Enzymology (Biochemistry) BSc MCQs Set-2

Biochemistry Mcqs

1. In non competitive enzyme activity inhibition, inhibitor 

(A) Increases Km 
(B) Decreases Km 
(C) Does not affect Km 
(D) Increases Km 

Answer:(C) Does not affect Km 

2. An enzyme catalyzing oxidoreduction, using oxygen as hydrogen acceptor is 

(A) Cytochrome oxidase 
(B) Lactate dehydrogenase 
(C) Malate dehydrogenase 
(D) Succinate dehydrogenase 

Answer:(A) Cytochrome oxidase

3. The enzyme using some other substance, not oxygen as hydrogen acceptor is 

(A) Tyrosinase 
(B) Succinate dehydrogenase 
(C) Uricase 
(D) Cytochrome oxidase

Answer: (B) Succinate dehydrogenase

4. An enzyme which uses hydrogen acceptor as substrate is 

(A) Xanthine oxidase 
(B) Aldehyde oxidase 
(C) Catalase
(D) Tryptophan oxygenase 

Answer:(C) Catalase

5. Enzyme involved in joining together two substrates is 

(A) Glutamine synthetase 
(B) Aldolase 
(C) Guanine deaminase 
(D) Arginase 

Answer:(A) Glutamine synthetase

6. The pH optima of most of the enzymes is

(A) Between 2 and 4 
(B) Between 5 and 9 
(C) Between 8 and 12
(D) Above 12 

Answer:(B) Between 5 and 9 

7. Coenzymes are 

(A) Heat stable, dialyzable, non protein organic molecules 
(B) Soluble, colloidal, protein molecules 
(C) Structural analogue of enzymes 
(D) Different forms of enzymes 

Answer:(A) Heat stable, dialyzable, non protein organic molecules

8. An example of hydrogen transferring coenzyme is 

(A) CoA 
(B) NAD+ 
(C) Biotin 
(D) TPP 

Answer:(B) NAD+

9. An example of group transferring coenzyme is 

(A) NAD+ 
(B) NADP+ 
(C) FAD 
(D) CoA

Answer:(D) CoA

10. Cocarboxylase is 

A) Thiamine pyrophosphate
(B) Pyridoxal phosphate 
(C) Biotin 
(D) CoA 

Answer:(C) Biotin

11. A coenzyme containing non aromatic hetero ring is 

(A) ATP 
(B) NAD 
(C) FMN 
(D) Biotin 

Answer:(D) Biotin

12. A coenzyme containing aromatic hetero ring is 

(A) TPP 
(B) Lipoic acid 
(C) Coenzyme Q 
(D) Biotin 

Answer:(A) TPP

13. Isoenzymes are 

(A) Chemically, immunologically and electrophoretically different forms of an enzyme 
(B) Different forms of an enzyme similar in all properties 
(C) Catalysing different reactions 
(D) Having the same quaternary structures like the enzymes 

Answer:(A) Chemically, immunologically and electrophoretically different forms of an enzym

14. Isoenzymes can be characterized by 

(A) Proteins lacking enzymatic activity that are necessary for the activation of enzymes 
(B) Proteolytic enzymes activated by hydrolysis 
(C) Enzymes with identical primary structure 
(D) Similar enzymes that catalyse different reactions 

Answer:(B) Proteolytic enzymes activated by hydrolysis

15. The isoenzymes of LDH 

(A) Differ only in a single amino acid 
(B) Differ in catalytic activity 
(C) Exist in 5 forms depending on M and H monomer contents 
(D) Occur as monomers 

Answer:(C) Exist in 5 forms depending on M and H monomer contents

16. The normal value of CPK in serum varies between 

(A) 4–60 IU/L 
(B) 60–250 IU/L 
(C) 4–17 IU/L 
(D) > 350 IU/L

 Answer:(A) 4–60 IU/L 

17. Factors affecting enzyme activity: 

(A) Concentration 
(B) pH 
(C) Temperature 
(D) All of these 

Answer:(D) All of these 

18. The normal serum GOT activity ranges from 

(A) 3.0–15.0 IU/L 
(B) 4.0–17.0 IU/L 
(C) 4.0–60.0 IU/L 
(D) 0.9–4.0 IU/L 

Answer:(B) 4.0–17.0 IU/L 

19. The normal GPT activity ranges from 

(A) 60.0–250.0 IU/L 
(B) 4.0–17.0 IU/L 
(C) 3.0–15.0 IU/L 
(D) 0.1–14.0 IU/L 

Answer:(C) 3.0–15.0 IU/L

20. The normal serum acid phosphatase activity ranges from 

(A) 5.0–13.0 KA units/100 ml 
(B) 1.0–5.0 KA units/100 ml 
(C) 13.0–18.0 KA units/100 ml 
(D) 0.2–0.8 KA units/100 ml 

Answer:(B) 1.0–5.0 KA units/100 ml 

21. The normal serum alkaline phosphatase activity ranges from 

(A) 1.0–5.0 KA units/100 ml 
(B) 5.0–13.0 KA units/100 ml 
(C) 0.8–2.3 KA units/100 ml 
(D) 13.0–21.0 KA units/100 ml

Answer:(B) 5.0–13.0 KA units/100 ml

22. In early stages of myocardial ischemia the most sensitive indicator is the measurement of the activity of 

(A) CPK 
(D) LDH 

Answer:(A) CPK 

23. Serum acid phosphatase level increases in 

(A) Metastatic carcinoma of prostate 
(B) Myocardial infarction 
(C) Wilson’s disease 
(D) Liver diseases 

Answer:(A) Metastatic carcinoma of prostate

24. Serum alkaline phosphatase level increases in 

(A) Hypothyroidism
(B) Carcinoma of prostate 
(C) Hyperparathyroidism 
(D) Myocardial ischemia 

Answer:(C) Hyperparathyroidism

25. Serum lipase level increases in 

(A) Paget’s disease 
(B) Gaucher’s disease 
(C) Acute pancreatitis 
(D) Diabetes mellitus 

Answer:(C) Acute pancreatitis

26. Serum ferroxidase level decreases in 

(A) Gaucher’s disease 
(B) Cirrhosis of liver 
(C) Acute pancreatitis 
(D) Wilson’s disease

Answer:(D) Wilson’s disease

27. The isoenzymes LDH5 is elevated in 

(A) Myocardial infarction 
(B) Peptic ulcer 
(C) Liver disease 
(D) Infectious diseases 

Answer:(C) Liver disease 

28. On the third day of onset of acute myocardial infarction the enzyme elevated is 

(A) Serum AST 
(B) Serum CK 
(C) Serum LDH 
(D) Serum ALT 

Answer:(C) Serum LDH

29. LDH1 and LDH2 are elevated in 

(A) Myocardial infarction 
(B) Liver disease 
(C) Kidney disease 
(D) Brain disease 

Answer:(A) Myocardial infarction

30. The CK isoenzymes present in cardiac muscle is

(A) BB and MB 
(B) MM and MB 
(C) BB only 
(D) MB only

Answer:(B) MM and MB