynamic processes at lower resolution.
کارت ۵۹
پرسش
What does the nucleolus produce?
پاسخ
Ribosomal RNA and early ribosome subunits.
کارت ۶۰
پرسش
Does passive transport require direct cellular energy?
پاسخ
No. It moves substances down an electrochemical or concentration gradient.
کارت ۶۱
پرسش
What feature separates prokaryotic from eukaryotic cells?
پاسخ
Eukaryotic cells have a membrane-bound nucleus and other membrane-bound organelles; prokaryotic cells do not.
کارت ۶۲
پرسش
Which membrane region blocks most ions and polar molecules?
پاسخ
The hydrophobic interior formed by phospholipid tails.
کارت ۶۳
پرسش
What happens on rough endoplasmic reticulum?
پاسخ
Bound ribosomes make proteins for secretion, membranes, or the endomembrane system.
کارت ۶۴
پرسش
How does facilitated diffusion differ from simple diffusion?
پاسخ
It uses a channel or carrier protein but still moves a substance down its gradient.
کارت ۶۵
پرسش
Where is prokaryotic DNA usually located?
پاسخ
In a nucleoid region rather than inside a membrane-bound nucleus.
کارت ۶۶
پرسش
How does cholesterol affect an animal membrane?
پاسخ
It buffers fluidity, limiting excess movement when warm and preventing tight packing when cool.
کارت ۶۷
پرسش
What does smooth endoplasmic reticulum do?
پاسخ
It synthesizes lipids, detoxifies some compounds, and stores calcium in specialized cells.
کارت ۶۸
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What determines a channel protein's selectivity?
پاسخ
Its pore size, shape, charge, and gating behavior.
کارت ۶۹
پرسش
What does the sodium–potassium pump accomplish?
پاسخ
Using ATP, it exports three sodium ions and imports two potassium ions per cycle.
کارت ۷۰
پرسش
What do ribosomes do in both prokaryotic and eukaryotic cells?
پاسخ
They translate mRNA into polypeptides.
کارت ۷۱
پرسش
What is the Golgi apparatus's role?
پاسخ
It modifies, sorts, and packages proteins and lipids arriving from the endoplasmic reticulum.
کارت ۷۲
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What is osmosis?
پاسخ
Net movement of water across a selectively permeable membrane toward lower free-water concentration.
کارت ۷۳
پرسش
Why does a high surface-area-to-volume ratio help a cell?
پاسخ
It provides more membrane area per unit of cytoplasm for exchange with the environment.
کارت ۷۴
پرسش
How do unsaturated phospholipid tails affect membrane fluidity?
پاسخ
Their bends reduce tight packing, usually increasing fluidity.
کارت ۷۵
پرسش
Trace a secreted protein after translation begins.
پاسخ
Rough ER → transport vesicle → Golgi → secretory vesicle → plasma membrane.
کارت ۷۶
پرسش
What happens to an animal cell in a hypotonic solution?
پاسخ
Water enters; the cell swells and may lyse.
کارت ۷۷
پرسش
What is cotransport?
پاسخ
The downhill movement of one substance powers the uphill transport of another through the same protein.
کارت ۷۸
پرسش
What is the main role of a cell wall?
پاسخ
It provides structural support and helps prevent excessive expansion.
کارت ۷۹
پرسش
What do lysosomes do?
پاسخ
Their hydrolytic enzymes digest macromolecules and recycle damaged cell parts in an acidic compartment.
کارت ۸۰
پرسش
What happens to an animal cell in a hypertonic solution?
پاسخ
Water leaves; the cell shrinks.
کارت ۸۱
پرسش
How do intestinal microvilli improve absorption?
پاسخ
They increase membrane surface area without greatly increasing cell volume.
کارت ۸۲
پرسش
What can an integral membrane protein do?
پاسخ
It can transport substances, receive signals, catalyze reactions, or anchor cell structures.
کارت ۸۳
پرسش
What is a central vacuole's major role in a plant cell?
پاسخ
It stores solutes and water and helps maintain turgor pressure.
کارت ۸۴
پرسش
What happens to a plant cell in a hypotonic solution?
پاسخ
Water enters and turgor pressure rises; the cell wall helps prevent bursting.
کارت ۸۵
پرسش
How can a proton gradient power sucrose uptake in a plant cell?
پاسخ
Protons flow down their gradient through a symporter that carries sucrose uphill.
کارت ۸۶
پرسش
What evidence supports the endosymbiotic origin of mitochondria?
پاسخ
They have double membranes, circular DNA, bacterial-like ribosomes, and divide independently by a similar process.
کارت ۸۷
پرسش
Which overall energy-conversion pathway mainly occurs in mitochondria?
پاسخ
Most stages of aerobic cellular respiration and ATP production.
کارت ۸۸
پرسش
What happens to a plant cell in a hypertonic solution?
پاسخ
Water leaves, turgor falls, and the membrane may pull from the wall during plasmolysis.
کارت ۸۹
پرسش
Why can't a standard light microscope resolve a ribosome clearly?
پاسخ
A ribosome is smaller than the microscope's diffraction-limited resolution.
کارت ۹۰
پرسش
How do bacterial and plant cell walls differ?
پاسخ
Bacterial walls usually contain peptidoglycan; plant walls contain cellulose.
کارت ۹۱
پرسش
Which overall energy-conversion pathway occurs in chloroplasts?
پاسخ
Photosynthesis: converting light energy into chemical energy and fixing carbon.
کارت ۹۲
پرسش
A cubical cell doubles each side length. How do surface area and volume change?
پاسخ
Surface area increases 4-fold; volume increases 8-fold.
کارت ۹۳
پرسش
What is the role of membrane carbohydrates?
پاسخ
They help cells recognize and interact with one another.
کارت ۹۴
پرسش
What is water potential?
پاسخ
A measure predicting water movement; water moves from higher to lower water potential.
کارت ۹۵
پرسش
How do microtubules support a cell?
پاسخ
They resist compression, form tracks for motors, and build structures such as spindles, cilia, and flagella.
کارت ۹۶
پرسش
What is endocytosis?
پاسخ
The plasma membrane folds inward to bring material into the cell in a vesicle.
کارت ۹۷
پرسش
What evidence supports the endosymbiotic origin of chloroplasts?
پاسخ
They share bacterial-like DNA, ribosomes, division, and a double membrane consistent with engulfment.
کارت ۹۸
پرسش
In a membrane-permeability test, what is the independent variable?
پاسخ
The factor deliberately changed, such as temperature or solute identity.
کارت ۹۹
پرسش
How do microfilaments support cell movement?
پاسخ
Actin filaments interact with motor proteins to change cell shape, contract, and move materials.
کارت ۱۰۰
پرسش
What does the cytosol contain?
پاسخ
Water, ions, small molecules, and proteins where many metabolic reactions occur.
کارت ۱۰۱
پرسش
Why can diffusion limit cell size?
پاسخ
As dimensions grow, molecules must travel farther, while exchange area does not keep pace with metabolic volume.
کارت ۱۰۲
پرسش
What does selective permeability mean?
پاسخ
The membrane allows some substances to cross more readily than others.
کارت ۱۰۳
پرسش
What is an intermediate filament's general role?
پاسخ
It provides durable mechanical strength and helps anchor structures.
کارت ۱۰۴
پرسش
How does adding a nonpenetrating solute affect water potential?
پاسخ
It makes solute potential, and usually total water potential, more negative.
کارت ۱۰۵
پرسش
What is exocytosis?
پاسخ
A vesicle fuses with the plasma membrane and releases contents outside the cell.
کارت ۱۰۶
پرسش
Why can lysosomal enzymes digest safely inside a cell?
پاسخ
A membrane isolates the acidic enzymes from most cytosolic components.
کارت ۱۰۷
پرسش
Why include an untreated membrane sample in an experiment?
پاسخ
It provides a control baseline for judging the treatment's effect.
کارت ۱۰۸
پرسش
Why doesn't cell size alone identify whether a cell is prokaryotic?
پاسخ
Sizes overlap; the presence or absence of internal membrane-bound structures is stronger evidence.
کارت ۱۰۹
پرسش
Why are organelle interactions important?
پاسخ
Cell functions often require products to move through several specialized compartments rather than one organelle working alone.
کارت ۱۱۰
پرسش
What graph would show a size constraint clearly?
پاسخ
Plot cell size on the x-axis and surface-area-to-volume ratio on the y-axis; the ratio should decline as size rises.
کارت ۱۱۱
پرسش
Which molecules cross a phospholipid bilayer most easily without proteins?
پاسخ
Small nonpolar molecules, such as oxygen and carbon dioxide.
کارت ۱۱۲
پرسش
Two solutions have equal water potential. What is the net water movement?
پاسخ
None, although water molecules still move both ways.
کارت ۱۱۳
پرسش
Why is ATP loss likely to disrupt ion balance?
پاسخ
ATP-powered pumps stop maintaining gradients, so passive leaks move ions toward equilibrium.
کارت ۱۱۴
پرسش
How does folding an internal membrane help an organelle?
پاسخ
It increases surface area for membrane-bound reactions without a matching increase in volume.
کارت ۱۱۵
پرسش
A dye leaves heated cells faster than unheated cells. What conclusion is supported?
پاسخ
Heating increased membrane permeability under the tested conditions; the data alone do not identify the exact molecular damage.
کارت ۱۱۶
پرسش
What does an enzyme change in a reaction?
پاسخ
It lowers activation energy, increasing reaction rate without changing the reaction's overall free-energy change.
کارت ۱۱۷
پرسش
What makes a reaction exergonic?
پاسخ
It releases free energy and has a negative change in free energy under the stated conditions.
