Biology Test Biology Biochemistry & Metabolism 1 — Questions and Answers
Question 1: Which molecule serves as the primary energy currency of the cell?
- ADP
- ATP (Correct answer)
- NADH
- GTP
Correct answer: ATP
ATP (adenosine triphosphate) stores and transfers chemical energy for cellular processes.
Question 2: Enzymes lower the activation energy of a reaction by:
- Increasing substrate concentration
- Providing an alternative reaction pathway (Correct answer)
- Raising the temperature
- Adding more reactants
Correct answer: Providing an alternative reaction pathway
Enzymes provide an alternative pathway with a lower activation energy, speeding up reactions without being consumed.
Question 3: Which process converts glucose into pyruvate in the cytoplasm?
- Krebs cycle
- Glycolysis (Correct answer)
- Oxidative phosphorylation
- Beta-oxidation
Correct answer: Glycolysis
Glycolysis is the cytoplasmic pathway that breaks down one glucose molecule into two pyruvate molecules, yielding 2 net ATP.
Question 4: What is the net ATP yield from one glucose molecule during glycolysis?
- 4 ATP
- 36 ATP
- 2 ATP (Correct answer)
- 38 ATP
Correct answer: 2 ATP
Glycolysis produces 4 ATP but uses 2 ATP as investment, giving a net yield of 2 ATP per glucose.
Question 5: Anabolic reactions in metabolism are characterized by:
- Breaking down large molecules
- Releasing energy
- Building complex molecules from simpler ones (Correct answer)
- Producing carbon dioxide
Correct answer: Building complex molecules from simpler ones
Anabolic reactions consume energy to synthesize complex macromolecules from smaller precursor molecules.
Question 6: Which coenzyme carries electrons from the Krebs cycle to the electron transport chain?
- FAD
- NAD+ (Correct answer)
- CoA
- ATP
Correct answer: NAD+
NAD+ is reduced to NADH in the Krebs cycle, then donates its electrons to Complex I of the electron transport chain.
Biology Test Biology Biochemistry & Metabolism 1
Which molecule serves as the primary energy currency of the cell?