114年 - [非官方正解]114 台灣綜合大學系統_學士班轉學生聯合招生考試：生物化學#129347

1. Which of the following is not true of the reaction producing malonyl-CoA during fatty acid synthesis? (A) It is stimulated by citrate. (B)It requires acyl carrier protein (ACP). (C) It requires CO2 (or bicarbonate). (D) One mole of ATP is converted to ADP + Pi for each malonyl-CoA synthesized. (E)The cofactor is biotin.

2. Which amino acid does not have a primary α-amino group?
(A) glutamine
(B)arginine
(C) lysine
(D) proline
(E)glutamate

3. Which amino acid residues are commonly found at the central positions of a β-turn?
(A) Alanine and Glycine
(B)Hydrophobic residues
(C) Proline and Glycine
(D) Residues with ionized R-groups
(E)Two cysteines

4. The conversion of 1 mol of fructose 1,6-bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of:
(A) 1 mol of NAD⁺ and 2 mol of ATP.
(B)1 mol of NADH and 1 mol of ATP.
(C) 2 mol of NADH and 4 mol of ATP.
(D) 2 mol of NADH and 2 mol of ATP.
(E)2 mol of NAD+ and 4 mol of ATP.

5. Which of the following substrates cannot contribute to net gluconeogenesis in mammalian liver?
(A) Lysine
(B)glutamate
(C) alanine
(D) pyruvate
(E)α-ketoglutarate

6. Of the 20 standard amino acids, only__________ is not optically active. The reason is that its side chain __________.
(A) alanine; is a simple methyl group
(B)glycine; is a hydrogen atom
(C) glycine; is unbranched
(D) lysine; contains only nitrogen
(E)proline; forms a covalent bond with the amino group

7. One amino acid directly involved in the purine biosynthetic pathway is:
(A) alanine.
(B)aspartate.
(C) glutamate.
(D) leucine.
(E) tryptophan

8. Which tripeptides carry a net positive charge at pH 7.0?
(A) Ala-Thr-Asn
(B)Gln-Val-Ser
(C) Arg-Glu-Met
(D) Pro-Ile-Leu
(E) Leu-Lys-Gly

9. All of the following are considered "weak" interactions in proteins, except:
(A) hydrogen bonds.
(B)hydrophobic interactions.
(C) ionic bonds.
(D) peptide bonds.
(E) van der Waals forces.

10. When oxygen binds to a heme-containing protein, the two open coordination bonds of Fe²⁺ are occupied by:
(A) one O atom and one amino acid atom.
(B)one O2 molecule and one amino acid atom.
(C) one O2 molecule and one heme atom.
(D) two O atoms.
(E) two O2 molecules.

11. Glucose labeled with ¹⁴C in C-1 and C-6 gives rise in glycolysis to pyruvate labeled in:
(A) A and C.
(B)all three carbons.
(C) its carbonyl carbon.
(D) its carboxyl carbon.
(E) its methyl carbon.

12. Which of the following molecules can inhibit glycogen phosphorylase a by binding to an allosteric site?
(A) AMP.
(B)calcium.
(C) GDP.
(D) glucagon.
(E) glucose.

13. Transamination from alanine to a-ketoglutarate requires the coenzyme:
(A) biotin.
(B)NADH.
(C) No coenzyme is involved.
(D) pyridoxal phosphate (PLP).
(E) thiamine pyrophosphate (TPP).

14. In an anaerobic muscle preparation, lactate formed from glucose labeled in C-3 and C-4 would be labeled in:
(A) all three carbon atoms.
(B)only the carbon atom carrying the OH.
(C) only the carboxyl carbon atom.
(D) only the methyl carbon atom.
(E) the methyl and carboxyl carbon atoms.

15. If electron transfer in tightly coupled mitochondria is blocked (with antimycin( A ) between cytochrome b and cytochrome cl, then:
(A) all ATP synthesis will stop.
(B)ATP synthesis will continue, but the P/O ratio will drop to one.
(C) electron transfer from NADH will cease, but O2 uptake will continue.
(D) electron transfer from succinate to O2 will continue unabated.
(E) energy diverted from the cytochromes will be used to make ATP, and the P/O ratio will rise.

16. If electron transfer in tightly coupled mitochondria is blocked (with antimycin( A ) between cytochrome b and cytochrome c1, then:
(A) all ATP synthesis will stop.
(B)ATP synthesis will continue, but the P/O ratio will drop to one.
(C) electron transfer from NADH will cease, but O2 uptake will continue.
(D) electron transfer from succinate to O2 will continue unabated.
(E) energy diverted from the cytochromes will be used to make ATP, and the P/O ratio will rise.

17. If a person's urine contains unusually high concentrations of urea, which one of the following diets has he or she probably been eating recently?
(A) High carbohydrate, very low protein
(B)Very high carbohydrate, no protein, no fat
(C) Very very high fat, high carbohydrate, no protein
(D) Very high fat, very low protein
(E) Very low carbohydrate, very high protein

18. Which of the below is not required for the oxidative decarboxylation of pyruvate to form acetyl-CoA?
(A) ATP
(B)CoA-SH
(C) FAD
(D) Lipoic acid
(E) NAD+

19. Which of the following statements about a plot of Vo vs. [S] for an enzyme that follows Michaelis-Menten kinetics is false?
(A) As [S] increases, the initial velocity of reaction Vo also increases.
(B)At very high [S], the velocity curve becomes a horizontal line that intersects the y-axis at Km.
(C) Km is the [S] at which V₀ = 1/2 Vmax.
(D) The shape of the curve is a hyperbola.
(E) The y-axis is a rate term with units of µm/min.

20. Glutamine, arginine, and proline:
(A) do not have a common precursor.
(B)may all be derived from a citric acid cycle intermediate.
(C) may all be derived from a Cori cycle intermediate.
(D) may all be derived from a glycolytic intermediate.
(E) may all be derived from a urea cycle intermediate.

B. Assay Questions (50%):
1. Give two reactions that require the cofactor of vitamin B12 or its derivative in mammalian metabolism. (6%)

(a) glycerol (1%)

(b) fructose in liver (1%)

(c) mannose (1%)

(d) galactose (1%)

(e) fructose-6-phosphate (1%)

(f) 1,3-bisphosphoglycerate (1%)

3. How does binding of epinephrine to β-adrenergic receptor initiate the cAMP production? (5%)

4. What are receptor tyrosine kinases? (2%) Give an example. (2%)

5. Insulin signaling can block the activity of GSK-3. Give the detailed molecular pathway for this signal transduction. (5%)

6. Describe the pathway for fatty acids that are activated and transported into mitochondria for β-oxidation. (5%)

(a) Cyanide (1%)

(b) antimycin A (1%)

(c) rotenone (1%)

(d) bongkrekic acid (1%)

8. Epinephrine acts on muscles, activates the activity of cAMP-dependent protein kinase and stimulates glycolysis. However, epinephrine acts on the liver and also activates the activity of CAMP-dependent protein kinase, but blocks glycolysis. Why? (5%)

9. Hypercholesterolemic individuals taking statins are sometimes advised to take supplements of coenzyme Q. Why? (5%)

10. A globular protein aggregates to form either a tetrahedral tetramer or a linear tetramer. If a mixture is chromatographed with a Sephadex gel, which form will elute first? (2%) Why? (3%)