کارت ۱۱۸
پرسش
What are the overall inputs and outputs of photosynthesis?
پاسخ
Carbon dioxide and water use light energy to produce carbohydrate and oxygen.
کارت ۱۱۹
پرسش
What are the overall reactants and products of aerobic cellular respiration?
پاسخ
Organic fuel and oxygen are converted mainly to carbon dioxide, water, and ATP, with heat released.
کارت ۱۲۰
پرسش
How should reaction rate be calculated from product data?
پاسخ
Divide the change in product amount by the elapsed time.
کارت ۱۲۱
پرسش
What makes an enzyme substrate-specific?
پاسخ
The active site's shape and chemical properties favor particular substrates.
کارت ۱۲۲
پرسش
Where do the light reactions occur?
پاسخ
In the thylakoid membranes of chloroplasts.
کارت ۱۲۳
پرسش
Where does glycolysis occur?
پاسخ
In the cytosol.
کارت ۱۲۴
پرسش
What makes a reaction endergonic?
پاسخ
It requires a net input of free energy and has a positive change in free energy.
کارت ۱۲۵
پرسش
What is induced fit?
پاسخ
Substrate binding shifts the enzyme's shape into a form that better supports catalysis.
کارت ۱۲۶
پرسش
Where does the Calvin cycle occur?
پاسخ
In the chloroplast stroma.
کارت ۱۲۷
پرسش
What does glycolysis produce per glucose?
پاسخ
Two pyruvate, a net two ATP, and two NADH.
کارت ۱۲۸
پرسش
How can cells drive an endergonic reaction?
پاسخ
They couple it to a sufficiently exergonic reaction so the combined free-energy change is negative.
کارت ۱۲۹
پرسش
Why isn't an enzyme consumed by the reaction it catalyzes?
پاسخ
It returns to a reusable form after products leave the active site.
کارت ۱۳۰
پرسش
What do photosynthetic pigments do?
پاسخ
They absorb particular wavelengths and transfer excitation energy into the light reactions.
کارت ۱۳۱
پرسش
Does glycolysis require oxygen directly?
پاسخ
No. It can run without oxygen if NAD⁺ is regenerated.
کارت ۱۳۲
پرسش
What does ATP hydrolysis commonly provide?
پاسخ
Usable free energy and a phosphate group that can change a molecule's reactivity or protein shape.
کارت ۱۳۳
پرسش
How does substrate concentration affect rate at low concentrations?
پاسخ
Rate usually rises because more substrate molecules collide with available active sites.
کارت ۱۳۴
پرسش
Why do chlorophyll-containing leaves reflect green light?
پاسخ
Chlorophyll absorbs green wavelengths less strongly than red and blue wavelengths.
کارت ۱۳۵
پرسش
Where does pyruvate oxidation occur in a eukaryotic cell?
پاسخ
In the mitochondrial matrix.
کارت ۱۳۶
پرسش
Why is ATP called an energy-coupling molecule?
پاسخ
Its hydrolysis links energy-releasing processes to cellular work.
کارت ۱۳۷
پرسش
Why does enzyme rate plateau at high substrate concentration?
پاسخ
Most active sites are occupied, so enzyme amount becomes limiting.
کارت ۱۳۸
پرسش
What is photolysis of water?
پاسخ
Light-driven splitting of water that supplies electrons and protons and releases oxygen.
کارت ۱۳۹
پرسش
What happens during pyruvate oxidation?
پاسخ
Each pyruvate becomes acetyl-CoA, releasing carbon dioxide and reducing NAD⁺ to NADH.
کارت ۱۴۰
پرسش
Why measure an initial enzyme rate?
پاسخ
Substrate depletion and product buildup have had less time to distort the rate.
کارت ۱۴۱
پرسش
How can high temperature reduce enzyme activity?
پاسخ
Heat can disrupt interactions that maintain the enzyme's functional shape.
کارت ۱۴۲
پرسش
What is photosystem II's key contribution?
پاسخ
It excites electrons and replaces them by oxidizing water.
کارت ۱۴۳
پرسش
Where does the citric acid cycle occur in eukaryotes?
پاسخ
In the mitochondrial matrix.
کارت ۱۴۴
پرسش
What is oxidation?
پاسخ
Loss of electrons, often accompanied by loss of hydrogen or gain of oxygen.
کارت ۱۴۵
پرسش
Why does each enzyme have an optimal pH range?
پاسخ
pH changes charges on amino-acid side chains and can alter binding or folding.
کارت ۱۴۶
پرسش
What does the photosynthetic electron transport chain build?
پاسخ
A proton gradient across the thylakoid membrane.
کارت ۱۴۷
پرسش
What is the citric acid cycle's main energy role?
پاسخ
It oxidizes acetyl groups and transfers electrons to NADH and FADH₂, making a small amount of ATP.
کارت ۱۴۸
پرسش
In a photosynthesis experiment, why keep leaf area constant?
پاسخ
Leaf area affects light capture and gas exchange, so changing it could confound the tested factor.
کارت ۱۴۹
پرسش
How does a competitive inhibitor reduce enzyme activity?
پاسخ
It competes with substrate for the active site.
کارت ۱۵۰
پرسش
How does chloroplast ATP synthase make ATP?
پاسخ
Protons flow from the thylakoid space to the stroma through ATP synthase, driving phosphorylation of ADP.
کارت ۱۵۱
پرسش
Where is the respiratory electron transport chain located in eukaryotes?
پاسخ
In the inner mitochondrial membrane.
کارت ۱۵۲
پرسش
What is reduction?
پاسخ
Gain of electrons, often accompanied by gain of hydrogen or loss of oxygen.
کارت ۱۵۳
پرسش
How can extra substrate weaken competitive inhibition?
پاسخ
More substrate increases the chance that substrate, rather than inhibitor, occupies the active site.
کارت ۱۵۴
پرسش
What is photosystem I's key contribution?
پاسخ
It re-energizes electrons used to reduce NADP⁺ to NADPH.
کارت ۱۵۵
پرسش
What is oxygen's role in aerobic respiration?
پاسخ
It is the final electron acceptor and combines with electrons and protons to form water.
کارت ۱۵۶
پرسش
A respiration graph gets steeper after temperature rises. What does the slope show?
پاسخ
A higher rate of the measured respiratory change, such as oxygen consumption per unit time.
کارت ۱۵۷
پرسش
How does a noncompetitive inhibitor act?
پاسخ
It binds away from the active site and changes enzyme activity, often by altering shape.
کارت ۱۵۸
پرسش
What products of the light reactions feed the Calvin cycle?
پاسخ
ATP and NADPH.
کارت ۱۵۹
پرسش
How does electron transport create a proton gradient?
پاسخ
Released electron energy pumps protons from the matrix to the intermembrane space.
کارت ۱۶۰
پرسش
What do NADH and FADH₂ carry?
پاسخ
High-energy electrons and associated hydrogen used in energy-transfer pathways.
کارت ۱۶۱
پرسش
What is allosteric regulation?
پاسخ
A regulator binds at one site and changes activity at another site on the protein.
کارت ۱۶۲
پرسش
What does carbon fixation accomplish?
پاسخ
It incorporates inorganic carbon dioxide into an organic molecule.
کارت ۱۶۳
پرسش
What is oxidative phosphorylation?
پاسخ
ATP production powered by electron transport and chemiosmosis.
کارت ۱۶۴
پرسش
Why use multiple biological replicates in a rate experiment?
پاسخ
They reveal natural variation and make the estimated treatment effect more reliable.
کارت ۱۶۵
پرسش
What is fermentation's central purpose?
پاسخ
It regenerates NAD⁺ so glycolysis can continue without an active electron transport chain.
کارت ۱۶۶
پرسش
How does feedback inhibition control a pathway?
پاسخ
A pathway's end product inhibits an earlier enzyme, reducing unnecessary production.
کارت ۱۶۷
پرسش
What enzyme fixes carbon in the Calvin cycle?
پاسخ
Rubisco.
کارت ۱۶۸
پرسش
How does mitochondrial ATP synthase make ATP?
پاسخ
Protons flow into the matrix through ATP synthase, driving ADP phosphorylation.
کارت ۱۶۹
پرسش
Why do cells use stepwise electron transfers?
پاسخ
They release energy in manageable increments that can be captured instead of lost mostly as heat.
کارت ۱۷۰
پرسش
What is a cofactor?
پاسخ
A nonprotein helper, often a metal ion or small organic coenzyme, required for some enzymes to function.
کارت ۱۷۱
پرسش
What are the three broad phases of the Calvin cycle?
پاسخ
Carbon fixation, reduction, and regeneration of the carbon-dioxide acceptor RuBP.
کارت ۱۷۲
پرسش
How does lactic-acid fermentation regenerate NAD⁺?
پاسخ
NADH reduces pyruvate to lactate, returning electrons to form NAD⁺.
کارت ۱۷۳
پرسش
What is substrate-level phosphorylation?
پاسخ
An enzyme transfers a phosphate directly from an intermediate to ADP.
کارت ۱۷۴
پرسش
Error bars overlap broadly between two treatments. What is a careful conclusion?
پاسخ
The graph alone does not show a clear difference; a suitable statistical analysis and design context are still needed.
کارت ۱۷۵
پرسش
Why run an enzyme assay without enzyme?
پاسخ
It measures the uncatalyzed background change and tests whether enzyme is required.
کارت ۱۷۶
پرسش
How does alcoholic fermentation regenerate NAD⁺?
پاسخ
Pyruvate loses carbon dioxide, and the remaining compound is reduced to ethanol as NADH becomes NAD⁺.
کارت ۱۷۷
پرسش
What is G3P's role in photosynthesis?
