11th Class Biology Chapter 03 MCQs with Answers

Welcome to the 11th Class Biology Chapter 03 MCQs Online Test. We are presenting you with top MCQ questions from the 11th Class Biology Chapter Enzymes.

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11th Class Biology Chapter 03 MCQs with Answers

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MCQs Class 11 Biology with Answers

The purpose of these online MCQs tests is to help you evaluate your 11th Class Biology Chapter 03 MCQs. These Multiple Choice Questions (MCQs) will prepare you for your academic success in the 11th Class Exams. 11th Class Biology Chapters include Chapter 01 Introduction, Chapter 02 Biological Molecules, Chapter 03 Enzymes, Chapter 04 The Cell, Chapter 05 Variety of Life, Chapter 06 Kingdom Prokaryotae, Chapter 07 The Kingdom Protista, Chapter 08 Fungi, Chapter 09 Kingdom Plantae, Chapter 10 Kingdom Animalia, Chapter 11 Bioenergeties, Chapter 12 Nutrition, Chapter 13 Gaseous Exchange and Chapter 14 Transport

What are Enzymes?

Enzymes are proteins that help speed up chemical reactions in our bodies. Enzymes are essential for digestion, liver function, and much more. Too much or too little of a certain enzyme can cause health problems. Enzymes in our blood can also help healthcare providers check for injuries and diseases.

Enzymes are proteins that help speed up metabolism, or the chemical reactions in our bodies. They build some substances and break others down. All living things have enzymes. One of the most important roles of enzymes is to aid in digestion. Digestion is the process of turning the food we eat into energy. For example, there are enzymes in our saliva, pancreas, intestines, and stomach. They break down fats, proteins, and carbohydrates. Enzymes use these nutrients for growth and cell repair.

11th Class Biology Chapter 03 MCQs: Enzymes

1. The catalytic activity of an enzyme is restricted to its small portion called choose one:

  1. Intermediate
  2. Above all
  3. Passive site
  4. Active site

2. An activated enzyme made of polypeptide chain and a co-factor is choose one:

  1. Co-enzyme
  2. Substrate
  3. Apoenzyme
  4. Holoenzyme

3. The rate of reaction of enzyme directly depends upon choose one:

  1. Maximum pH level
  2. Amount of enzyme present at a specific time at unlimited substrate concentration
  3. Nature of substrate
  4. Low temperature

