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ENZYMES- Part 18
See all quizzes of ENZYMES- Part 18 here:
1 An example of feedback inhibition is
(A) Allosteric inhibition of hexokinase by glucose-
6-phosphate
(B) Cyanide action on cytochrome
(C) Sulpha drug on folic acid synthesizer bacteria
(D) Reaction between succinic dehydrogenase
and succinic acid
2. Feedback term refers to
(A) Effect of substrate on rate of enzymatic
reaction
(B) Effect of end product on rate reaction
(C) Effect of enzyme concentration on rate of
reaction
(D) Effect of external compound on rate of
reaction
3. Allosteric inhibition
(A) Makes active site unifit for substrate
(B) Controls excess formation and end product
(C) Both (A) and (B)
(D) None of these
4. The ratio of enzyme to substrate molecules
can be as low as
(A) 1 : 100,000 (B) 1 : 500,000
(C) 1 : 10,000 (D) 1 : 1,000
5. Vitamin B2 is component of coenzyme:
(A) Pyridoxal phosphate
(B) TPP
(C) NAD
(D) FMN/FAD
6. Km value of enzyme is substrate concentration
at
(A) ½ Vmax (B) 2 Vmax
(C) ½ Vmax (D) 4 Vmax
7. Part of enzyme which combines with nonprotein
part to form functional enzyme is
(A) Apoenzyme (B) Coenzyme
(C) Prosthetic group (D) None of these
8. Who got Nobel Prize in 1978 for working
on enzymes?
(A) Koshland (B) Arber and Nathans
(C) Nass and Nass (D) H.G. Khorana
9. Site of enzyme synthesis in a cell is
(A) Ribosomes (B) RER
(C) Golgi bodies (D) All of these
10. The fruit when kept is open, tastes bitter
after 2 hours because of
(A) Loss of water from juice
(B) Decreased concentration of fructose in juice
(C) Fermentation by yeast
(D) Contamination by bacterial enzymes
11. Hexokinase (Glucose + ATP → Glucose-6–
P + ADP) belongs to the category:
(A) Transferases (B) Lysases
(C) Oxidoreductases (D) Isomerases
12. Which enzyme is concerned with transfer
of electrons?
(A) Desmolase (B) Hydrolase
(C) Dehydrogenase (D) Transaminase
13. The best example of extracellular enzymes
(exoenzyme) is
(A) Nucleases
(B) Digestive enzymes
(C) Succinic dehydrogenase
(D) None of these
14. Which mineral element controls the
activity of Nitrate reductase ?
(A) Fe (B) Mo
(C) Zn (D) Ca
15. Name the enzyme that acts both as
carboxylase at one time and oxygenase
at another time.
(A) PEP carboxylase
(B) RuBP carboxylase
(C) Carbonic anyhdrase
(D) None of these
16. A metabolic pathways is a
(A) Route taken by chemicals
(B) Sequence of enzyme facilitated chemical
reactions
(C) Route taken by an enzyme from one reaction
to another
(D) Sequence of origin of organic molecules
17. The energy required to start an enzymatic
reaction is called
(A) Chemical energy (B) Metabolic energy
(C) Activation energy (D) Potential energy
18. Out of the total enzymes present in a cell,
a mitochondrion alone has
(A) 4% (B) 70%
(C) 95% (D) 50%
19. Creatine phosphokinase isoenzyme is a
marker for
(A) Kidney disease
(B) Liver disease
(C) Myocardial infarction
(D) None of these
20. Which inactivates an enzyme by occupying
its active site?
(A) Competitive inhibitor
(B) Allosteric inhibitor
(C) Non-competitive inhibitor
(D) All of these
21. Which one is coenzyme?
(A) ATP (B) Vitamin B and C
(C) CoQ and CoA (D) All of these
22. The active site of an enzyme is formed by
(A) R group of amino acids
(B) NH2 group of amino acids
(C) CO group of amino acids
(D) Sulphur bonds which are exposed
23. Carbonic anhydrase enzyme has maximum
turn over number (36 million). Minimum
turn over number for an enzyme:
(A) DNA polymerase
(B) Lysozyme
(C) Penicillase
(D) Lactase dehydrogenase
24. In cell, digestive enzymes are found
mainly in
(A) Vacuoles (B) Lysosomes
(C) Ribosomes (D) Lomasomes
25. Substrate concentration at which an
enzyme attains half its maximum velocity
is
(A) Threshold value
(B) Michaelis-Menton constant
(C) Concentration level
(D) None of these
26. Which enzyme hydrolyses starch?
(A) Invertase (B) Maltase
(C) Sucrase (D) Diastase
27. Enzymes functional in cell or mitochondria
are
(A) Endoenzymes (B) Exoenzymes
(C) Apoenzymes (D) Holoenzymes
28. The enzymes present in the membrane of
mitochondria are
(A) Flavoproteins and cytochromes
(B) Fumarase and lipase
(C) Enolase and catalase
(D) Hexokinase and zymase
29. A mitochondrial marker enzyme is
(A) Aldolase
(B) Amylase
(C) Succinic dehydrogenase
(D) Pyruvate dehydrogenase
ENZYMES 175
30. The enzyme used in polymerase chain
reaction (PCR) is
(A) Taq polymerase (B) RNA polymerase
(C) Ribonuclease (D) Endonuclease