پاسخ
It is a three-carbon product that can leave the Calvin cycle and help build carbohydrates.
کارت ۱۷۸
پرسش
Why are mitochondrial cristae useful?
پاسخ
They increase inner-membrane area for electron transport chains and ATP synthase.
کارت ۱۷۹
پرسش
What does phosphorylation often do to a molecule?
پاسخ
It adds a phosphate group that can increase reactivity or alter a protein's shape and activity.
کارت ۱۸۰
پرسش
A mutation lowers an enzyme's maximum rate but not substrate binding. What is a plausible effect?
پاسخ
It may impair a catalytic step or reduce the number of functional enzyme molecules.
کارت ۱۸۱
پرسش
Why must the Calvin cycle regenerate RuBP?
پاسخ
RuBP is the carbon-dioxide acceptor needed for another turn of fixation.
کارت ۱۸۲
پرسش
A chemical lowers oxygen use but not glycolysis. Which stage is most directly implicated?
پاسخ
Aerobic electron transport or a process supplying it, because glycolysis itself does not consume oxygen.
کارت ۱۸۳
پرسش
How would closed stomata affect photosynthesis?
پاسخ
Carbon dioxide entry falls, which can limit carbon fixation even when light is available.
کارت ۱۸۴
پرسش
A plant receives green light only. Predict its photosynthetic rate.
پاسخ
It will usually be lower than under equally intense red or blue light because common chlorophylls absorb green poorly.
کارت ۱۸۵
پرسش
Why does fermentation yield less ATP per glucose than aerobic respiration?
پاسخ
It relies on glycolysis alone and leaves much of glucose's chemical energy in reduced end products.
کارت ۱۸۶
پرسش
How does low ATP affect respiration pathway activity?
پاسخ
It usually relieves inhibition of key enzymes, increasing fuel oxidation and ATP production.
کارت ۱۸۷
پرسش
How can oxygen production estimate photosynthetic rate?
پاسخ
Oxygen is a light-reaction product, so its production per unit time can serve as a rate proxy under controlled conditions.
کارت ۱۸۸
پرسش
What happens to electron transport if oxygen is removed?
پاسخ
The chain backs up because electrons lack a final acceptor; NADH accumulates and oxidative phosphorylation stops.
کارت ۱۸۹
پرسش
Why does a light-response curve eventually level off?
پاسخ
Another factor, such as carbon dioxide supply, temperature, or enzyme capacity, becomes limiting.
کارت ۱۹۰
پرسش
An uncoupler lets protons cross the inner mitochondrial membrane. What happens?
پاسخ
The gradient weakens, ATP production falls, and more energy is released as heat even if electron transport continues.
کارت ۱۹۱
پرسش
What is direct-contact signaling?
پاسخ
A membrane-bound molecule or cell junction communicates with an adjacent cell.
کارت ۱۹۲
پرسش
What are the three broad stages of cell signaling?
پاسخ
Reception, transduction, and response.
کارت ۱۹۳
پرسش
How can a receptor mutation block a response even when ligand is present?
پاسخ
The receptor may fail to bind ligand, change shape, or activate the first relay protein.
کارت ۱۹۴
پرسش
What is negative feedback?
پاسخ
A response reduces the original stimulus, helping stabilize a variable near a functional range.
کارت ۱۹۵
پرسش
What happens during G1 phase?
پاسخ
The cell grows, performs normal functions, and prepares for DNA replication.
کارت ۱۹۶
پرسش
Cells show response values of 2, 7, and 18 after rising ligand doses. Describe the trend.
پاسخ
The response increases with ligand dose across the tested range.
کارت ۱۹۷
پرسش
What happens during reception?
پاسخ
A ligand binds its receptor and changes the receptor's activity or shape.
کارت ۱۹۸
پرسش
What is paracrine signaling?
پاسخ
A cell releases a local regulator that acts on nearby target cells.
کارت ۱۹۹
پرسش
What happens during S phase?
پاسخ
DNA is replicated, producing sister chromatids for each chromosome.
کارت ۲۰۰
پرسش
A response occurs without ligand. What pathway defect is plausible?
پاسخ
A receptor or downstream relay protein may be constitutively active.
کارت ۲۰۱
پرسش
What happens during signal transduction?
پاسخ
Intracellular steps relay and often amplify information from the activated receptor.
کارت ۲۰۲
پرسش
What is synaptic signaling?
پاسخ
A neuron releases neurotransmitter across a short synaptic gap to a target cell.
کارت ۲۰۳
پرسش
What happens during G2 phase?
پاسخ
The cell grows, checks replicated DNA, and prepares the machinery for division.
کارت ۲۰۴
پرسش
Why compare receptor-positive and receptor-negative cells?
پاسخ
The comparison tests whether the receptor is necessary for the observed response.
کارت ۲۰۵
پرسش
What counts as a cellular response?
پاسخ
A change in gene expression, enzyme activity, ion flow, secretion, movement, division, or another cell behavior.
کارت ۲۰۶
پرسش
How does insulin participate in negative feedback?
پاسخ
High blood glucose promotes insulin release, which lowers blood glucose and reduces the original stimulus.
کارت ۲۰۷
پرسش
What happens during mitosis?
پاسخ
A eukaryotic nucleus separates duplicated chromosomes into two nuclei.
کارت ۲۰۸
پرسش
What is endocrine signaling?
پاسخ
Hormones travel through circulatory fluid to target cells that may be far away.
کارت ۲۰۹
پرسش
What does a protein kinase do?
پاسخ
It transfers a phosphate from ATP to a target protein.
کارت ۲۱۰
پرسش
A drug blocks a kinase, and the final response disappears. What is supported?
پاسخ
The kinase is required somewhere in that pathway under the tested conditions.
کارت ۲۱۱
پرسش
What happens during cytokinesis?
پاسخ
The cytoplasm divides to form separate daughter cells.
کارت ۲۱۲
پرسش
How does glucagon participate in glucose homeostasis?
پاسخ
Low blood glucose promotes glucagon release, which raises blood glucose toward the normal range.
کارت ۲۱۳
پرسش
What does a protein phosphatase do?
پاسخ
It removes a phosphate group from a target protein.
کارت ۲۱۴
پرسش
What is a ligand?
پاسخ
A signaling molecule that binds specifically to a receptor.
کارت ۲۱۵
پرسش
What is the G1 checkpoint's broad role?
پاسخ
It checks size, nutrients, growth signals, and DNA condition before replication.
کارت ۲۱۶
پرسش
Why can't one inhibitor experiment prove a protein's exact pathway position?
پاسخ
Off-target effects and indirect dependencies can produce the same outcome.
کارت ۲۱۷
پرسش
Why are phosphorylation cascades reversible?
پاسخ
Kinases add phosphates, while phosphatases remove them and reset pathway components.
کارت ۲۱۸
پرسش
What is positive feedback?
پاسخ
A response strengthens the initiating stimulus until a separate event stops the loop.
کارت ۲۱۹
پرسش
What is the G2 checkpoint's broad role?
پاسخ
It checks whether DNA replication is complete and damage is repaired before mitosis.
کارت ۲۲۰
پرسش
Why don't all cells respond to the same hormone?
پاسخ
Only cells with a compatible receptor and response machinery can respond.
کارت ۲۲۱
پرسش
What is a second messenger?
پاسخ
A small intracellular molecule or ion that relays a signal after receptor activation.
کارت ۲۲۲
پرسش
How can rescue with an active downstream protein map a pathway?
پاسخ
If the response returns despite an upstream block, the rescued protein likely acts downstream of that block.
کارت ۲۲۳
پرسش
What does the spindle checkpoint verify?
پاسخ
Every chromosome is correctly attached to spindle microtubules before sister chromatids separate.
کارت ۲۲۴
پرسش
Why is blood clotting a positive-feedback process?
پاسخ
Activated platelets recruit and activate more platelets until the break is sealed.
کارت ۲۲۵
پرسش
Name two common second messengers.
پاسخ
Cyclic AMP and calcium ions.
کارت ۲۲۶
پرسش
A mutant receptor binds ligand but never becomes phosphorylated. Predict downstream signaling.
پاسخ
It will likely fall or disappear if receptor phosphorylation is required to recruit relay proteins.
کارت ۲۲۷
پرسش
How do cyclins regulate the cell cycle?
پاسخ
Their concentrations rise and fall, activating cyclin-dependent kinases at specific stages.
کارت ۲۲۸
پرسش
Why must DNA replicate before mitosis?
پاسخ
Each daughter nucleus needs a complete copy of the genome.
کارت ۲۲۹
پرسش
Where do receptors for many peptide hormones sit?
پاسخ
In the plasma membrane, because these polar ligands do not readily cross the lipid bilayer.
کارت ۲۳۰
پرسش
How can a signaling pathway amplify a weak signal?
پاسخ
One activated component activates many downstream molecules at successive steps.
کارت ۲۳۱
پرسش
What is the dependent variable in a ligand-dose experiment?
پاسخ
The measured response, such as reporter activity, enzyme phosphorylation, or ion concentration.
کارت ۲۳۲
پرسش
What do cyclin-dependent kinases do?
پاسخ
When paired with cyclins, they phosphorylate targets that drive cell-cycle transitions.
کارت ۲۳۳
پرسش
Why doesn't positive feedback usually maintain homeostasis by itself?
پاسخ
It drives change away from the starting state and needs an external stop.
کارت ۲۳۴
پرسش
What is a G protein's signaling role?
پاسخ
It switches activity when bound to GTP and relays information from certain membrane receptors to effectors.
کارت ۲۳۵
پرسش
How would you test whether calcium is required for a response?
پاسخ
Block the calcium rise while keeping other conditions matched, then compare the response with a vehicle control.
