Part One:  Single choice questions: (2’ each, total 30 marks)

1. The chemical bond linking nucleotides together to form nucleic acid molecule is

1.   hydrogen bond
2.   peptide bond
3. ionic bond
4. 3’,5’-phosphodiester linkage

2. The coenzyme containing vitamin B2 is

1. NAD⁺   
2. FAD
3. TPP
4. CoA

3.  Amino groups in an amino acid are metabolized by

1. Oxidative deamination
2. Transamination
3. Both of the above
4. None of the above

4. NAPDH utilized for synthesis of fatty acids can be generated from

1. Glycolysis
2. The pentose phosphate pathway
3. The citric acid cycle
4. Mitochondrial malate dehydrogenase

5． Lesch-Nyhan syndrome occurs due to deficiency of

a. tyrosine hydrxylase  b.  homogentisate oxidase  c. HGPRT d. LPL

6. Marasmus and Kwashiorkor are diseases related to：

a.  Protein energy malnutrition.

b.  Carbohydrate malnutrition.

c.  Dietary fat malnutrition

d.  All of the above combined together

7. In the presence of hyperammonia, production of which of the following amino acids is always increased?

a.  Arginine      b. Glutamine     c.  Glutamate     d.  Glycine

8. The metabolites converted from cholesterol in the body are:

a.  bile acids

b.  vitamin D

c.  sterol hormones

d.  all of the above

9. Muscle glycogen cannot contribute directly to plasma glucose is due to

1. Lack of phosphorylase
2. Lack of glucokinase
3. Lack of glucose-6-phosphatase
4. Muscle tissue is the organ storing glycogen
   10. The key enzyme of mobilization of stored fat is

a.  HMG CoA synthetase

b.  hormone-sensitive triglyceride lipase, HSL

c.  HMG CoA reductases

d.  lipoprotein lipase

11. During transamination, coenzyme pyridoxal phosphate serves as a carrier of

a.  one carbon unit

b.  methyl group

c.  carboxyl group

d.  amino group

12. The urea cycle occurs only in the       

a.  liver

b.  kidney

c.  brain

d.  muscle

13. Which one of the following amino acids is acidic amino acid at physiological pH?

a.  Lysine

b.  Histidine

c.  Aspartic acid

d.  Valine

14. Nucleotides are made up of

a.  a nitrogenous base and sugar

b.  a nitrogenous base and phosphate

c.  phosphate and sugar

d.  a nitrogenous base , sugar and phosphate

15. The number of hydrogen bonds between cytosine and guanine is  

a. 1          b.  2            c. 3           d. 4

Part Two: Blank filling: (1’ each, total 6 marks)

1. The rate-limiting enzyme in biosynthesis of cholesterol is                    .
2. Posttranscriptional processing of mRNA in eukaryotic cells includes removal of introns, 5’ capping and                       .
3.                 is the only hormone to reduce the blood glucose level.
4.            is the major disposal form of amino groups derived from amino acids.
5.                is a symptom of yellowing of the skin and the whites of the eyes caused by an accumulation of bilirubin in the blood.
6. Xenobiotics such as drugs, pollutants and food additives could be chemically metabolized to form water-soluble derivatives in the liver and then be excreted from the body, these processes are named            .

Part Three: MARK AS TRUE OR FALSE. (1’ each, total 10 marks)

1. Operon is the basic unit of prokarytoic gene expression and regulation
2. A vector in DNA cloning must be capable of autonomous replication within the host cell.
3. A competitive inhibitor of an enzyme decreases Km and Vmax.
4. Gluconeogenesis is not the reversal of glycolysis.      
5. LDL is involved in reverse cholesterol transport.
6. Citric acid cycle is the final common pathway for the aerobic oxidation of carbohydrate, lipid, and protein.
7. Isoenzymes are distinct molecular forms of enzymes catalyzing different reactions.
8. The key enzymes of glycolysis are hexokinase, phosphofructokinase and pyruvate dehydrogenase.
9. Protein denaturation is due to changes in amino acid sequence.
10. The 16-C saturated fatty acid palmitate is the final product of the fatty acid synthase complex.

Part Four: Explain the conceptions (choose 6 from 8, 3’ each, total 18 marks)

1. glycoprotein

2. promoter

3. lipoprotein

4. ketone bodies

5. electron transport chain

6. second messenger

7. DNA cloning

8. gluconeogenesis

Part Five: Short answering questions: (choose 6 from 7,  6’ each, total 36 marks)

1.  What are the major functions of plasma albumin?

2. What is zymogen? Expain the physiological significance of activation of zymogen
3. Describe briefly functions of the three major types of RNA.
4. Describe briefly characteristics of the double helical structure of DNA.
5. What are sources of blood ammonia?
6. What are the general features of DNA replication?
7. Elucidate the biological significance of glycolysis.