Bio 180 Exam 4 Practice Questions and
Answers (BYUI)
Enzyme Activity
Q: What happens to enzyme activity if the pH shifts drastically from its optimum?
A: Activity decreases.
Rationale: Enzyme structure is altered, disrupting the active site.
ATP Hydrolysis
Q: Hydrolysis of ATP releases energy because…
A: The terminal phosphate bond is unstable and high-energy.
Rationale: Breaking this bond yields ADP + Pi and free energy.
Oxidation
Q: Oxidation is defined as…
A: Loss of electrons.
Rationale: Paired with reduction in redox reactions.
Reduction
Q: Reduction is defined as…
A: Gain of electrons.
Rationale: Essential for NAD+ → NADH conversion.
NADH Role
Q: NADH functions primarily as…
A: An electron carrier.
Rationale: Transfers electrons to the electron transport chain.
Glycolysis Location
Q: Glycolysis occurs in the…
A: Cytoplasm.
Rationale: Independent of organelles, anaerobic.
Krebs Cycle Location
Q: Krebs cycle occurs in the…
A: Mitochondrial matrix.
Rationale: Enzymes for cycle are located there.
Electron Transport Chain
Q: The electron transport chain is located in the…
A: Inner mitochondrial membrane.
Rationale: Houses protein complexes for proton pumping.
Chemiosmosis
Q: ATP synthase uses what to produce ATP?
, A: Proton gradient.
Rationale: Protons flow down gradient, driving ATP formation.
Substrate-level Phosphorylation
Q: Occurs during which stages?
A: Glycolysis and Krebs cycle.
Rationale: Direct transfer of phosphate to ADP.
Oxidative Phosphorylation
Q: Requires what final electron acceptor?
A: Oxygen.
Rationale: Oxygen forms water with electrons and protons.
Fermentation
Q: Purpose of fermentation?
A: Regenerate NAD+.
Rationale: Allows glycolysis to continue without oxygen.
Lactic Acid Fermentation
Q: End product is…
A: Lactate.
Rationale: Occurs in muscle cells under anaerobic conditions.
Alcohol Fermentation
Q: End products are…
A: Ethanol and CO₂.
Rationale: Common in yeast.
Allosteric Regulation
Q: Enzyme activity is controlled by…
A: Binding at a site other than the active site.
Rationale: Alters enzyme conformation.
Feedback Inhibition
Q: Occurs when…
A: End product inhibits an earlier enzyme.
Rationale: Prevents overproduction.
Pyruvate
Q: Pyruvate is converted to…
A: Acetyl-CoA.
Rationale: Entry point into Krebs cycle.
ATP Yield
Q: Approximate ATP yield per glucose in aerobic respiration?
A: ~30–32 ATP.
Answers (BYUI)
Enzyme Activity
Q: What happens to enzyme activity if the pH shifts drastically from its optimum?
A: Activity decreases.
Rationale: Enzyme structure is altered, disrupting the active site.
ATP Hydrolysis
Q: Hydrolysis of ATP releases energy because…
A: The terminal phosphate bond is unstable and high-energy.
Rationale: Breaking this bond yields ADP + Pi and free energy.
Oxidation
Q: Oxidation is defined as…
A: Loss of electrons.
Rationale: Paired with reduction in redox reactions.
Reduction
Q: Reduction is defined as…
A: Gain of electrons.
Rationale: Essential for NAD+ → NADH conversion.
NADH Role
Q: NADH functions primarily as…
A: An electron carrier.
Rationale: Transfers electrons to the electron transport chain.
Glycolysis Location
Q: Glycolysis occurs in the…
A: Cytoplasm.
Rationale: Independent of organelles, anaerobic.
Krebs Cycle Location
Q: Krebs cycle occurs in the…
A: Mitochondrial matrix.
Rationale: Enzymes for cycle are located there.
Electron Transport Chain
Q: The electron transport chain is located in the…
A: Inner mitochondrial membrane.
Rationale: Houses protein complexes for proton pumping.
Chemiosmosis
Q: ATP synthase uses what to produce ATP?
, A: Proton gradient.
Rationale: Protons flow down gradient, driving ATP formation.
Substrate-level Phosphorylation
Q: Occurs during which stages?
A: Glycolysis and Krebs cycle.
Rationale: Direct transfer of phosphate to ADP.
Oxidative Phosphorylation
Q: Requires what final electron acceptor?
A: Oxygen.
Rationale: Oxygen forms water with electrons and protons.
Fermentation
Q: Purpose of fermentation?
A: Regenerate NAD+.
Rationale: Allows glycolysis to continue without oxygen.
Lactic Acid Fermentation
Q: End product is…
A: Lactate.
Rationale: Occurs in muscle cells under anaerobic conditions.
Alcohol Fermentation
Q: End products are…
A: Ethanol and CO₂.
Rationale: Common in yeast.
Allosteric Regulation
Q: Enzyme activity is controlled by…
A: Binding at a site other than the active site.
Rationale: Alters enzyme conformation.
Feedback Inhibition
Q: Occurs when…
A: End product inhibits an earlier enzyme.
Rationale: Prevents overproduction.
Pyruvate
Q: Pyruvate is converted to…
A: Acetyl-CoA.
Rationale: Entry point into Krebs cycle.
ATP Yield
Q: Approximate ATP yield per glucose in aerobic respiration?
A: ~30–32 ATP.
