Bioc 385 Metabolic Biochemistry Final Exam Review Test Bank – 350 Latest Real Exam Questions With Correct Detailed Answers | University Of Arizona | Biochem 385 Final Exam

BIOC 385 METABOLIC
BIOCHEMISTRY FINAL EXAM
REVIEW TEST BANK – 350 LATEST
REAL EXAM QUESTIONS WITH
CORRECT DETAILED ANSWERS |
UNIVERSITY OF ARIZONA |
BIOCHEM 385 FINAL EXAM
SECTION 1: Bioenergetics & Enzyme Principles (1–40)
1. Which statement best defines the second law of thermodynamics?
A) Energy can be created but not destroyed.
B) Spontaneous processes in the universe tend toward dispersal of energy.
C) Enzymes lower the activation energy of a reaction.
D) ATP hydrolysis is always exergonic.
Answer: B. Rationale: The second law states that entropy (disorder) of the universe
increases; spontaneous processes disperse energy.

2. Enzymes increase the rate of biochemical reactions by:
A) Changing the equilibrium constant.
B) Lowering the activation energy barrier.
C) Increasing the free energy of the products.
D) Making ΔG more negative.
Answer: B. Rationale: Enzymes do not alter ΔG or equilibrium; they stabilize the
transition state, lowering activation energy.

3. What is the biochemical standard state pH?
A) 0
B) 7
C) 7.4
D) 14
Answer: B. Rationale: Biochemical standard state uses pH 7.0, whereas chemical
standard state uses pH 0 (1 M H⁺).

,4. For a reaction with a positive ΔG, which is true?
A) It is spontaneous.
B) It requires energy input.
C) The equilibrium constant is >1.
D) It cannot be coupled to ATP hydrolysis.
Answer: B. Rationale: Positive ΔG indicates a non-spontaneous (endergonic) reaction
that requires energy coupling.

5. The R state of an allosteric enzyme is:
A) The less active form.
B) The more active form.
C) Always bound to substrate.
D) Stabilized by negative regulators.
Answer: B. Rationale: R (relaxed) state has higher substrate affinity/activity; T (tense) is
less active.

6. If a negative allosteric regulator concentration increases, what happens to
the [R]/[T] ratio?
A) It increases.
B) It decreases.
C) It remains unchanged.
D) It oscillates.
Answer: B. Rationale: Negative regulators stabilize the T state, lowering the R/T ratio.

7. Which of the following is a biochemical property of enzyme active sites?
A) They are highly flexible and lack specificity.
B) They provide optimal orientation and exclude excess solvent.
C) They always contain metal ions.
D) They bind substrate covalently in all cases.
Answer: B. Rationale: Active sites orient substrates optimally and create a
microenvironment excluding bulk water.

8. Which two statements about enzyme active sites are correct?
A) They lower activation energy and change ΔG.
B) They provide optimal orientation and exclude excess solvent.
C) They are always located on the protein surface.
D) They are non-specific.
Answer: B. Rationale: Active sites orient substrates and exclude water; they do not alter
ΔG.

9. What are living organisms trying to avoid as long as possible?
A) ATP synthesis
B) Equilibrium with Earth
C) Enzyme denaturation

,D) Oxygen exposure
Answer: B. Rationale: Living systems maintain a steady state far from equilibrium;
equilibrium means death.

10. Which metabolic pathway do plants have that animals do not?
A) Glycolysis
B) Photosynthesis
C) Citrate cycle
D) β-oxidation
Answer: B. Rationale: Photosynthesis (light-driven carbon fixation) is absent in animals.

11. What organelle do both plants and animals have for NADH oxidation?
A) Chloroplast
B) Mitochondria
C) Peroxisome
D) Vacuole
Answer: B. Rationale: Mitochondria are the site of oxidative phosphorylation in both
plants and animals.

12. What metabolic pathway do both plants and animals use at night?
A) Photosynthesis
B) Aerobic respiration
C) Calvin cycle
D) Photorespiration
Answer: B. Rationale: Without light, both rely on aerobic respiration for ATP.

13. Eduard Buchner is considered the forefather of biochemistry because he
proved that:
A) DNA is the genetic material.
B) Enzymes are sufficient for alcoholic fermentation in the absence of live yeast,
provided glucose is supplied.
C) ATP is the energy currency.
D) Proteins are the product of translation.
Answer: B. Rationale: Buchner showed cell-free yeast extracts can ferment glucose,
establishing enzymology.

14. Which of the following is NOT a characteristic of carbohydrates?
A) Potential to form multiple hydrogen bonds
B) Existence of one or more asymmetric centers
C) Capacity to form polymers
D) Always containing a phosphate group
Answer: D. Rationale: Carbohydrates do not inherently contain phosphate;
phosphorylation is a modification.

, 15. The image below shows a(n) __________ glycosidic bond.
A) α(1→4)
B) β(1→4)
C) α(1→6)
D) β(1→6)
Answer: B. Rationale: β(1→4) linkages occur in cellulose; α(1→4) in starch/glycogen.

16. Which bond is formed during glycogen synthesis by glycogen synthase?
A) α(1→4)
B) α(1→6)
C) β(1→4)
D) β(1→6)
Answer: A. Rationale: Glycogen synthase adds glucose to the non-reducing end via
α(1→4) bonds.

17. Which enzyme catalyzes the formation of α(1→6) linkages during glycogen
synthesis?
A) Glycogen phosphorylase
B) Glycogen synthase
C) Branching enzyme
D) Debranching enzyme
Answer: C. Rationale: The branching enzyme creates α(1→6) branch points.

18. Which one of the following is involved in the breakdown of glycogen?
A) ATP
B) Inorganic phosphate
C) NADH
D) FADH₂
Answer: B. Rationale: Glycogen phosphorylase uses Pi to phosphorolyze glucose
residues, releasing glucose-1-P.

19. What would be the ATP cost per glucose residue if glycogen phosphorylase
and glycogen synthase simultaneously removed and added glucose to glycogen
ends?
A) 0 ATP
B) 1 ATP
C) 2 ATP
D) 3 ATP
Answer: B. Rationale: Synthase uses UTP (equivalent to 1 ATP); phosphorylase releases
glucose-1-P without ATP cost, but the net futile cycle costs 1 ATP.

20. How would you describe liver glycogen synthase after 24 hours without
food?
A) Fully active in the R state.