BIO111 Final Exam Actual Exam V3 | BIO111 General Biology (BIO111
Final Exam) | UCLA
1. Which property of water allows it to move against gravity in the xylem of plants?
A. High specific heat
B. Versatility as a solvent
C. Expansion upon freezing
D. Cohesion and adhesion
Answer: D
Rationale: Cohesion refers to the hydrogen bonding between water molecules, while
adhesion is the attraction to cell walls. Together, these properties facilitate capillary action
within plant tissues. This mechanism is essential for the transport of water from roots to
leaves in tall trees.
2. Which level of protein structure is characterized by alpha-helices and beta-pleated sheets?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
Answer: B
Rationale: Secondary structure results from hydrogen bonds between the repeating
constituents of the polypeptide backbone. These interactions create specific localized
shapes like coils or folds. The primary structure is simply the sequence of amino acids,
whereas tertiary involves R-group interactions.
3. Which organelle is responsible for the synthesis of lipids and the detoxification of poisons?
A. Rough Endoplasmic Reticulum
B. Lysosome
C. Golgi Apparatus
D. Smooth Endoplasmic Reticulum
Answer: D
Rationale: The smooth ER lacks ribosomes and specializes in metabolic processes like lipid
synthesis. It also plays a critical role in metabolizing carbohydrates and detoxifying drugs
,or toxins. In contrast, the rough ER is primarily involved in protein synthesis and
modification.
4. What is the primary function of the sodium-potassium pump in animal cells?
A. To maintain an electrochemical gradient by pumping ions against their gradient
B. To move ions down their concentration gradient via facilitated diffusion
C. To synthesize ATP using a proton motive force
D. To transport glucose into the cell through osmosis
Answer: A
Rationale: The sodium-potassium pump is a form of active transport that uses ATP to
move ions. It pumps three sodium ions out for every two potassium ions it brings in. This
process is vital for maintaining the resting membrane potential in neurons and other cells.
5. Which of the following best describes the endosymbiont theory regarding mitochondria?
A. Mitochondria were once free-living aerobic prokaryotes that were engulfed by a host cell
B. Mitochondria evolved from the folding of the plasma membrane
C. Mitochondria formed from the nucleus breaking apart into smaller fragments
D. Mitochondria are non-living chemical complexes used for energy storage
Answer: A
Rationale: The endosymbiont theory suggests that mitochondria originated from an
ancestral prokaryote. Evidence includes their own circular DNA and double membrane
structure. This symbiotic relationship eventually led to the development of complex
eukaryotic life.
6. How do enzymes speed up chemical reactions in biological systems?
A. By increasing the total Gibbs free energy of the system
B. By lowering the activation energy barrier
C. By making the reaction endergonic rather than exergonic
D. By increasing the temperature of the reactants
Answer: B
Rationale: Enzymes act as catalysts by providing an alternative pathway for the reaction.
They stabilize the transition state, which reduces the energy required to initiate the
process. Importantly, enzymes do not change the delta G or equilibrium of the reaction.
7. During glycolysis, what is the net gain of ATP molecules per molecule of glucose?
A. 32 ATP
, B. 4 ATP
C. 2 ATP
D. 0 ATP
Answer: C
Rationale: Glycolysis consumes 2 ATP molecules in the energy investment phase. It then
produces 4 ATP molecules in the energy payoff phase via substrate-level phosphorylation.
Therefore, the net energy yield is 2 ATP and 2 NADH per glucose.
8. Where does the Citric Acid (Krebs) Cycle take place in a eukaryotic cell?
A. Mitochondrial matrix
B. Cytosol
C. Inner mitochondrial membrane
D. Intermembrane space
Answer: A
Rationale: The Citric Acid Cycle occurs within the matrix of the mitochondria. This cycle
completes the breakdown of glucose by oxidizing pyruvate derivatives to CO2. The electron
transport chain, however, is located on the inner membrane (cristae).
9. What is the final electron acceptor in the mitochondrial electron transport chain?
A. NAD+
B. Water
C. Carbon dioxide
D. Oxygen (O2)
Answer: D
Rationale: Oxygen acts as the final electron acceptor at the end of the electron transport
chain. It combines with electrons and protons to form water as a byproduct. Without
oxygen, the chain stops, and oxidative phosphorylation cannot occur.
