学年第 学期
级临床医学专业生物化学试题（A卷）标准答案
一．名词解释
1．The grouping of secondary structural elements that fold to near each other in space and have special functions, such as αα motif, β α β motif, zinc finger motif. Some motifs consist of only a few conserved functionally important AAs rather than super-secondary structures. e.g. RGD (Arg-Gly-Asp ) motif
2．Triacylglycerols stored in adipose tissue are hydrolyzed; the products glycerol and fatty acid are transported to tissues; fatty acids can be oxidized for energy production; the principal enzyme in mobilizing stored fat is triacylglycerol lipase, which is hormone-sensitive.
3．The process of the enzymatic phosphorylation of ADP to ATP coupled to electron transfer from a substrate to molecular oxygen is termed Oxidative phosporylation.
4．After the absorption of most of protein, intestinal bacterial activity act on the residue passed into the large intestine, that is called putrefaction of protein.Most of the producer of the putrefaction of protein are harmful to human beings, for example: amine, ammonia, phenol, indole and sulfureted hydrogen.
5．Some non-nutrient substances can be converted to more polar metabolites by various chemical reactions such as oxidation, reduction, hydrolyzation, and conjugation, which are then excreted from the body. These processes mainly occur in liver.
二．选择题
A型题：
1．B;
2．B
3．D
4．D
5．B
6．C
7．C
8．D
9．C
10．B
11．B
12．B
13．D
14．A
15．D
16．E
17．C
18．B
19．A
20．A
X型题：
21．ABD
22．ABC
23．ABCDE
24．CDE
25．BDE
26．BDE
27．ABCE
28．BCDE
29．ABD
30．ACDE
31．ABCD
32．ABDE
33．ACD
34．ABCE
35．ABC
36．BC
37．BC
38．BD
39．BDE
40．ACD
三. 问答题
1．Both to the positive pole，and the velocity of HbA is quicker。
Proteins are amphoteric molecules, contain dissociating groups of opposite charge, -COOH, -NH2 at end terminus and side chains. the net charge of these molecules in solution depends on the pH. pI is the pH at which protein molecular becomes electrically neutral, has no net electric charge.When pH of buffer ＞ pI, the protein is taking the negative charge. Since the pI of HbA is more far from the pH of buffer, it has more net charge.
2．Some enzymes are synthesized and secreted as large inactive precursors called zymogens or proenzymes. Zymogens are activated by the irreversible hydrolysis one or more peptide bonds and forming or exposing the active site in the enzyme molecule.
Significance：
（1）protect organs
（2）confirm that the enzyme works at the right position
（3）as the storing form
3．（1）the metabolism products acetyl CoA, NADPH and ATP can be used to synthesize fatty acids
（2）the middle product can be transformed to 3-P-glycerin
(3) Citric acid, isocitric and ATP can activate acetyl CoA carboxylase
（4）the content of insulin in blood increases, so the HSL is inhibited and also themobilization of triacylglycerol. At the same time, the synthesis of fatty acids is induced
4. Glycolysis; lactic acid; TAC; amino acids; ketone bodies; oxaloacetate
5．Liver: take up billirubin →conjugated billirubin (GA- billirubin) →excrete in bile
blood：conjugated billirubin increase a lot;
urine：urobilirubin increase, urobilinogen and urobilin decrease;
feces：bilinogen and bilin decrease
There is some problem for biliary excretion. Conjugated billirubin has to go back to blood. A lot of conjugated billirubin filtrates from the glomerular. The billirubin into the intestine decreases, so the bilinogen production decreases, too.