کارت ۲۳۶
پرسش
What is apoptosis?
پاسخ
Programmed cell death that dismantles a cell in a controlled way.
کارت ۲۳۷
پرسش
Where are receptors for many steroid hormones?
پاسخ
Inside the cell, where lipid-soluble hormones can bind after crossing the membrane.
کارت ۲۳۸
پرسش
How can an ion-channel receptor create a rapid response?
پاسخ
Ligand binding opens or closes a pore, quickly changing ion movement and membrane conditions.
کارت ۲۳۹
پرسش
Why test several ligand concentrations?
پاسخ
A dose–response series can reveal sensitivity, saturation, and whether effects scale with ligand.
کارت ۲۴۰
پرسش
Why is apoptosis useful in multicellular organisms?
پاسخ
It removes damaged, infected, or unneeded cells with limited harm to neighbors.
کارت ۲۴۱
پرسش
A thermostat-like pathway overshoots repeatedly. What defect is plausible?
پاسخ
Delayed sensing or response can make negative feedback correct too late.
کارت ۲۴۲
پرسش
How can an intracellular receptor affect gene expression?
پاسخ
The ligand–receptor complex can act directly or indirectly as a transcription regulator.
کارت ۲۴۳
پرسش
Cells lacking protein X divide despite DNA damage. Justify a checkpoint claim.
پاسخ
Protein X likely supports a DNA-damage checkpoint because its absence links damage with continued division; rescue or pathway tests would strengthen the claim.
کارت ۲۴۴
پرسش
What aligns at the metaphase plate?
پاسخ
Duplicated chromosomes attached to spindle microtubules from opposite poles.
کارت ۲۴۵
پرسش
How can failed checkpoints contribute to cancer?
پاسخ
Cells with damage or abnormal signals can keep dividing instead of pausing or dying.
کارت ۲۴۶
پرسش
How can gap junctions support communication?
پاسخ
They connect neighboring animal-cell cytoplasms so small molecules and ions can pass directly.
کارت ۲۴۷
پرسش
Why can the same ligand trigger different responses in two cell types?
پاسخ
The cells can express different receptors, relay proteins, targets, or genes.
کارت ۲۴۸
پرسش
Two pathways share one relay protein. What can happen if that protein is blocked?
پاسخ
Both responses may weaken, showing pathway crosstalk or a shared component.
کارت ۲۴۹
پرسش
During which mitotic stage do sister chromatids separate?
پاسخ
Anaphase.
کارت ۲۵۰
پرسش
What defines a malignant tumor?
پاسخ
Its cells invade surrounding tissue and may spread to distant sites.
کارت ۲۵۱
پرسش
How would loss of a feedback inhibitor affect a biosynthetic pathway?
پاسخ
The pathway may stay active and overproduce its end product.
کارت ۲۵۲
پرسش
What ends a signaling response?
پاسخ
Ligand removal, receptor inactivation, GTP hydrolysis, messenger breakdown, or dephosphorylation can shut it down.
کارت ۲۵۳
پرسش
A pathway diagram shows A activates B, and B inhibits C. Predict C after A activation.
پاسخ
C activity should decrease, assuming the shown links are the relevant controlling interactions.
کارت ۲۵۴
پرسش
A phosphatase that normally turns off an activated relay protein is inhibited. Predict the effect on that pathway.
پاسخ
Phosphorylated targets may stay active longer, extending or strengthening the response.
کارت ۲۵۵
پرسش
A drug prevents spindle formation. Where should the cycle stop?
پاسخ
At the spindle checkpoint before anaphase, because chromosomes cannot attach correctly.
کارت ۲۵۶
پرسش
What is the purpose of meiosis?
پاسخ
It produces haploid cells and reshuffles inherited alleles for sexual reproduction.
کارت ۲۵۷
پرسش
What is crossing over?
پاسخ
Exchange of corresponding DNA segments between nonsister chromatids of homologous chromosomes.
کارت ۲۵۸
پرسش
What does Mendel's law of segregation describe?
پاسخ
An individual's two alleles for a gene separate into different gametes.
کارت ۲۵۹
پرسش
Why do X-linked recessive traits often appear more frequently in XY individuals?
پاسخ
They have only one X chromosome, so one recessive allele on it can determine the phenotype.
کارت ۲۶۰
پرسش
What is incomplete dominance?
پاسخ
The heterozygote has a phenotype intermediate between the two homozygotes.
کارت ۲۶۱
پرسش
What does a chi-square goodness-of-fit test compare?
پاسخ
Observed category counts with counts expected under a stated model.
کارت ۲۶۲
پرسش
What is a homologous chromosome pair?
پاسخ
Two chromosomes carrying the same gene locations, one inherited from each parent, possibly with different alleles.
کارت ۲۶۳
پرسش
What does Mendel's law of independent assortment describe?
پاسخ
Alleles of genes on different chromosomes, or far apart on one chromosome, assort independently during gamete formation.
کارت ۲۶۴
پرسش
What is genetic linkage?
پاسخ
Genes close together on the same chromosome tend to be inherited together.
کارت ۲۶۵
پرسش
When does crossing over occur?
پاسخ
During prophase I after homologs pair.
کارت ۲۶۶
پرسش
How do sister chromatids differ from homologous chromosomes?
پاسخ
Sister chromatids are replicated copies of one chromosome; homologs are the maternal and paternal versions of the same chromosome type.
کارت ۲۶۷
پرسش
For Aa × Aa, what is the expected genotype ratio?
پاسخ
1 AA : 2 Aa : 1 aa.
کارت ۲۶۸
پرسش
How can linked genes produce recombinant offspring?
پاسخ
Crossing over can exchange DNA between the gene locations.
کارت ۲۶۹
پرسش
What is the usual null hypothesis for a Mendelian chi-square test?
پاسخ
Any difference between observed and expected counts is due to chance sampling under the proposed inheritance model.
کارت ۲۷۰
پرسش
What happens to homologous chromosomes in meiosis I?
پاسخ
They pair and then separate into different cells.
۵۴۰ کارت
AP Biology Flashcards: Complete 8-Unit Course Review
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کارت ۲۷۱
پرسش
For Aa × Aa with complete dominance, what is the expected phenotype ratio?
پاسخ
3 dominant phenotype : 1 recessive phenotype.
کارت ۲۷۲
پرسش
How does crossing over increase variation?
پاسخ
It creates chromosomes with new combinations of parental alleles.
کارت ۲۷۳
پرسش
What does recombination frequency estimate?
پاسخ
Relative distance between linked genes; higher frequency generally means greater separation, up to the 50% limit.
کارت ۲۷۴
پرسش
What happens to sister chromatids in meiosis II?
پاسخ
Their centromeres separate, and the chromatids move into different cells.
کارت ۲۷۵
پرسش
What rule finds the probability of either of two mutually exclusive outcomes?
پاسخ
Add their individual probabilities.
کارت ۲۷۶
پرسش
What is codominance?
پاسخ
Both alleles contribute distinct, detectable products or traits in the heterozygote.
کارت ۲۷۷
پرسش
How is a chi-square contribution calculated for one category?
پاسخ
Subtract expected from observed, square the difference, and divide by expected.
کارت ۲۷۸
پرسش
When do homologous chromosomes pair as tetrads?
پاسخ
During prophase I.
کارت ۲۷۹
پرسش
What rule finds the probability that independent events both occur?
پاسخ
Multiply their individual probabilities.
کارت ۲۸۰
پرسش
What is independent assortment?
پاسخ
Each homologous pair orients independently at metaphase I, producing many maternal–paternal chromosome combinations.
کارت ۲۸۱
پرسش
Why can't recombination frequency exceed 50%?
پاسخ
At 50%, recombinant and parental combinations are equally common and the genes behave as if unlinked.
کارت ۲۸۲
پرسش
What aligns at the metaphase I plate?
پاسخ
Homologous pairs, with each homolog attached toward an opposite pole.
کارت ۲۸۳
پرسش
What is a test cross?
پاسخ
Crossing an individual with a dominant phenotype to a homozygous recessive individual to infer the unknown genotype.
کارت ۲۸۴
پرسش
How can one gene have multiple alleles?
پاسخ
More than two allele forms can exist in the population, although one diploid individual carries at most two.
کارت ۲۸۵
پرسش
How are total chi-square and category contributions related?
پاسخ
Total chi-square is the sum of all category contributions.
کارت ۲۸۶
پرسش
What separates during anaphase I?
پاسخ
Homologous chromosomes; sister chromatids remain joined.
کارت ۲۸۷
پرسش
How does random fertilization increase variation?
پاسخ
Any one genetically varied gamete from one parent can fuse with any compatible gamete from the other.
کارت ۲۸۸
پرسش
A test cross yields about half recessive offspring. What genotype is supported for the unknown parent?
پاسخ
Heterozygous.
کارت ۲۸۹
پرسش
What is nondisjunction?
پاسخ
Failure of homologous chromosomes or sister chromatids to separate normally.
کارت ۲۹۰
پرسش
What aligns during metaphase II?
پاسخ
Individual duplicated chromosomes in each haploid cell.
کارت ۲۹۱
پرسش
What is polygenic inheritance?
پاسخ
Multiple genes contribute to one trait, often producing continuous phenotypic variation.
کارت ۲۹۲
پرسش
For a simple goodness-of-fit test, how are degrees of freedom found?
پاسخ
Number of categories minus one.
کارت ۲۹۳
پرسش
Which meiotic events create variation before fertilization?
پاسخ
Crossing over and independent assortment.
کارت ۲۹۴
پرسش
How does ploidy change during meiosis?
