Why is a water molecule polar?

Oxygen pulls shared electrons more strongly than hydrogen, giving oxygen a partial negative charge and the hydrogens partial positive charges.

Which elements make up most biological molecules?

Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur—often shortened to CHNOPS.

What is the relationship between a monomer and a polymer?

Monomers are small building blocks; polymers are chains or networks made from repeated monomers.

What is a monosaccharide's main role in cells?

It can provide quick energy and serve as a building block for larger carbohydrates.

Why do lipids mix poorly with water?

Most of their bonds are nonpolar, so water cannot form favorable interactions with them.

What three parts make up a nucleotide?

A five-carbon sugar, a phosphate group, and a nitrogenous base.

What parts of an amino acid vary and stay constant?

The amino group, carboxyl group, hydrogen, and central carbon are shared; the side chain, or R group, varies.

What does pH measure?

The negative logarithm of hydrogen-ion concentration; lower pH means more hydrogen ions.

What is a hydrogen bond in liquid water?

A weak attraction between a partially positive hydrogen on one water molecule and a partially negative oxygen on another.

How does an unsaturated fatty acid differ from a saturated one?

An unsaturated fatty acid has at least one carbon–carbon double bond; a saturated fatty acid has none.

What does dehydration synthesis do?

It joins subunits with a covalent bond while removing the elements of water.

How does cohesion help water move through a plant?

Hydrogen bonds keep water molecules linked, helping a continuous column rise through xylem.

How do plants and animals differ in short-term glucose storage?

Plants store glucose mainly as starch; animals store it mainly as glycogen.

How does a cis double bond affect a fatty-acid tail?

It introduces a bend that prevents neighboring tails from packing tightly.

How does adhesion support water transport in narrow tubes?

Water sticks to polar surfaces, helping it resist gravity along cell walls.

Which base pairing distinguishes RNA from DNA?

RNA uses uracil, so adenine pairs with uracil instead of thymine.

What stabilizes common protein secondary structures?

Hydrogen bonds between atoms in the polypeptide backbone.

Why can carbon form so many biological structures?

It has four valence electrons and can form four stable covalent bonds, including chains, branches, and rings.

Why can some insects stand on water?

Cohesion among surface water molecules creates high surface tension.

What does hydrolysis do to a biological polymer?

It adds the elements of water to break a covalent bond between subunits.

Why are fats useful for long-term energy storage?

Their many C–H bonds store substantial chemical energy, and hydrophobic storage adds little water mass.

How does water buffer rapid temperature change?

Breaking and forming many hydrogen bonds absorbs or releases substantial heat, giving water a high specific heat.

What does antiparallel mean for a DNA double helix?

Its two strands run in opposite directions: one 5′→3′ and the other 3′→5′.

What mainly drives a protein's tertiary structure?

Interactions among side chains, including hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.

What is a trace element?

An element an organism needs in very small amounts, such as iron in many electron-transfer proteins.

Why does sweating cool an organism?

The fastest water molecules escape as vapor, carrying heat away from the surface.

A cell builds a polysaccharide from sugars. Is water consumed or released?

Released. Forming each linkage by dehydration removes water.

Why can branching help a storage polysaccharide release glucose quickly?

More branch ends give enzymes more sites to work at once.

What makes a phospholipid amphipathic?

It has a polar, hydrophilic head and nonpolar, hydrophobic tails.

Where is biological information encoded in a nucleic acid?

In the linear sequence of nucleotide bases.

What is quaternary protein structure?

The arrangement of two or more polypeptide subunits into one functional protein.

Why does ice float on liquid water?

Stable hydrogen bonds hold ice molecules in an open lattice, making ice less dense than liquid water.

How does electronegativity affect a covalent bond?

A difference in attraction for electrons makes electron sharing unequal and can create a polar bond.

Why do phospholipids form bilayers in water?

Hydrophilic heads face water while hydrophobic tails cluster away from it.

To which end are nucleotides added during nucleic-acid synthesis?

The 3′ end of the growing strand.

Why can one amino-acid substitution change protein function?

It can alter side-chain interactions, folding, stability, or an active or binding site.

How does a buffer resist a pH change?

It can accept added hydrogen ions or donate them when hydrogen-ion concentration falls.

Why is water a useful solvent for cells?

Its partial charges surround ions and other polar molecules, separating and dispersing them.

Why do functional groups matter in organic molecules?

They give carbon skeletons predictable chemical properties, such as polarity, acidity, or reactivity.

Why can two polymers built from similar monomers have different functions?

Their monomer sequence, branching, length, and three-dimensional shape can differ.

A seedling consumes stored starch. What happens to the starch?

Hydrolysis breaks it into smaller sugars that can enter energy pathways.

What are two biological roles of steroids?

Some act as signaling molecules, and cholesterol helps stabilize animal cell membranes.

What bond forms the backbone of a nucleic-acid strand?

Covalent phosphodiester bonds link the sugar of one nucleotide to the phosphate of the next.

What does denaturation do to a protein?

It disrupts the protein's three-dimensional shape and often its function without usually breaking the primary peptide chain.

An enzyme works best near pH 7 but slows at pH 3. What is a likely explanation?

Extra hydrogen ions changed charges and interactions that maintain the enzyme's active shape.

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.

Tác giả Open Study Contributor

Về bộ thẻ này

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

Thẻ trong bộ này

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

A colorful biology collage links a cell, DNA helix, energy pathways, inherited variation, and an ecosystem.

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AP Biology Flashcards: Complete 8-Unit Course Review

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AP Biology Flashcards: Complete 8-Unit Course Review

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