AP BIOLOGY –QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A |
INSTANT DOWNLOAD PDF.
*Core Domains*
*1. Chemistry of Life*
*2. Cell Structure and Function*
*3. Cellular Energetics*
*4. Cell Communication and Cell Cycle*
*5. Heredity*
*6. Gene Expression and Regulation*
*7. Natural Selection*
*8. Ecology*
*Introduction*
*The purpose of this examination is to evaluate mastery of advanced biological concepts and the capacity to sy
Section One: Questions 1–100
1. Which functional group found in amino acids is primarily responsible for the formation of disulfide bridges in
protein tertiary structure?
A. Carboxyl group
B. Amino group
🟢 C. Sulfhydryl group
D. Methyl group
🔴 RATIONALE: The sulfhydryl (-SH) group of the amino acid cysteine is capable of forming covalent disulfide
bonds with another cysteine residue, which stabilizes the tertiary structure of proteins.
,2. During cellular respiration, which process occurs in the cytosol of eukaryotic cells?
🟢 A. Glycolysis
B. Citric acid cycle
C. Oxidative phosphorylation
D. Electron transport chain
🔴 RATIONALE: Glycolysis is an anaerobic process that takes place in the cytoplasm, whereas the other
processes listed occur within the mitochondria.
3. If a DNA sample contains 20% adenine, what is the expected percentage of guanine?
A. 20%
B. 30%
C. 40%
🟢 D. 30%
🔴 RATIONALE: According to Chargaff's rules, A=T and C=G. If A=20%, then T=20%. This leaves 60% for C and
G combined, meaning G must be 30%.
4. Which of the following is a characteristic of facilitated diffusion?
A. It requires ATP.
B. It moves substances against their concentration gradient.
🟢 C. It utilizes specific membrane proteins to transport molecules.
D. It only transports nonpolar molecules.
🔴 RATIONALE: Facilitated diffusion is a type of passive transport that uses transport proteins to move polar or
charged molecules down their concentration gradient without requiring energy.
5. What is the primary role of the Golgi apparatus in a cell?
A. Synthesis of proteins
🟢 B. Modification, sorting, and packaging of proteins
C. Production of ATP
D. Degradation of macromolecules
🔴 RATIONALE: The Golgi apparatus acts as the shipping and receiving center, where proteins from the
endoplasmic reticulum are modified, stored, and sent to their final destinations.
, 6. In the context of enzyme kinetics, what effect does a competitive inhibitor have?
🟢 A. It increases the Km value.
B. It decreases the Vmax value.
C. It binds to an allosteric site.
D. It irreversibly denatures the enzyme.
🔴 RATIONALE: Competitive inhibitors bind to the active site, competing with the substrate and thus requiring a
higher substrate concentration to reach half-maximum velocity, which is represented by an increased Km .
7. Which evolutionary mechanism is primarily responsible for introducing new genetic variations into a population?
A. Natural selection
B. Genetic drift
🟢 C. Mutation
D. Gene flow
🔴 RATIONALE: Mutations create new alleles, which are the raw material upon which natural selection and other
evolutionary forces act.
8. A cell is placed in a hypertonic solution. What will happen to the cell?
A. It will gain water and swell.
B. It will remain unchanged.
🟢 C. It will lose water and shrivel.
D. It will undergo lysis.
🔴 RATIONALE: In a hypertonic solution, the solute concentration is higher outside the cell, causing water to flow
out of the cell via osmosis.
9. What is the final electron acceptor in the electron transport chain of aerobic respiration?
A. N AD +
🟢 B. Oxygen
C. F AD
D. Water
🔴 RATIONALE: Oxygen is the final electron acceptor at the end of the electron transport chain, where it
combines with electrons and hydrogen ions to form water.
INSTANT DOWNLOAD PDF.
*Core Domains*
*1. Chemistry of Life*
*2. Cell Structure and Function*
*3. Cellular Energetics*
*4. Cell Communication and Cell Cycle*
*5. Heredity*
*6. Gene Expression and Regulation*
*7. Natural Selection*
*8. Ecology*
*Introduction*
*The purpose of this examination is to evaluate mastery of advanced biological concepts and the capacity to sy
Section One: Questions 1–100
1. Which functional group found in amino acids is primarily responsible for the formation of disulfide bridges in
protein tertiary structure?
A. Carboxyl group
B. Amino group
🟢 C. Sulfhydryl group
D. Methyl group
🔴 RATIONALE: The sulfhydryl (-SH) group of the amino acid cysteine is capable of forming covalent disulfide
bonds with another cysteine residue, which stabilizes the tertiary structure of proteins.
,2. During cellular respiration, which process occurs in the cytosol of eukaryotic cells?
🟢 A. Glycolysis
B. Citric acid cycle
C. Oxidative phosphorylation
D. Electron transport chain
🔴 RATIONALE: Glycolysis is an anaerobic process that takes place in the cytoplasm, whereas the other
processes listed occur within the mitochondria.
3. If a DNA sample contains 20% adenine, what is the expected percentage of guanine?
A. 20%
B. 30%
C. 40%
🟢 D. 30%
🔴 RATIONALE: According to Chargaff's rules, A=T and C=G. If A=20%, then T=20%. This leaves 60% for C and
G combined, meaning G must be 30%.
4. Which of the following is a characteristic of facilitated diffusion?
A. It requires ATP.
B. It moves substances against their concentration gradient.
🟢 C. It utilizes specific membrane proteins to transport molecules.
D. It only transports nonpolar molecules.
🔴 RATIONALE: Facilitated diffusion is a type of passive transport that uses transport proteins to move polar or
charged molecules down their concentration gradient without requiring energy.
5. What is the primary role of the Golgi apparatus in a cell?
A. Synthesis of proteins
🟢 B. Modification, sorting, and packaging of proteins
C. Production of ATP
D. Degradation of macromolecules
🔴 RATIONALE: The Golgi apparatus acts as the shipping and receiving center, where proteins from the
endoplasmic reticulum are modified, stored, and sent to their final destinations.
, 6. In the context of enzyme kinetics, what effect does a competitive inhibitor have?
🟢 A. It increases the Km value.
B. It decreases the Vmax value.
C. It binds to an allosteric site.
D. It irreversibly denatures the enzyme.
🔴 RATIONALE: Competitive inhibitors bind to the active site, competing with the substrate and thus requiring a
higher substrate concentration to reach half-maximum velocity, which is represented by an increased Km .
7. Which evolutionary mechanism is primarily responsible for introducing new genetic variations into a population?
A. Natural selection
B. Genetic drift
🟢 C. Mutation
D. Gene flow
🔴 RATIONALE: Mutations create new alleles, which are the raw material upon which natural selection and other
evolutionary forces act.
8. A cell is placed in a hypertonic solution. What will happen to the cell?
A. It will gain water and swell.
B. It will remain unchanged.
🟢 C. It will lose water and shrivel.
D. It will undergo lysis.
🔴 RATIONALE: In a hypertonic solution, the solute concentration is higher outside the cell, causing water to flow
out of the cell via osmosis.
9. What is the final electron acceptor in the electron transport chain of aerobic respiration?
A. N AD +
🟢 B. Oxygen
C. F AD
D. Water
🔴 RATIONALE: Oxygen is the final electron acceptor at the end of the electron transport chain, where it
combines with electrons and hydrogen ions to form water.