پاسخ
Homolog separation reduces diploid cells to haploid cells; meiosis II separates chromatids without another ploidy reduction.
کارت ۲۹۵
پرسش
What pedigree pattern often suggests a recessive trait?
پاسخ
Unaffected parents can have an affected child, if both parents carry the allele.
کارت ۲۹۶
پرسش
How can meiotic nondisjunction affect gametes?
پاسخ
It can produce gametes with an extra or missing chromosome.
کارت ۲۹۷
پرسش
What is pleiotropy?
پاسخ
One gene influences multiple phenotypic traits.
کارت ۲۹۸
پرسش
Why is there no second DNA replication before meiosis II?
پاسخ
The goal is to separate existing sister chromatids, not duplicate the genome again.
کارت ۲۹۹
پرسش
What does a p-value below the chosen threshold support?
پاسخ
Rejecting the null model because the observed deviation would be unlikely if that model were correct.
کارت ۳۰۰
پرسش
Why are siblings genetically different even with the same parents?
پاسخ
They inherit different allele combinations through crossing over, independent assortment, and random fertilization.
کارت ۳۰۱
پرسش
Why do small families often deviate from expected Mendelian ratios?
پاسخ
Probability ratios describe long-run expectations; random sampling variation is large with few offspring.
کارت ۳۰۲
پرسش
A diploid cell has six chromosomes. How many chromosomes should each normal meiotic product have?
پاسخ
Three.
کارت ۳۰۳
پرسش
A trisomic zygote forms after fertilization. What meiotic error is a likely cause?
پاسخ
Nondisjunction produced a gamete carrying an extra copy of that chromosome.
کارت ۳۰۴
پرسش
Why can identical genotypes show different phenotypes?
پاسخ
Environmental conditions and developmental variation can alter gene expression or trait development.
کارت ۳۰۵
پرسش
What does failing to reject a genetic null hypothesis mean?
پاسخ
The data do not show a significant departure from the model; they do not prove the model true.
کارت ۳۰۶
پرسش
How do DNA and RNA sugars differ?
پاسخ
DNA contains deoxyribose; RNA contains ribose.
کارت ۳۰۷
پرسش
What does semiconservative DNA replication produce?
پاسخ
Each daughter DNA molecule contains one original strand and one newly synthesized strand.
کارت ۳۰۸
پرسش
What is transcription?
پاسخ
Synthesis of RNA using DNA as a template.
کارت ۳۰۹
پرسش
What is a point mutation?
پاسخ
A change affecting one nucleotide pair.
کارت ۳۱۰
پرسش
What is an operon?
پاسخ
A group of prokaryotic genes controlled together and transcribed from one promoter.
کارت ۳۱۱
پرسش
Why can muscle and nerve cells differ despite having the same genome?
پاسخ
They express different sets and amounts of genes.
کارت ۳۱۲
پرسش
What must a virus use from its host?
پاسخ
Host resources and at least some host-cell machinery to copy or express its genome and produce new particles.
کارت ۳۱۳
پرسش
What does PCR do?
پاسخ
It amplifies a chosen DNA region through repeated cycles of strand separation, primer binding, and extension.
کارت ۳۱۴
پرسش
What enzyme performs transcription?
پاسخ
RNA polymerase.
کارت ۳۱۵
پرسش
What does helicase do during replication?
پاسخ
It unwinds the double helix and separates the template strands.
کارت ۳۱۶
پرسش
How does a repressor reduce transcription?
پاسخ
It binds regulatory DNA and blocks or hinders transcription machinery.
کارت ۳۱۷
پرسش
What is a silent mutation?
پاسخ
A nucleotide change that does not change the encoded amino acid.
کارت ۳۱۸
پرسش
What does a promoter do?
پاسخ
It marks where transcription machinery assembles and helps set the transcription start and direction.
کارت ۳۱۹
پرسش
What does topoisomerase do ahead of a replication fork?
پاسخ
It relieves twisting strain caused by DNA unwinding.
کارت ۳۲۰
پرسش
How does an inducer affect an inducible operon?
پاسخ
It disables the repressor or otherwise turns transcription on when the pathway's substrate is present.
کارت ۳۲۱
پرسش
How do DNA and RNA bases differ?
پاسخ
DNA uses thymine, while RNA uses uracil; both also use adenine, cytosine, and guanine.
کارت ۳۲۲
پرسش
Which DNA strand does RNA polymerase read?
پاسخ
The template strand, read 3′→5′ while RNA is built 5′→3′.
کارت ۳۲۳
پرسش
Why is an RNA primer needed for DNA replication?
پاسخ
DNA polymerase can extend an existing 3′ end but cannot start a strand from nothing.
کارت ۳۲۴
پرسش
How does a corepressor affect a repressible operon?
پاسخ
It activates a repressor, turning off genes when the pathway's end product is abundant.
کارت ۳۲۵
پرسش
What is a missense mutation?
پاسخ
A nucleotide change that substitutes one amino acid for another.
کارت ۳۲۶
پرسش
How does an mRNA sequence relate to the coding DNA strand?
پاسخ
It matches the coding strand except RNA has uracil in place of thymine.
کارت ۳۲۷
پرسش
What does primase do?
پاسخ
It builds short RNA primers.
کارت ۳۲۸
پرسش
Why is the lac operon strongly expressed when lactose is present and glucose is scarce?
پاسخ
Lactose relieves repression, while low glucose supports positive activation of transcription.
کارت ۳۲۹
پرسش
Why are primers essential in PCR?
پاسخ
They define the target boundaries and provide 3′ ends for DNA polymerase.
کارت ۳۳۰
پرسش
What is the primary RNA transcript in a eukaryote?
پاسخ
The initial RNA copy before processing.
کارت ۳۳۱
پرسش
In which direction does DNA polymerase synthesize DNA?
پاسخ
5′→3′ by adding nucleotides to a 3′ end.
کارت ۳۳۲
پرسش
Why is the trp operon usually off when tryptophan is abundant?
پاسخ
Tryptophan acts as a corepressor, enabling repression of biosynthetic genes.
کارت ۳۳۳
پرسش
What holds complementary DNA bases together?
پاسخ
Hydrogen bonds: adenine pairs with thymine, and cytosine pairs with guanine.
کارت ۳۳۴
پرسش
What happens during RNA splicing?
پاسخ
Introns are removed and exons are joined.
کارت ۳۳۵
پرسش
Why is the leading strand synthesized continuously?
پاسخ
Its template orientation lets polymerase follow the replication fork while synthesizing 5′→3′.
کارت ۳۳۶
پرسش
How can histone acetylation affect transcription?
پاسخ
It often loosens chromatin and makes DNA more accessible to transcription machinery.
کارت ۳۳۷
پرسش
What is a nonsense mutation?
پاسخ
A nucleotide change that creates a premature stop codon.
کارت ۳۳۸
پرسش
What do the 5′ cap and poly-A tail help do?
پاسخ
They protect eukaryotic mRNA and support export and translation.
کارت ۳۳۹
پرسش
Why is the lagging strand synthesized in fragments?
پاسخ
Its template orientation forces repeated 5′→3′ synthesis away from the moving fork.
کارت ۳۴۰
پرسش
How can DNA methylation near a promoter affect transcription?
پاسخ
It often reduces transcription by limiting access or recruiting repressive proteins.
کارت ۳۴۱
پرسش
How does gel electrophoresis separate DNA fragments?
پاسخ
An electric field pulls negatively charged DNA through a matrix; smaller fragments usually travel farther.
کارت ۳۴۲
پرسش
How can alternative splicing increase protein diversity?
پاسخ
Different exon combinations from one transcript can produce different mRNAs and polypeptides.
کارت ۳۴۳
پرسش
What are Okazaki fragments?
پاسخ
Short DNA segments made on the lagging strand.
کارت ۳۴۴
پرسش
What does a transcription factor do?
پاسخ
It binds regulatory DNA and helps increase or decrease transcription of specific genes.
کارت ۳۴۵
پرسش
Why are DNA strands antiparallel?
پاسخ
Their sugar–phosphate backbones run in opposite 5′→3′ directions.
کارت ۳۴۶
پرسش
What is translation?
پاسخ
Ribosomes use an mRNA codon sequence to build a polypeptide.
کارت ۳۴۷
پرسش
What does DNA ligase do?
پاسخ
It seals breaks in the sugar–phosphate backbone, joining DNA fragments.
کارت ۳۴۸
پرسش
What is a frameshift mutation?
پاسخ
An insertion or deletion not in multiples of three that shifts downstream codon grouping.
کارت ۳۴۹
پرسش
How can an enhancer influence a distant promoter?
پاسخ
DNA looping brings enhancer-bound activators near the transcription machinery.
کارت ۳۵۰
پرسش
What does a codon specify?
پاسخ
An amino acid or a translation stop signal.
کارت ۳۵۱
پرسش
What do restriction enzymes do?
پاسخ
They cut DNA at particular recognition sequences.
کارت ۳۵۲
پرسش
What gives a nucleic-acid strand its 5′ and 3′ ends?
پاسخ
The chemical groups on the sugar: a 5′ phosphate end and a 3′ hydroxyl end.
کارت ۳۵۳
پرسش
How does proofreading improve replication accuracy?
پاسخ
DNA polymerases detect and replace many incorrectly paired nucleotides.
کارت ۳۵۴
پرسش
What does a tRNA anticodon do?
پاسخ
It base-pairs with an mRNA codon so the attached amino acid is placed correctly.
کارت ۳۵۵
پرسش
Why can a promoter mutation affect protein amount?
پاسخ
It can change transcription-factor or RNA-polymerase binding and alter transcription rate.
کارت ۳۵۶
پرسش
How can microRNA reduce gene expression?