4. Koshland in 1959 proposed the modified form of choose one:

  1. Unit membrane model
  2. Reflective index model
  3. Fluid mosaic model
  4. Induce fit model

5. The reversible inhibitors usually constitute choose one:

  1. No linkage with enzyme
  2. Weak linkage with enzyme
  3. Medium linkag
  4. Strong linkage with enzyme

6. The detachable co-factor of an enzyme (if it is an inorganic ion) is called

  1. Activator
  2. Catalytic
  3. Aqueous medium
  4. Apoenzyme

7. If the non-protein part is covalently bonded to the protein part of an enzyme, it is called as choose one:

  1. Prosthetic group
  2. Catalytic
  3. Activator
  4. Optimum

8. An enzyme with its coenzyme or prosthetic group, removed is called as choose one:

  1. Apoenzyme
  2. Aqueous medium
  3. Activato
  4. Prosthetic group

9. The active site of an enzyme is composed of binding site and choose one:

  1. Apoenzyme
  2. Catalytic site
  3. Prosthetic site
  4. Substrate site

10. Medium required for Enzymes vigorous activity choose one:

  1. Colloidal
  2. Transparent
  3. Aqueous
  4. Gel

11. Every enzyme functions effectively at choose one:

  1. 9.00 pH
  2. Optimum pH
  3. 2.00 pH
  4. 7.00 pH

12. Almost all enzymes are choose one:

  1. Fibrous proteins
  2. Globular proteins
  3. Triangular protein
  4. All of the above

13. The optimum pH value for pancreatic lipase is choose one:

  1. 8.00
  2. 10.00
  3. 7.00
  4. 9.00

14. The enzymes involved in the cellular respiration in eukaryotes are found in choose one:

  1. Chloroplas
  2. Aqueous medium
  3. Mitochondria
  4. Nucleoplasm

15. Even traces of enzymes can bring about change in large amount of choose one:

  1. Catalytic
  2. Activato
  3. Substrate
  4. Optimum

16. Co-enzymes choose one:

  1. Globular protein
  2. Oral cavity
  3. Vitamin
  4. Co-factors

17. Salivary amylase choose one:

  1. Oral cavity
  2. Co-factors
  3. Vitami
  4. Globular protein

18. Metal ions choose one:

  1. Vitami
  2. Oral cavity
  3. Globular protein
  4. Co-factors

19. Amino acids choose one:

  1. Globular protein
  2. Oral cavity
  3. Chloroplast
  4. Vitamin

20. Photosynthesis choose one:

  1. Oral cavity
  2. Vitamin
  3. Globular protein
  4. Chloroplast

21. Emil Fischer choose one:

  1. Cyanide
  2. Lock and key model
  3. Temperature
  4. Specific in action

22. Inhibitors choose one:

  1. Temperature
  2. Cyanide
  3. Lock and key model
  4. Specific in action

23. Activation energy choose one:

  1. Temperature
  2. Cyanide
  3. Lock and key model
  4. Specific in action

24. Enzymes choose one:

  1. Temperature
  2. Specific in action
  3. Reversible inhibitors
  4. Cyanide

25. Competitive choose one:

  1. Reversible inhibitors
  2. Lock and key model
  3. Specific in actio
  4. Temperature

26. The catalytic activity of an enzyme is restricted to its small portion called choose one:

  1. Active site
  2. Passive sit
  3. Allosteric site
  4. All Choices are correc

27. An activated enzyme made of polypeptide chain and a co-factor is choose one:

  1. Coenzyme
  2. Substrate
  3. Apoenzyme
  4. Holoenzyme

28. Koshland in 1959 proposed choose one:

  1. Fluid mosaic model
  2. Induce fit model
  3. Lock and key model
  4. Reflective index model

29. Chemical nature of enzymes is choose one:

  1. Lipids
  2. Steroids
  3. Proteinaceous
  4. All (A), (B) and (C)

30. Who proposed “lock and key” model to study enzyme-substrate interaction?

  1. Koshland (1959)
  2. Wilhelm Kuhne(1878)
  3. Fischer (1898)
  4. None of these

31. In human body the optimum temperature for enzymatic activities is choose one:

  1. 37°C
  2. 40°C
  3. 25°C
  4. 30°C

32. Optimum pH value for pepsin is choose one:

  1. 5.5
  2. 7.4
  3. 4.1
  4. 1.4

33. Competitive inhibitors stop an enzyme from working by choose one:

  1. Changing the shape of the enzyme
  2. Merging with the substrate instead
  3. Blocking the active site of the enzyme
  4. Combining with the product of the reaction

34. The enzymes are sensitive to choose one:

  1. Changes in pH
  2. Changes in temperature
  3. Both (A) and (B)
  4. None of these

35. Enzyme B requires Zn2+ in order to catalyze the conversion of substrate X. The zinc is best identified as choose one:

  1. Coenzyme
  2. Activator
  3. Substrate
  4. Product

36. The enzyme minus its coenzyme is referred to as the choose one:

  1. Iso-enzyme
  2. Metalloenzyme
  3. Apoenzyme
  4. All of these

37. The “lock and key” model of enzyme action illustrates that a particular enzyme molecule choose one:

  1. Forms a permanent enzyme-substrate complex
  2. May be destroyed and resynthesized several times
  3. Interacts with a specific type of substrate molecule
  4. Reacts at identical rates under all conditions

38. Consider this reaction. A + B  C + D + energy.

  1. This reaction is exergonic
  2. An enzyme could still speed the reaction
  3. A and B are reactants; C and D are products
  4. All of these are correct

39. An inhibitor that changes the overall shape and chemistry of an enzyme is known as choose one:

  1. Auto-steric inhibitor
  2. Competitive inhibitor
  3. Steric inhibitor
  4. Noncompetitive inhibitor

40. Non-protein components of enzymes are known as choose one:

  1. Coenzymes
  2. Activators
  3. Cofactors
  4. All (A), (B) and (C)

41. Which type of inhibitor is shown in this diagram?

  1. Competitive
  2. Non-competitive
  3. Allosteric
  4. Both (B) and (C)

42. An enzyme is generally named by adding to the end of the name

  1. “-ase”. coenzyme
  2. “-ase”. cell in which it is found
  3. “-ose”. substrate
  4. “-ase”. substrate

43. The minimum amount of energy needed for a process to occur is called the choose one:

  1. Minimal energy theory
  2. Process energy
  3. Kinetic energy
  4. Activation energy

44. A student conducts an experiment to test the efficiency of a certain enzyme. Which would probably not result in a change in the enzyme’s efficiency?

  1. Adding an acidic solution to the setup
  2. Adding more substrate but not enzyme
  3. Increasing temperature of solution
  4. All (A), (B) and (C) change enzyme’s efficiency

45. Enzymes function as choose one:

  1. Organic catalysts
  2. Inorganic catalysts
  3. Inhibitors
  4. All of these

46. A catalyst is a chemical involved in, but not __ by, a chemical reaction.

  1. Supported
  2. Changed
  3. Controlled
  4. All of these

47. Many enzymes function by the activation energy of reactions.

  1. Increasing
  2. Promoting
  3. Lowering
  4. Both (A) and (B)

48. An uncatalysed reaction requires a choose one:

  1. Higher activation energy
  2. Lower activation energy
  3. Balanced activation energy
  4. All of these

49. The binding of the substrate to the enzyme alters the structure of the enzyme choose one:

  1. Lock and key hypothesis
  2. Induced fit hypothesis
  3. Fisher’s hypothesis
  4. D.D. Wood’s hypothesis

50. They are non-protein organic molecules bound to enzymes near the active site choose one:

  1. Activators
  2. Coenzymes
  3. Holoenzymes
  4. All of these

51. The first step in any reaction catalysed by an enzyme is the formation of a specific association between the molecules called choose one:

