113年 - [無官方正解]113 國立中正大學_碩士班招生考試試題_生物醫學科學系：生物化學#136966

1. Inside our cells, free nucleotides are almost always associated with______.
(A)proteins
(B)cholesterol
(C)CI counterions(D)fatty acids(E) Mg²⁺ counterions

2. Nucleotides in a DNA molecule are linked together through
(A)glycosidic bonds.
(B)amide linkages.
(C)hydrogen bonds.
(D)phosphoanhydride bonds.
(E) phosphodiester bonds.

3. It is impossible for RNA to store genetic information, because
(A)RNA does not base pair and therefore cannot be replicated.
(B)enzymes cannot process genetic information in the form of RNA.
(C)RNA forms complex folded structures.
(D)RNA is very unstable.
(E) None ofthe above answers is correct; RNA can store genetic information.

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

5. Zwitterions are
(A)amino acids.
(B)ionic molecules that are racemic.
(C)ions that bear both negatively and positively charged groups.
(D)side chain carboxylate anions.
(E) delocalized ions.

6. Which of the following amino acids has a charged polar side chain at pH 7.0?
(A)Leu
(B)Ala
(C)Met
(D)Trp
(E) Glu

7.The isoelectronic point of an amino acid is the point where (A)the pKa of the a-carboxylic acid is the same as the pK, of the a-amino group. (B)the a-carboxylic acid is protonated and the a-amino group is unprotonated. (C)the solubility of the amino acid is maximized. (D)the a-carboxylic acid and the a-amino group are both half protonated.(E)the amino acid carries no net electrical charge.

8. Which of the following amino acids does not have an ionizable side chain? (A)Asp (B)Cys (C)Lys (D)His (E) Asn

9.While proteins are usually composed of linear chains of amino acids, branched chains of amino acids and internally cross-linked chains can be found in certain proteins. Polypeptide chains are most commonly linked to each other through (A)hydrogen bonds. (B)glycosidic bonds. (C)peptide bonds. (D)disulfide bonds. (E) ester linkages.

10. Which gas does not bind to the porphyrin ring Fe(II) ion in myoglobin?
(A)NO
(B)CO
(C)CO₂
(D)O₂
(E) H₂S

11. Myoglobin's secondary structure is primarily composed of________.
(A)parallel B-sheets
(B)antiparallel B-sheets
(C)a-helices
(D)2-loops
(E) polyproline helices

12. Myoglobin and a single chain of hemoglobin have similar________ structures.
(A)primary(B)secondary
(C)tertiary
(D)quaternary
(E) none of the above

13. Which of the following monosaccharides is not an aldose?
(A)erythrose
(B)fructose
(C)glucose
(D)glyceraldehyde
(E) ribose

14. When the linear form of glucose cyclizes, the product is a(n):
(A)anhydride.
(B)glycoside.
(C)hemiacetal.
(D)lactone.
(E) oligosaccharide.

15. In a double-stranded nucleic acid, cytosine typically base-pairs with:
(A)adenosine.
(B)guanine.
(C)inosine.
(D)thymine.
(E) uracil.

16.Compounds that generate nitrous acid (such as nitrites, nitrates, and nitrosamines) change DNA molecules by:
(A)breakage of phosphodiester bonds.
(B)deamination of bases.
(C)depurination.
(D)formation of thymine dimers.
(E) transformation of A→T.

17. Peripheral membrane proteins:
(A)are generally noncovalently bound to membrane lipids.
(B)are usually denatured when released from membranes.
(C)can be released from membranes only by treatment with detergent(s).
(D)may have functional units on both sides of the membrane.
(E) penetrate deeply into the lipid bilayer.

18.The anaerobic conversion of 1 mol of glucose to 2 mol of lactate by fermentation is accompanied by a
net gain of:
(A)1 mol of ATP.
(B)1 mol of NADH.
(C)2 mol of ATP.
(D)2 mol of NADH.
(E) none of the above.

19. Glycolysis in the erythrocyte produces pyruvate that is further metabolized to:
(A)CO2.
(B)ethanol.
(C)glucose.
(D)hemoglobin.
(E) lactate.

20. Which of the following is a cofactor in the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase?
(A)ATP
(B)Cu²⁺
(C)heme
(D)NAD⁺
(E) NADР⁺

21. Which of the following statements about the pentose phosphate pathway is correct?
(A)It generates 36 mol of ATP per mole of glucose consumed.
(B)It generates 6 moles of CO2 for each mole of glucose consumed
(C)It is a reductive pathway; it consumes NADH.
(D)It is present in plants, but not in animals.
(E) It provides precursors for the synthesis of nucleotides.

22. The glycogen-branching enzyme catalyzes:
(A)degradation of (a1→4) linkages in glycogen
(B)formation of (a1→ 4) linkages in glycogen.
(C)formation of (a1→ 6) linkages during glycogen synthesis.
(D)glycogen degradation in tree branches.
(E) removal of unneeded glucose residues at the ends of branches.

23. Gluconeogenesis must use "bypass reactions" to circumvent three reactions in the glycolytic pathway that are highly exergonic and essentially irreversible. Reactions carried out by which three of the enzymes listed must be bypassed in the gluconeogenic pathway?
1) Hexokinase
2) Phosphoglycerate kinase
3) Phosphofructokinase-1
4) Pyruvate kinase
5) Triosephosphate isomerase(A)1,2,3(B)1, 2,4(C)1,4,5(D)1,3,4(E) 2, 3, 4

24. Which of the following is not an intermediate of the citric acid cycle?
(A)Acetyl-coA
(B)Citrate
(C)Oxaloacetate
(D)Succinyl-coA
(E) a-Ketoglutarate

25. Transport of fatty acids from the cytoplasm to the mitochondrial matrix requires:
(A)ATP, carnitine, and coenzyme A.
(B)ATP, carnitine, and pyruvate dehydrogenase.
(C)ATP, coenzyme A, and hexokinase.
(D)ATP, coenzyme A, and pyruvate dehydrogenase.
(E) carnitine, coenzyme A, and hexokinase.

1. Give two reactions that carry out the substrate-level phosphorylation in glycolysis. (4%)

(a) glyceraldehyde-3-phosphate (2%)

(b) fructose in the liver (2%) (c) glucose (2%)

3. List five coenzymes that are required for the oxidative decarboxylation of alpha-ketoglutarate. (5%)

4. Fluoroacetate is toxic to most of the animals. Why? (2%) Which compound in citric acid cycle will accumulate in cells after treatment with fluoroacetate? (2%)

5. Ketone bodies will be built up in the severe diabetes mellitus patients. Why? (5%)

6. If malonyl-CoA is synthesized from ¹⁴CO₂ and unlabeled acetyl-CoA, and the labeled malonate is then used for fatty acid synthesis, which carbon in the final product, palmitate, will be labeled with radioisotope? (5%)

7. During starvation, more urea production occurs. Why? (5%)

8. Describe five possible metabolic fates for glucose 6-phosphate in the liver. (5%)

9. Describe the roles of glutamine synthetase, glutamate dehydrogenase and glutaminase in the metabolism of amino groups in mammals. (6%)

10. What are GOT and GPT? (2%) Why can GOT and GPT be used as an indicator for tissue damages.(3%)