پاسخ
It base-pairs with target mRNA and promotes degradation or blocks translation.
کارت ۳۵۷
پرسش
What maintains a differentiated cell's identity?
پاسخ
Stable regulatory networks and chromatin states keep characteristic genes active or silent.
کارت ۳۵۸
پرسش
What are the ribosome's broad roles?
پاسخ
It positions mRNA and tRNAs and catalyzes peptide-bond formation.
کارت ۳۵۹
پرسش
How can an RNA virus generate genetic variation quickly?
پاسخ
Many viral RNA polymerases lack strong proofreading, so replication introduces mutations frequently.
کارت ۳۶۰
پرسش
What can bacterial transformation demonstrate?
پاسخ
Cells can take up external DNA and express a selectable or observable trait.
کارت ۳۶۱
پرسش
Why is RNA usually more structurally varied than double-stranded DNA?
پاسخ
A single RNA strand can fold back on itself through internal base pairing.
کارت ۳۶۲
پرسش
What usually marks translation initiation?
پاسخ
A start codon positioned with an initiator tRNA and ribosomal subunits.
کارت ۳۶۳
پرسش
What problem do telomeres help solve?
پاسخ
They protect chromosome ends from losing essential genes during repeated linear-DNA replication.
کارت ۳۶۴
پرسش
Why can an intron splice-site mutation affect protein sequence?
پاسخ
Incorrect splicing can remove exon sequence or retain intron sequence in the mature mRNA.
کارت ۳۶۵
پرسش
How can protein degradation regulate a pathway quickly?
پاسخ
Destroying a key protein lowers its activity without waiting for transcription to change.
کارت ۳۶۶
پرسش
What happens at a stop codon?
پاسخ
A release factor ends translation and frees the polypeptide.
کارت ۳۶۷
پرسش
How can a signal change cell specialization?
پاسخ
It can activate transcription factors that launch a new gene-expression program.
کارت ۳۶۸
پرسش
What is a retrovirus's information flow?
پاسخ
Viral RNA is reverse-transcribed into DNA, which can integrate into the host genome.
کارت ۳۶۹
پرسش
What does DNA sequencing reveal directly?
پاسخ
The order of nucleotides in the analyzed DNA; biological effects require further interpretation.
کارت ۳۷۰
پرسش
Why is the genetic code called redundant?
پاسخ
More than one codon can specify the same amino acid.
کارت ۳۷۱
پرسش
Where does nucleotide sequence store information?
پاسخ
The order of bases encodes information that can be copied, transcribed, or translated.
کارت ۳۷۲
پرسش
Why is replication called bidirectional?
پاسخ
Two forks usually move away from each origin in opposite directions.
کارت ۳۷۳
پرسش
Why doesn't every DNA mutation change phenotype?
پاسخ
It may occur outside a functional sequence, be silent, have a mild effect, or be masked by another allele or environment.
کارت ۳۷۴
پرسش
How does a free ribosome's product usually differ from a rough-ER ribosome's product?
پاسخ
Free ribosomes often make cytosolic proteins; ER-bound ribosomes make many secreted, membrane, and endomembrane proteins.
کارت ۳۷۵
پرسش
Why can one signal coordinate many genes?
پاسخ
A shared transcription regulator or signaling pathway can control multiple target promoters.
کارت ۳۷۶
پرسش
Why does cell specialization depend on selective gene expression rather than gene loss?
پاسخ
Most specialized cells retain the genome but use only the genes needed for their role.
کارت ۳۷۷
پرسش
Why are viruses not described as independently living cells?
پاسخ
They lack cellular metabolism and cannot reproduce without a host cell.
کارت ۳۷۸
پرسش
A coding DNA triplet is 5′-ATG-3′. What is the matching mRNA codon?
پاسخ
5′-AUG-3′.
کارت ۳۷۹
پرسش
A PCR band is absent. Why isn't gene absence the only explanation?
پاسخ
Poor DNA quality, wrong primers, inhibitors, or failed reaction conditions can also prevent amplification.
کارت ۳۸۰
پرسش
Why can protein function require steps after translation?
پاسخ
The polypeptide may need folding, cleavage, chemical modification, or assembly with other subunits.
کارت ۳۸۱
پرسش
How do fossils support evolution?
پاسخ
They document organisms and transitions through time, including appearance, change, and extinction.
کارت ۳۸۲
پرسش
What conditions are required for natural selection?
پاسخ
Individuals vary, some variation is heritable, and variants differ in survival or reproductive success in that environment.
کارت ۳۸۳
پرسش
What is artificial selection?
پاسخ
Humans choose which organisms reproduce based on desired heritable traits.
کارت ۳۸۴
پرسش
What does an allele frequency measure?
پاسخ
The fraction of all copies of a gene in a population represented by one allele.
کارت ۳۸۵
پرسش
What does a node on a phylogenetic tree represent?
پاسخ
A common ancestor where descendant lineages diverge.
کارت ۳۸۶
پرسش
What is biological speciation?
پاسخ
Evolution of reproductive isolation between populations, producing independently evolving lineages.
کارت ۳۸۷
پرسش
What is extinction?
پاسخ
Permanent loss of a species when no living members remain.
کارت ۳۸۸
پرسش
A pesticide-treated population becomes mostly resistant. What evidence distinguishes selection from acclimation?
پاسخ
Resistance should be heritable and increase across generations through differential reproduction, not just appear temporarily in exposed individuals.
کارت ۳۸۹
پرسش
What changes during evolution by natural selection?
پاسخ
Allele frequencies in a population across generations.
کارت ۳۹۰
پرسش
For two alleles under Hardy–Weinberg notation, what does p + q equal?
پاسخ
1.
کارت ۳۹۱
پرسش
What is a clade?
پاسخ
An ancestor and all of its descendants.
کارت ۳۹۲
پرسش
What does homologous anatomy suggest?
پاسخ
Similar underlying structures with different functions can indicate inheritance from a common ancestor.
کارت ۳۹۳
پرسش
Do individual organisms evolve by natural selection?
پاسخ
No. Individuals are selected; populations evolve as inherited variants change in frequency.
کارت ۳۹۴
پرسش
Under Hardy–Weinberg equilibrium, what does p² represent?
پاسخ
Expected frequency of one homozygous genotype.
کارت ۳۹۵
پرسش
What is a shared derived character?
پاسخ
A trait that evolved in a common ancestor and helps identify one of its descendant clades.
کارت ۳۹۶
پرسش
What is mutation's evolutionary role?
پاسخ
It creates new alleles, the ultimate source of new genetic variation.
کارت ۳۹۷
پرسش
What is biological fitness?
پاسخ
Relative contribution of viable, reproducing offspring to the next generation in a particular environment.
کارت ۳۹۸
پرسش
Under Hardy–Weinberg equilibrium, what does 2pq represent?
پاسخ
Expected frequency of heterozygotes.
کارت ۳۹۹
پرسش
Which two tips on a tree are most closely related?
پاسخ
Those sharing the most recent common ancestor, regardless of how close their names appear on the page.
کارت ۴۰۰
پرسش
What is a vestigial structure?
پاسخ
A reduced feature inherited from ancestors that has lost much or all of its earlier function.
کارت ۴۰۱
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What is an adaptation?
پاسخ
A heritable trait that became common because it improved fitness in past environments.
کارت ۴۰۲
پرسش
Under Hardy–Weinberg equilibrium, what does q² represent?
پاسخ
Expected frequency of the other homozygous genotype.
کارت ۴۰۳
پرسش
How does recombination affect evolution?
پاسخ
It reshuffles existing alleles into new combinations but does not itself create new alleles.
کارت ۴۰۴
پرسش
Does rotating branches around a node change relationships?
پاسخ
No. The branching pattern stays the same.
کارت ۴۰۵
پرسش
Why isn't an adaptation always beneficial in every setting?
پاسخ
Fitness effects depend on the environment and can involve tradeoffs.
کارت ۴۰۶
پرسش
What are the Hardy–Weinberg assumptions?
پاسخ
A very large population, random mating, no mutation, no migration, and no natural selection at the locus.
کارت ۴۰۷
پرسش
How can embryological similarities support common ancestry?
پاسخ
Shared developmental patterns can reflect inherited developmental genes and pathways.
کارت ۴۰۸
پرسش
What is gene flow?
پاسخ
Movement of alleles between populations through migration and reproduction.
کارت ۴۰۹
پرسش
Does natural selection create needed mutations?
پاسخ
No. Mutations arise without regard to need; selection changes the frequencies of their inherited effects.
کارت ۴۱۰
پرسش
Why is Hardy–Weinberg equilibrium useful?
پاسخ
It provides a null model for detecting or reasoning about evolutionary change.
کارت ۴۱۱
پرسش
Does left-to-right tip order show evolutionary progress?
پاسخ
No. Tip order is a drawing choice, not a ranking from primitive to advanced.
کارت ۴۱۲
پرسش
What is allopatric speciation?
پاسخ
Geographic separation reduces gene flow, allowing populations to diverge.
کارت ۴۱۳
پرسش
What is directional selection?
پاسخ
Selection favors one end of a phenotypic range, shifting the population mean.
کارت ۴۱۴
پرسش
If q² = 0.09, what is q?
پاسخ
0.30.
کارت ۴۱۵
پرسش
Why is DNA sequence similarity evidence for relatedness?
پاسخ
Related lineages inherit sequences from common ancestors, with differences accumulating over time.
کارت ۴۱۶
پرسش
How does gene flow often affect differences between populations?
پاسخ
It tends to make allele frequencies more similar.
کارت ۴۱۷
پرسش
What is stabilizing selection?
پاسخ
Selection favors intermediate phenotypes and removes extremes.
