Biology 9th class MCQs and Questions
Chapter: 06
“Enzymes”
1. All the chemical reactions taking place in the body are called
a) Catabolism
b) Metabolism
c) Metabolites
d) Anabolism
Sol: (b) Metabolism
2. The term metabolism derived from
a) Latin word
b) Greek word
c) Persian word
d) French word
Sol: (b) Greek word
3. The word “metabolism” meaning
a) Altar
b) Change
c) Break
d) Make
Sol: (b) Change
4. Who gave the concept of “metabolism” firstly
a) Ibn Rushd
b) Ibn Khaldun
c) Ibn Sina
d) Ibn-e-Nafees
Sol: (d) Ibn-e-Nafees
5. The biochemical reaction in which larger molecules are synthesized is called
a) Catabolism
b) Anabolism
c) Biocatalyst
d) Metabolism
Sol: (b) Anabolism
6. The biochemical reaction in which larger molecules are broken down is called
a) Catabolism
b) Anabolism
c) Metabolism
d) Enzymes
Sol: (a) Catabolism
7. Energy is released in
a) Catabolism
b) Anabolism
c) Metabolism
d) All of the above
Sol: (a) Catabolism
8. Energy is utilized in
a) Metabolism
b) Anabolism
c) Catabolism
d) None of the above
Sol: (b) Anabolism
9. The molecules that which enzyme act are called
a) Products
b) Substrate
c) Biocatalyst
d) Prosthetic group
Sol: (a) Substrate
10. The minimum energy required to start a reaction called
a) Chemical energy
b) Mechanical energy
c) Activation energy
d) Gravitational energy
Sol: (c) Activation energy
11. Enzymes lower the activation energy in different ways like
a) They may alter the shape of the substrate
b) Some enzymes do so by disrupting the charge distribution on substrates
c) By bringing substrate in the correct orientation to react
d) All of these
Sol: (d) all of these
12. Who firstly used the term “enzyme”
a) Alexander Fleming
b) Winhelm Kuhne
c) Jabir Bin Hayan
d) Thomas Edison
Sol: (b) Winhelm Kuhne
13. When did Winhelm Kuhne firstly use the term enzyme
a) 1878
b) 1787
c) 1778
d) 1887
Sol: (a) 1878
14. Almost all enzymes are
a) Lipids
b) Carbohydrates
c) Proteins
d) Compounds
Sol: (c) Proteins
15. Enzymes are made up of
a) Proteins
b) Amino acids
c) Lipids
d) Fats
Sol: (b) Amino acids
16. The enzyme which works inside the cell are called
a) Extracellular enzyme
b) Intracellular enzyme
c) Active site
d) All of these
Sol: (b) Intracellular enzyme
17. The catalytic region of an enzyme known as
a) Activators
b) Active site
c) Substrate
d) Inhibitors
Sol: (b) Active site
18. Enzyme activity can be regulated by
a) Inhibitors
b) Activators
c) Both (a) and (b)
d) None of the above
Sol: (c) Both (a) and (b)
19. Some enzymes require non-protein molecules or ions called
a) Cofactor
b) Coenzyme
c) Prosthetic group
d) All of the above
Sol: (a) Cofactor
20. Flavin and heme are
a) Organic cofactor
b) Inorganic cofactor
c) Both (a) and (b)