10. In photosynthesis, where do the light reactions occur?
A. Stroma
B. Stomata
C. Outer membrane of the chloroplast
D. Thylakoid membranes
Answer: D
Final Exam) | UCLA
1. Which property of water allows it to move against gravity in the xylem of plants?
A. High specific heat
B. Versatility as a solvent
C. Expansion upon freezing
D. Cohesion and adhesion
Answer: D
Rationale: Cohesion refers to the hydrogen bonding between water molecules, while
adhesion is the attraction to cell walls. Together, these properties facilitate capillary action
within plant tissues. This mechanism is essential for the transport of water from roots to
leaves in tall trees.
2. Which level of protein structure is characterized by alpha-helices and beta-pleated sheets?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
Answer: B
Rationale: Secondary structure results from hydrogen bonds between the repeating
constituents of the polypeptide backbone. These interactions create specific localized
shapes like coils or folds. The primary structure is simply the sequence of amino acids,
whereas tertiary involves R-group interactions.
3. Which organelle is responsible for the synthesis of lipids and the detoxification of poisons?
A. Rough Endoplasmic Reticulum
B. Lysosome
C. Golgi Apparatus
D. Smooth Endoplasmic Reticulum
Answer: D
Rationale: The smooth ER lacks ribosomes and specializes in metabolic processes like lipid
synthesis. It also plays a critical role in metabolizing carbohydrates and detoxifying drugs
,or toxins. In contrast, the rough ER is primarily involved in protein synthesis and
modification.
4. What is the primary function of the sodium-potassium pump in animal cells?
A. To maintain an electrochemical gradient by pumping ions against their gradient
B. To move ions down their concentration gradient via facilitated diffusion
C. To synthesize ATP using a proton motive force
D. To transport glucose into the cell through osmosis
Answer: A
Rationale: The sodium-potassium pump is a form of active transport that uses ATP to
move ions. It pumps three sodium ions out for every two potassium ions it brings in. This
process is vital for maintaining the resting membrane potential in neurons and other cells.
5. Which of the following best describes the endosymbiont theory regarding mitochondria?
A. Mitochondria were once free-living aerobic prokaryotes that were engulfed by a host cell
B. Mitochondria evolved from the folding of the plasma membrane
C. Mitochondria formed from the nucleus breaking apart into smaller fragments
D. Mitochondria are non-living chemical complexes used for energy storage
Answer: A
Rationale: The endosymbiont theory suggests that mitochondria originated from an
ancestral prokaryote. Evidence includes their own circular DNA and double membrane
structure. This symbiotic relationship eventually led to the development of complex
eukaryotic life.
6. How do enzymes speed up chemical reactions in biological systems?
A. By increasing the total Gibbs free energy of the system
B. By lowering the activation energy barrier
C. By making the reaction endergonic rather than exergonic
D. By increasing the temperature of the reactants
Answer: B
Rationale: Enzymes act as catalysts by providing an alternative pathway for the reaction.
They stabilize the transition state, which reduces the energy required to initiate the
process. Importantly, enzymes do not change the delta G or equilibrium of the reaction.
7. During glycolysis, what is the net gain of ATP molecules per molecule of glucose?
A. 32 ATP
, B. 4 ATP
C. 2 ATP
D. 0 ATP
Answer: C
Rationale: Glycolysis consumes 2 ATP molecules in the energy investment phase. It then
produces 4 ATP molecules in the energy payoff phase via substrate-level phosphorylation.
Therefore, the net energy yield is 2 ATP and 2 NADH per glucose.
8. Where does the Citric Acid (Krebs) Cycle take place in a eukaryotic cell?
A. Mitochondrial matrix
B. Cytosol
C. Inner mitochondrial membrane
D. Intermembrane space
Answer: A
Rationale: The Citric Acid Cycle occurs within the matrix of the mitochondria. This cycle
completes the breakdown of glucose by oxidizing pyruvate derivatives to CO2. The electron
transport chain, however, is located on the inner membrane (cristae).
9. What is the final electron acceptor in the mitochondrial electron transport chain?
A. NAD+
B. Water
C. Carbon dioxide
D. Oxygen (O2)
Answer: D
Rationale: Oxygen acts as the final electron acceptor at the end of the electron transport
chain. It combines with electrons and protons to form water as a byproduct. Without
oxygen, the chain stops, and oxidative phosphorylation cannot occur.
10. In photosynthesis, where do the light reactions occur?
A. Stroma
B. Stomata
C. Outer membrane of the chloroplast
D. Thylakoid membranes
Answer: D