  1. Enzyme-product complex
  2. Enzyme-intermediate complex
  3. Enzyme-substrate complex
  4. None of these

52. The function of competitive inhibitors is defined by their ability to interact or bind to choose one:

  1. The active site of an enzyme
  2. Regulatory sub-units of an enzyme
  3. Non-competitive inhibitor
  4. Enzyme cofactors

53. If an enzyme solution is saturated with substrate, the most effective way to obtain an even faster yield of products would be choose one:

  1. Add more of the enzymes
  2. Add more substrate
  3. Add an allosteric inhibitor
  4. Add a non-competitive inhibitor

54. When the final product of a metabolic pathway turn off the first step of metabolic pathway it is choose one:

  1. Positive feed back
  2. Negative feed back
  3. Competitive feed back
  4. Both (A) and (C)

55. When the inhibitory chemical, which does not have to resemble the substrate, binds to the enzyme other than at the active site is called choose one:

  1. Noncompetitive Inhibition
  2. Competitive Inhibition
  3. Uncatalysed reaction
  4. All (A), (B) and (C)

56. Which one is not attribute of enzyme?

  1. Specific in nature
  2. Protein in chemistry
  3. Consumed in reaction
  4. Increases rate of reactic

57. Which one inactivates an enzyme by indirectly changing the shape pf the active site of an enzyme?

  1. Non-competitive inhibitor
  2. Competitive inhibitor
  3. Coenzyme
  4. Activator

58. The enzymes are classified into choose one:

  1. Five groups
  2. Three groups
  3. Six groups
  4. Four groups

59. Non-proteinaceous part of holoenzyme is choose one:

  1. Prosthetic group
  2. Apoenzyme
  3. Tubulin
  4. None of these

60. Enzymes are highly specific for a given substrate which is due to the shape of their choose one:

  1. Active site
  2. Allosteric site
  3. Non-competitive site
  4. None of these

61. The name enzyme was suggested in 1878 by the German physiologist choose one:

  1. Wilhelm Kuhne
  2. Koshland
  3. Fischer
  4. Paul Filder

62. Proteinaceous part of holoenzyme is choose one:

  1. Prosthetic group
  2. Apoenzyme
  3. Lecithin
  4. None of these

63. The “lock and key hypothesis” attempts to explain the mechanism of choose one:

  1. Vacuole formation
  2. Pinocytosis
  3. Sharing of electrons
  4. Enzyme specificity

64. An enzyme that hydrolyzes protein will not act upon starch. This fact is an indication that enzymes are choose one:

  1. Hydrolytic
  2. Specific
  3. Catalytic
  4. Synthetic

65. The site where enzyme catalyzed reaction takes place is called choose one:

  1. Active site
  2. Allosteric site
  3. Denatures site
  4. Dead site

66. What is a cofactor?

  1. Inorganic ions
  2. Organic molecules
  3. Both (A) and (B)
  4. None of the above

67. Mg+2 is an inorganic activator for the enzyme choose one:

  1. Phosophatase
  2. Carbonic anhydrase
  3. Enterokinase
  4. Amylase

68. Zn+2 is an inorganic activator for enzyme choose one:

  1. Carbonic anhydrase
  2. Phosophatase
  3. Chymotrypsin
  4. Maltase

69. Which antibiotic blocks the active site of an enzyme that many bacteria used to make cell-walls?

  1. Amphotericin
  2. Gentamicin
  3. Penicillin
  4. Cephalosporin

70. DDT and Parathion are inhibitors of key enzymes in choose one:

  1. Nervous system
  2. Respiratory system
  3. Digestive system
  4. Circulatory system

71. At high temperature the rate of enzyme action decreases because the increased heat choose one:

  1. Changes the pH of the system
  2. Alters the active site of the enzyme
  3. Neutralize acids and bases in the system
  4. Increases the concentration of enzymes

72. Which of the following enzymes would digest a fat?

  1. Sucrase
  2. Protease
  3. Ligase
  4. Lipase

73. In the lock and key model of enzyme action, the part of the enzyme that recognizes the substrate is known as the choose one:

  1. Enzyme-substrate complex
  2. Product
  3. Enzyme-product complex –
  4. Active site

74. What is a coenzyme?

  1. Inorganic ion
  2. Organic molecule
  3. Both (A) and (B)
  4. None of these

75. A certain enzyme will hydrolyze egg white but not starch. Which statement best explains this observation?

  1. Starch molecules are too large to be hydrolyzed
  2. Enzyme molecules are specific in their actions
  3. Egg white acts as a coenzyme for hydrolysis
  4. Starch is composed Of amino acids

76. At about 0°C, most enzymes are choose one:

  1. Inactive
  2. Active
  3. Destroyed
  4. Replicated

77. Vitamins are essential for the survival of organisms because vitamins usually function as choose one:

  1. Substrates
  2. Nucleic acids
  3. Co-enzymes
  4. Nucleosides

78. When a molecule binds to an area of an enzyme that is not the active site, and changes the shape of the enzyme so that it no longer can work, this is called choose one:

  1. Denaturation
  2. Competitive inhibition
  3. Noncompetitive inhibition
  4. Substrate delocation

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