کارت ۴۱۸
پرسش
If q = 0.30, what is p?
پاسخ
0.70.
کارت ۴۱۹
پرسش
What can branch length mean?
پاسخ
Only what the figure defines—sometimes time or amount of change, and sometimes nothing quantitative.
کارت ۴۲۰
پرسش
What is sympatric speciation?
پاسخ
Reproductive isolation evolves without geographic separation, for example through polyploidy or strong niche and mating differences.
کارت ۴۲۱
پرسش
What is disruptive selection?
پاسخ
Selection favors both extremes over intermediate phenotypes.
کارت ۴۲۲
پرسش
If p = 0.70 and q = 0.30, what is 2pq?
پاسخ
0.42.
کارت ۴۲۳
پرسش
Why include an untreated population in a selection experiment?
پاسخ
It shows how allele or trait frequencies change without the selective treatment.
کارت ۴۲۴
پرسش
Why is the nearly universal genetic code evidence of common ancestry?
پاسخ
A deeply conserved information system is most simply explained by inheritance from early shared ancestors.
کارت ۴۲۵
پرسش
What is balancing selection?
پاسخ
Natural selection that maintains two or more alleles in a population, such as through heterozygote advantage or selection that varies across environments.
کارت ۴۲۶
پرسش
What is genetic drift?
پاسخ
Random change in allele frequencies caused by chance sampling across generations.
کارت ۴۲۷
پرسش
If 16% of a Hardy–Weinberg population shows a recessive phenotype, what is q?
پاسخ
0.40, because q is the square root of 0.16.
کارت ۴۲۸
پرسش
Why use an outgroup in tree analysis?
پاسخ
It helps infer which character states are ancestral versus derived in the focal group.
کارت ۴۲۹
پرسش
What is a prezygotic barrier?
پاسخ
A barrier that prevents mating or fertilization.
کارت ۴۳۰
پرسش
Allele A rises from 0.20 to 0.45. Describe the evolutionary result.
پاسخ
The population evolved at that locus because allele frequency changed.
کارت ۴۳۱
پرسش
How does biogeography support evolution?
پاسخ
Species distributions often match isolation history, dispersal, and descent from nearby ancestors.
کارت ۴۳۲
پرسش
What is sexual selection?
پاسخ
Differences in mating success drive changes in traits that affect mate attraction or competition.
کارت ۴۳۳
پرسش
When is genetic drift strongest?
پاسخ
In small populations.
کارت ۴۳۴
پرسش
Why can a rare recessive allele persist?
پاسخ
Selection cannot remove copies hidden in heterozygotes as efficiently as copies expressed in homozygotes.
کارت ۴۳۵
پرسش
How can molecular data revise a phylogenetic tree?
پاسخ
Sequence comparisons can reveal relationships not obvious from morphology or distinguish convergence from homology.
کارت ۴۳۶
پرسش
What is a postzygotic barrier?
پاسخ
A barrier that reduces hybrid survival, fertility, or later-generation success after fertilization.
کارت ۴۳۷
پرسش
How can rapid environmental change increase extinction risk?
پاسخ
Populations may lack enough suitable variation or time to adapt or move.
کارت ۴۳۸
پرسش
A small island population loses alleles after a storm. Which mechanism is most direct?
پاسخ
Genetic drift through a bottleneck.
کارت ۴۳۹
پرسش
What is convergent evolution?
پاسخ
Unrelated lineages independently evolve similar traits under similar selective pressures.
کارت ۴۴۰
پرسش
Why can antibiotic resistance spread rapidly?
پاسخ
Treatment strongly favors resistant variants already present or newly introduced, which leave more descendants.
کارت ۴۴۱
پرسش
What is a bottleneck effect?
پاسخ
A sharp population reduction leaves a random, often less diverse sample of the original gene pool.
کارت ۴۴۲
پرسش
How do genotype counts yield allele frequency?
پاسخ
Count two copies from each homozygote and one from each heterozygote, then divide by twice the number of diploid individuals.
کارت ۴۴۳
پرسش
What is maximum parsimony in tree building?
پاسخ
Preferring the tree that requires the fewest evolutionary changes under the model.
کارت ۴۴۴
پرسش
How can different breeding times isolate populations?
پاسخ
Temporal isolation prevents individuals from mating even when they share a location.
کارت ۴۴۵
پرسش
Why can mass extinctions reshape evolution?
پاسخ
They remove many lineages and open ecological opportunities for survivors.
کارت ۴۴۶
پرسش
Two similar traits evolved on distant tree branches. What explanation should be evaluated?
پاسخ
Convergent evolution under similar selection, alongside the possibility of an incorrect tree or unrecognized homology.
کارت ۴۴۷
پرسش
Why are analogous structures weak evidence of close ancestry?
پاسخ
Their similar function may have evolved independently rather than from the same ancestral structure.
کارت ۴۴۸
پرسش
Why doesn't natural selection produce perfection?
پاسخ
It works with existing variation under tradeoffs, historical constraints, chance, and changing environments.
کارت ۴۴۹
پرسش
What is a founder effect?
پاسخ
A new population starts from a small, nonrepresentative sample of a source population.
کارت ۴۵۰
پرسش
Observed genotypes differ from Hardy–Weinberg expectations. What is supported?
پاسخ
At least one model assumption may not hold, or sampling error may matter; the deviation alone does not identify the cause.
کارت ۴۵۱
پرسش
Why is a phylogenetic tree a hypothesis?
پاسخ
It is an evidence-based reconstruction that can change when new data or methods appear.
کارت ۴۵۲
پرسش
How can behavioral differences cause isolation?
پاسخ
Different courtship signals reduce mating between populations.
کارت ۴۵۳
پرسش
What evidence can test origin-of-life hypotheses?
پاسخ
Chemistry experiments, geological records, molecular comparisons, and plausible self-replicating or membrane-forming systems.
کارت ۴۵۴
پرسش
How should fitness be compared in an experiment?
پاسخ
Measure relative reproductive contribution, such as viable offspring, under the same environmental conditions.
کارت ۴۵۵
پرسش
What does the fossil record not provide?
پاسخ
A complete sample of every organism or every transitional population.
کارت ۴۵۶
پرسش
How can a neutral trait change in frequency?
پاسخ
Genetic drift can shift it by chance, especially in small populations.
کارت ۴۵۷
پرسش
How can drift reduce adaptive potential?
پاسخ
It can remove alleles and lower genetic diversity needed under future environmental change.
کارت ۴۵۸
پرسش
Why does a large population support Hardy–Weinberg stability?
پاسخ
Chance sampling has less effect on allele frequencies, reducing drift.
کارت ۴۵۹
پرسش
If A and B share a more recent node with each other than either shares with C, what does that mean?
پاسخ
A and B are sister taxa and share a more recent common ancestor with each other than with C.
کارت ۴۶۰
پرسش
What is adaptive radiation?
پاسخ
Rapid diversification of one ancestral lineage into species using different ecological roles.
کارت ۴۶۱
پرسش
What can experiments producing organic molecules from simple chemicals show?
پاسخ
That some building blocks can form under modeled conditions; they do not recreate or prove the exact origin of life.
کارت ۴۶۲
پرسش
A correlation links beak size with survival. Why isn't causation settled?
پاسخ
Other traits or habitats may covary with beak size; controlled or multivariable evidence is needed.
کارت ۴۶۳
پرسش
Why does agreement among fossils, anatomy, and molecules strengthen an evolutionary claim?
پاسخ
Independent evidence types pointing to the same history make alternative explanations less plausible.
کارت ۴۶۴
پرسش
A drought favors deeper beaks. What must be measured to show selection?
پاسخ
Heritable beak variation and differences in survival or reproduction linked to beak depth.
کارت ۴۶۵
پرسش
Why can artificial selection produce unintended traits?
پاسخ
Selected genes may be linked to other alleles, and inbreeding can expose harmful recessive alleles.
کارت ۴۶۶
پرسش
What data are needed to test Hardy–Weinberg genotype expectations?
پاسخ
Population genotype counts or reliable genotype frequencies for the locus.
کارت ۴۶۷
پرسش
Why doesn't one living species count as the ancestor of another on a typical tree?
پاسخ
Living tips represent lineages that have both evolved since their shared ancestral lineage.
کارت ۴۶۸
پرسش
Why can reduced gene flow accelerate divergence?
پاسخ
Populations retain separate mutations, drift independently, and respond to different selective pressures.
کارت ۴۶۹
پرسش
Why are ribozymes relevant to early-life hypotheses?
پاسخ
RNA can both store information and catalyze reactions, offering a possible bridge before modern DNA–protein systems.
کارت ۴۷۰
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What makes an evolutionary argument strong?
پاسخ
A clear claim, relevant population-level evidence, and reasoning that connects inheritance and differential reproduction to the observed change.
کارت ۴۷۱
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How can a directional response help an organism?
پاسخ
Moving toward resources or away from hazards can improve survival and reproduction.
کارت ۴۷۲
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What is a trophic level?
پاسخ
A feeding position in the flow of energy through an ecosystem.
کارت ۴۷۳
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What processes move carbon into and out of biological molecules?
پاسخ
Photosynthesis fixes carbon; respiration, decomposition, and combustion release carbon dioxide.
کارت ۴۷۴
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What does exponential population growth assume?
پاسخ
Resources are effectively unlimited and the per-capita growth rate stays constant.
کارت ۴۷۵
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What is a density-dependent limiting factor?
پاسخ
Its effect strengthens as population density rises, such as competition, disease, or predation.
کارت ۴۷۶
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What is a keystone species?
پاسخ
A species whose ecological effect is disproportionately large relative to its abundance.