d) None of the above
Sol: (a) Organic factor
21. If organic cofactors are tightly bound to the enzyme, then they are called
a) Coenzyme
b) Prosthetic group
c) Active site
d) Saturation of enzyme
Sol: (b) Prosthetic group
22. If organic cofactors are loosely attached to enzyme then they are called
a) Prosthetic group
b) Activators
c) Prosthetic group
d) Coenzyme
Sol: (d) Coenzyme
23. Which of the following vitamins act as a coenzyme?
a) Thiamine
b) Riboflavin
c) Folic acid
d) All of these
Sol: (d) All of these
24. Which enzymes are used for the removal of protein stains from clothes
a) Lipase enzyme
b) Protease enzyme
c) Amylase enzyme
d) Xylanase enzyme
Sol: (b) Protease enzyme
25. Enzymes break starch to………..its viscosity that aids in making paper
a) Lower
b) Increase
c) Equal
d) None of the above
Sol: (a) Lower
26. The optimum temperature for the maximum working speed of human enzymes
a) 38℃
b) 39℃
c) 36.7℃
d) 37℃
Sol: (d) 37℃
27. Which enzyme is used in dishwashing to remove resistant starch residues?
a) Lipase
b) Amylase
c) Ligase
d) All of these
Sol: (b) Amylase
28. All enzyme work at their maximum rate at a narrow range of PH called
a) PH
b) Optimum temperature
c) Optimum PH
d) Denaturation of an enzyme
Sol: (c) Optimum PH
29. Change in a PH can affect the ionization of the
a) Lipids
b) Carbohydrates
c) Proteins
d) Amino acids
Sol: (d) Amino acids
30. Pepsin is active in an acidic medium and has
a) Low PH
b) High PH
c) Moderate PH
d) Zero PH
Sol: (a) Low PH
31. Trypsin (work in the small intestine) shows its activity in an alkaline medium has
a) High PH
b) Low PH
c) Zero PH
d) All of the above
Sol: (a) High PH
32. Which enzyme is best for weight loss
a) Lipase
b) Protease
c) Amylase
d) All of the above
Sol: (d) All of the above
33. Who proposed the “Lock and key model”
a) Emil Fisher
b) Daniel Koshland
c) Winhelm Kuhne
d) Thomas Edison
Sol: (a) Emil fisher
34. When did “Emil Fisher” propose the “Lock and key model”
a) 1895
b) 1896
c) 1994
d) 1893
Sol: (c) 1894
35. Which model explains enzyme specificity
a) Lock and key model
b) Induced fit model
c) None of the above
d) All of these
Sol: (a) Lock and key model
36. Who proposed the “Induced fit Model”
a) Emil Fisher
b) Daniel Koshland
c) Charles Darwin
d) None of the above
Sol: (b) Daniel Koshland
37. When did American Biologist suggest a modification to the lock and key model and proposed the “Induced fit model”
a) 1958
b) 1968
c) 1938
d) 1987
Sol: (a) 1958
38. Which model of the enzyme is more acceptable
a) Lock and key model
b) Induced fit model
c) Both (a) and (b)
d) None of the above
Sol: (b) induced fit model
39. How many enzymes are known
a) 1000
b) 2000
c) 3000
d) 3500
Sol: (b) 2000
40. Which enzyme is used to break peptides bonds in proteins
a) Amylase
b) Ligase
c) Protease
d) All of these
Sol: (c) Protease
41. Starch is broken down by an enzyme called
a) Pepsin
b) Lipase
c) Ligase
d) Amylase
Sol: (d) amylase
42. Which enzyme act only on lipids
a) Trypsin
b) Pepsin
c) Lipase
d) Ligase
Sol: (c) Lipase
43. Specificity of different enzymes is determined by the shapes of their
a) Substrate
b) Active site
c) Product
d) All of these
Sol: (b) Active site
An important definition of this chapter that is asked in the previous board:
1. Define metabolism
2. Define catabolism
3. Define enzymes
4. Define activation energy
5. Define coenzyme
6. Define cofactors
7. Define optimum temperature
8. Define PH
9. Define substrate and product.
10. Explain the role of biological detergent in the use of enzymes.
11. Define the prosthetic group.
12. Define amylase
13. Define lipase.
Important Questions asked in the previous board of Pakistan
1. How enzyme reduces activation energy?
2. Difference between intracellular and extracellular enzymes with examples.
3. Write any 6 characteristics of enzymes?
4. Write the use of enzymes?
5. Write the mechanism of an enzyme’s action.
6. Write and explain models of enzyme action with diagrams
7. Prove that enzymes are very specific?
(Work hard, “A good Leader is not made overnight”.) (“Take challenges, challenges teach people what they are capable of doing”)
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