Download Questions for Enzyme - I

MCQS IN ENZYMES – I
1. Class of enzyme that is involved in linking of two molecules at the expense of energy
is
a. Ligase
b. Lyase
c. Linker enzyme
d. Reductase
2. Lactate Dehydrogenase belongs to following class of enzyme
a. Transferase
b. hydrolase c. Isomerase d. Oxido reductase
3. The “Prosthetic group” is
a. Non protein part of enzyme, tightly bound
b. Protein part of the enzyme
c. Never a part of the enzyme
d. Protein part of enzyme, loosely bound
4. Coenzyme that is involved in transfer of H2 atoms is
a. NAD, FAD
b. Coenzyme – A
c. Pyridoxal phosphate
pyro phosphate
d. Thiamine
5. Coenzyme that is involved in transfer of amino group is
a. NAD, FAD
b. Coenzyme – A
c. Pyridoxal phosphate
pyro phosphate
d. Thiamine
6. Active site of an enzyme is
a. Made up of catalytic site & substrate binding site
b. Flexible in nature – changes its conformation upon substrate binding
c. Specificity of enzyme resides in active site
d. All of the above
7. Most accepted theory for substrate binding with the enzyme is
a. Lock & key theory
b. Koshlands induced fit theory
c. I.U.B theory
d. Allostearic theory
8. Following statement is true regarding Km Value
a. Signifies the affinity of enzyme for substrate
b. Never altered by enzyme inhibitors
c. It is the conc. Of enzyme at half maximal velocity
d. One enzyme can have different Km values with same substrate
9. Graph obtained when substrate conc. Is plotted Vs velocity
a. Bell shaped
b. Sigmoid shaped
c. Rectangular hyperbola shaped
d. Can be of any shape depending on prevailing conditions
10. Mechanism of action of enzymes is
a. By reducing the activation energy of the reaction
b. By providing alternate pathways requiring less energy
c. By forming enzyme – substrate complex which dissociates later forming products
d. All of the above
Keys: 1 - a
2–d
3-a 4-a
5-c
6-d
7-b
8-a
9-c
10 - d
Questions on Enzyme - I
1. What are enzymes? Classify them giving one example each. Indicate the reaction catalyzed
by the enzyme in each class.
(5)
2. Classify enzymes with an example for each class
(5)
3. Name the classes into which the enzymes are classified
(3)
4. Classify enzymes with suitable examples.
(3)
5. Classify enzymes and list one example for each class indicating the reaction catalyzed. (4)
6. Lyases.
(3)
7. Give 2 examples for each of the following.
(1 mark each)
a) Oxidoreductases b) Transferases c) Hydrolases d) Lyases e) Isomerases f) Ligases
8. What are coenzymes? Name four coenzymes and give examples of enzyme reactions where
each coenzyme takes part.
(4)
9. Name zinc containing enzyme and its catalytic role.
(3)
10. *Mention four copper containing enzymes.
(3)
11. Define absolute specificity of enzyme. Give two examples.
(3)
12. Km value.
(3)
13. Define Km value. What is its significance?
(3)
14. What is Km value? Explain its importance
(3)
15. What are enzymes? Describe the factors affecting velocity of enzyme-catalyzed reaction.
(5)
16. Explain the influence of various factors on enzyme activity.
(5)
17. Factors affecting rate of enzymatic reaction
(4)
18. What are the factors that influence enzyme activity? Discuss briefly the role of metals in
enzyme activity.
(5)
19. Give an account of effect of substrate concentration, pH and temperature on enzyme activity.
Explain the significance of Km and Vmax.
(5)
20. Explain how change in temperature alters the enzyme activity.
(3)
21. Explain how change in pH alters the enzyme activity.
(3)