کارت ۴۷۷
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What are three levels of biodiversity?
پاسخ
Genetic diversity, species diversity, and ecosystem diversity.
کارت ۴۷۸
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What is the independent variable in a fertilizer–algae experiment?
پاسخ
The fertilizer amount or nutrient concentration deliberately changed.
کارت ۴۷۹
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What shape represents exponential growth over time?
پاسخ
A J-shaped curve.
کارت ۴۸۰
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What do primary producers do?
پاسخ
They capture external energy and build organic molecules from inorganic carbon.
کارت ۴۸۱
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What is a density-independent limiting factor?
پاسخ
Its effect is not primarily set by population density, such as a severe freeze or wildfire.
کارت ۴۸۲
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Why is nitrogen fixation necessary?
پاسخ
Most organisms cannot use atmospheric nitrogen gas directly, so it must be converted to biologically available compounds.
کارت ۴۸۳
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What does logistic growth add to the exponential model?
پاسخ
Growth slows as population size approaches carrying capacity.
کارت ۴۸۴
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What is gross primary productivity?
پاسخ
The total rate at which producers capture energy in organic matter.
کارت ۴۸۵
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What is competition?
پاسخ
An interaction in which organisms using the same limited resource reduce one another's access or fitness.
کارت ۴۸۶
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What is ecological succession?
پاسخ
Change in community composition after new habitat forms or a disturbance alters an existing community.
کارت ۴۸۷
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What shape represents ideal logistic growth?
پاسخ
An S-shaped curve.
کارت ۴۸۸
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What is net primary productivity?
پاسخ
Gross primary productivity minus producers' respiratory energy use.
کارت ۴۸۹
پرسش
Why does genetic diversity matter for conservation?
پاسخ
It increases the range of inherited responses available under disease or environmental change.
کارت ۴۹۰
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What organisms perform much biological nitrogen fixation?
پاسخ
Certain prokaryotes, including free-living and symbiotic bacteria.
کارت ۴۹۱
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What is carrying capacity?
پاسخ
The population size an environment can sustain over time under current conditions.
کارت ۴۹۲
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Why is net primary productivity important to consumers?
پاسخ
It is the producer biomass and energy available for growth and the next trophic levels.
کارت ۴۹۳
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What is competitive exclusion?
پاسخ
Species with identical limiting-resource niches cannot coexist indefinitely under stable conditions.
کارت ۴۹۴
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How do primary and secondary succession differ?
پاسخ
Primary succession begins without developed soil; secondary succession begins where soil remains.
کارت ۴۹۵
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Why can carrying capacity change?
پاسخ
Resources, habitat, climate, competitors, disease, and disturbance can change.
کارت ۴۹۶
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Why does available energy decline up a food chain?
پاسخ
Organisms use much energy for metabolism and lose it as heat and waste rather than storing it as biomass.
کارت ۴۹۷
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What is an ecosystem service?
پاسخ
A benefit people receive from ecosystems, such as pollination, water purification, soil formation, or climate regulation.
کارت ۴۹۸
پرسش
What does nitrification do?
پاسخ
Microbes oxidize ammonium to nitrite and then nitrate.
کارت ۴۹۹
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What does per-capita growth rate measure?
پاسخ
Population change per individual per unit time.
کارت ۵۰۰
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What is ecological efficiency?
پاسخ
The percentage of energy or production transferred from one trophic level to the next.
کارت ۵۰۱
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What is resource partitioning?
پاسخ
Competing species use different resources, places, or times, reducing direct overlap.
کارت ۵۰۲
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What is resilience in an ecosystem?
پاسخ
The ability to recover structure or function after disturbance.
کارت ۵۰۳
پرسش
How is population growth estimated from births, deaths, immigration, and emigration?
پاسخ
Births + immigration − deaths − emigration.
کارت ۵۰۴
پرسش
If producers store 10,000 kJ and primary consumers receive 10%, how much do they receive?
پاسخ
1,000 kJ.
کارت ۵۰۵
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How does habitat fragmentation affect populations?
پاسخ
It shrinks and isolates habitat, reducing movement and gene flow while increasing edge effects.
کارت ۵۰۶
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Why sample several sites within each habitat?
پاسخ
Replication captures spatial variation and reduces the chance that one unusual site drives the result.
کارت ۵۰۷
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A population grows from 200 to 230 in one year. What is its percent growth?
پاسخ
15%, because the increase of 30 divided by 200 is 0.15.
کارت ۵۰۸
پرسش
What is a circadian rhythm?
پاسخ
An internal roughly 24-hour cycle that environmental cues can reset.
کارت ۵۰۹
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Why are food webs more realistic than simple food chains?
پاسخ
Most species eat or are eaten by multiple species, creating connected pathways.
کارت ۵۱۰
پرسش
What does denitrification do?
پاسخ
Microbes convert nitrate to nitrogen gases, returning nitrogen to the atmosphere.
کارت ۵۱۱
پرسش
What characterizes an r-selected life-history strategy?
پاسخ
Many offspring, early reproduction, and relatively low investment per offspring in variable environments.
کارت ۵۱۲
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What is mutualism?
پاسخ
An interaction that benefits both species.
کارت ۵۱۳
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What is resistance in an ecosystem?
پاسخ
The ability to remain relatively unchanged during disturbance.
کارت ۵۱۴
پرسش
How can climate change shift species ranges?
پاسخ
Organisms track suitable temperature, moisture, seasons, or interacting species when movement is possible.
کارت ۵۱۵
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What characterizes a K-selected life-history strategy?
پاسخ
Fewer offspring, later reproduction, and higher investment per offspring near carrying capacity.
کارت ۵۱۶
پرسش
A population curve levels near 800. What does the model suggest?
پاسخ
About 800 is the carrying capacity under those measured conditions, not a permanent universal value.
کارت ۵۱۷
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How can seasonal cues affect reproduction?
پاسخ
Changes such as day length can trigger hormonal and behavioral shifts timed to favorable conditions.
کارت ۵۱۸
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What role do decomposers play?
پاسخ
They break down dead material and waste, returning nutrients to forms other organisms can use.
کارت ۵۱۹
پرسش
Why can phosphorus limit ecosystems?
پاسخ
It is essential but often released slowly from rocks and lacks a large atmospheric gas phase.
کارت ۵۲۰
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What does a Type I survivorship curve show?
پاسخ
High survival through early and middle life, followed by a steep decline at older ages.
کارت ۵۲۱
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What is commensalism?
پاسخ
One species benefits while the other has no clear benefit or harm.
کارت ۵۲۲
پرسش
Why can diversity improve ecosystem stability?
پاسخ
Multiple species or response types can keep functions going when one component declines.
کارت ۵۲۳
پرسش
Why can overharvesting destabilize a population?
پاسخ
Removal faster than replacement lowers abundance and can alter age structure or genetic diversity.
کارت ۵۲۴
پرسش
Predator and prey peaks alternate over time. What can the graph establish?
پاسخ
Their abundances covary with a lag; the graph alone cannot prove the predator caused every prey change.
کارت ۵۲۵
پرسش
What is acclimation?
پاسخ
A reversible phenotypic adjustment by an individual to an environmental change.
کارت ۵۲۶
پرسش
Does energy cycle through an ecosystem?
پاسخ
No. Energy flows through and is ultimately dissipated as heat; matter cycles.
کارت ۵۲۷
پرسش
How does the water cycle connect ecosystems?
پاسخ
Evaporation, transpiration, condensation, precipitation, runoff, and infiltration move water and dissolved materials.
کارت ۵۲۸
پرسش
What does a Type II survivorship curve show?
پاسخ
A roughly constant mortality risk across ages.
کارت ۵۲۹
پرسش
What is parasitism?
پاسخ
A parasite benefits while reducing its host's fitness.
کارت ۵۳۰
پرسش
What is an invasive species?
پاسخ
A nonnative species that spreads and causes ecological, economic, or human-health harm.
کارت ۵۳۱
پرسش
How can a wildlife corridor help fragmented populations?
پاسخ
It supports movement, recolonization, and gene flow between habitat patches.
کارت ۵۳۲
پرسش
How should biodiversity be compared when sample effort differs?
پاسخ
Standardize sampling effort or use a method that accounts for unequal effort before comparing.
کارت ۵۳۳
پرسش
How does acclimation differ from adaptation?
پاسخ
Acclimation occurs within an individual; adaptation is an inherited population change across generations.
کارت ۵۳۴
پرسش
How can removal of a top predator affect lower trophic levels?
پاسخ
It can trigger a trophic cascade by changing prey abundance and the organisms prey consume.
کارت ۵۳۵
پرسش
Why can extra fertilizer cause low oxygen in water?
پاسخ
Nutrient enrichment drives algal growth; decomposition then consumes dissolved oxygen.
کارت ۵۳۶
پرسش
What does a Type III survivorship curve show?
پاسخ
High early mortality with much better survival among those reaching later stages.
کارت ۵۳۷
پرسش
How can predation maintain diversity?
پاسخ
A predator can prevent one strong competitor from dominating the community.
کارت ۵۳۸
پرسش
How can disturbance increase or decrease diversity?
پاسخ
Its effect depends on frequency and intensity; it may create habitat variety or eliminate sensitive species.
کارت ۵۳۹
پرسش
Why protect multiple habitats rather than one small reserve?
پاسخ
Different habitats, disturbances, and climate trajectories preserve more species and ecological options.
کارت ۵۴۰
پرسش
A restoration site gains species but not nutrient cycling. How should success be evaluated?
پاسخ
Use both composition and ecosystem-function measures; one metric alone gives an incomplete result.
۵۴۰ کارت
AP Biology Flashcards: Complete 8-Unit Course Review
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