Download 生物化學小考(一) 範圍ch1~ch4

生物化學小考(一)
範圍 ch1~ch4
單選題(每題 2 分, 總分 20 分)
1. To possess optical activity, a compound must be:
(A) a carbohydrate.
(B) a hexose.
(C) asymmetric.
(D) colored.
(E) D-glucose.
2. When two carbohydrates are epimers:
(A) one is a pyranose, the other a furanose.
(B) one is an aldose, the other a ketose.
(C) they differ in length by one carbon.
(D) they differ only in the configuration around one carbon atom.
(E) they rotate plane-polarized light in the same direction.
3. The basic structure of a proteoglycan consists of a core protein and a:
(A) glycolipid.
(B) glycosaminoglycan.
(C) lectin.
(D) lipopolysaccharide.
peptidoglycan.
(E)
4. Which of the following statements about starch and glycogen is false?
(A) Amylose is unbranched; amylopectin and glycogen contain many (α-1,6) branches.
(B) Both are homopolymers of glucose.
(C) Both serve primarily as structural elements in cell walls.
(D) Both starch and glycogen are stored intracellularly as insoluble granules.
(E) Glycogen is more extensively branched than starch.
5. 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 NAD+ and 4 mol of ATP.
(D) 2 mol of NADH and 2 mol of ATP.
(E) 2 mol of NADH and 4 mol of ATP.
6. If glucose labeled with 14C in C-1 were fed to yeast carrying out the ethanol fermentation, where
would the 14C label be in the products?
(A) In C-1 of ethanol and CO2
(B) In C-1 of ethanol only
(C) In C-2 (methyl group)
of ethanol only
(D) In C-2 of ethanol and CO2
(E) In CO2 only
7. Which of these cofactors participates directly in most of the oxidation-reduction reactions in the
fermentation of glucose to lactate?
(A) ADP
(B) ATP
(C) FAD/FADH2
(D) Glyceraldehyde 3-phosphate
(E)
NAD+/NADH
8. Which of the following statements is incorrect?
(A) Aerobically, oxidative decarboxylation of pyruvate forms acetate that enters the citric acid
cycle.
(B) In anaerobic muscle, pyruvate is converted to lactate.
(C) In yeast growing anaerobically, pyruvate is converted to ethanol.
(D) Reduction of pyruvate to lactate regenerates a cofactor essential for glycolysis.
(E)Under anaerobic conditions pyruvate does not form because glycolysis does not occur.
9. Which of the following compounds cannot serve as the starting material for the synthesis of
glucose via gluconeogenesis?
(A) acetate
(B) glycerol
(C) lactate
(D) oxaloacetate
(E) α-ketoglutarate
10. Which of the following is not true of the reaction catalyzed by the pyruvate dehydrogenase
complex?
(A) Biotin participates in the decarboxylation.
(B) Both NAD+ and a flavin nucleotide act as electron carriers.
(C) The reaction occurs in the mitochondrial matrix.
(D) The substrate is held by the lipoyl-lysine “swinging arm.”
(E) Two different cofactors containing —SH groups participate.
20-3
18-6
16-17
14-16
12-14
10-11
8-6
6-7
4-3
2-2
0-1