HBSE Class 12 Biology Enzymes Multiple Choice Questions

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Enzymes Multiple Choice Question and Answers

Question 1. The enzymes that break up starch into sugar are called:

  1. Hydrolase
  2. Amylase
  3. Lipase
  4. Nucleases.

Answer: 2. Amylase

Question 2. Enzymes are named after their substrate by adding a suffix:

  1. – In
  2. – Ase
  3. – Os
  4. – Sin.

Answer: 2. – Ase

Question 3. Apoenzyme is :

  1. Protein
  2. Carbohydrates
  3. Vitamin
  4. Amino acid.

Answer: 1. Protein

Question 4. Co-enzyme is :

  1. Always a protein
  2. Always a vitamin
  3. Often a vitamin
  4. Often a protein

Answer: 3. Often a vitamin

Question 5. The rate of most of the enzyme-catalyzed reactions changes with pH. As the pH increases, this rate:

  1. Reaches a maximum then decreases
  2. Reaches a minimum then decreases
  3. Increases
  4. Decreases.

Answer: 1. Reaches a maximum then decreases

Question 6. Co-enzymes can function :

  1. In association with an apoenzyme
  2. Independently of the apoenzyme
  3. In association with vitamin
  4. In association with a protein.

Answer: 1. In association with an apoenzyme

carbohydrates questions

Question 7. The enzymes which break up nucleic acids into nucleotides are called:

  1. Nucleases
  2. Amylases
  3. Lipase
  4. Protease.

Answer: 1. Nucleases

Question 8. Which mineral element is essential for the activity of enzyme nitrate reductase:

  1. Molybdenum
  2. Iron
  3. Zinc
  4. Calcium

Answer: 1. Molybdenum

Question 9. Most vitamins function as :

  1. Holoenzyme
  2. Enzymes
  3. Hormones
  4. Co-enzymes

Answer: 4. Co-enzymes

Enzymes Class 12 HBSE Biology Notes

Question 10. Stoppage of the biochemical process by the product of a step is known as:

  1. Negative inhibition
  2. Endproductinhibition
  3. Feedback inhibition
  4. All of the above

Answer: 4. All of the above

Question 11. Which of the following is the best evidence for the lock and key theory of enzyme action?

  1. A11 isolated enzymes have been identified as proteins
  2. Compounds similar in structure to the substrate inhibit the reaction
  3. Enzymes are found in living organisms and speed up certain reactions
  4. Enzymes determine the direction of a reaction

Answer: 2. Compounds similar in structure to the substrate inhibits the reaction

Question 12. Enzymes generally have :

  1. Same pH and temperature options
  2. Same pH but different temperature options
  3. Different pH but same temperature optima
  4. Different pH and different temperature optima

Answer: 3. Different pH but same temperature optima

Question 13. The term feedback refers to

  1. The effect of substrate on the rate of enzymatic reaction
  2. The effect of end product on the rate of enzymatic reaction
  3. The effect of enzyme concentration or its rate of reaction
  4. The effect of an external compound on the rate of enzymatic reaction.

Answer: 2. The effect of the end product on the rate of enzymatic reaction

Classification Of Enzymes With Examples Class 12

Question 14. Near the freezing point, an enzyme is :

  1. Killed
  2. Slightliz activated
  3. Inactivated
  4. Unaltected

Answer: 3. Inactivated

Question 15. Which of the following statements is true about enzymes?

  1. Is altered permanently in the reaction it catalyses
  2. Lowers the energy of activation of a reaction
  3. Makes the equilibrium n-lore favorable for the organism
  4. Lowers the energy of the product and increases the energy of the reactant.

Answer: 2. Lowers the energy of activation of a reaction

protein parts of enzyme is known as 

Question 16. Enzymes, vitamins, and hormones have one thing in common:

  1. Au is synthesized in organisms
  2. All are proteins
  3. Al1 aids in regulating metabolism
  4. All enhance oxidative metabolism.

Answer: 3. Al1 aids in regulating metabolism

Question 17. Which energy is needed to digest food reserves in castor seeds?

  1. Lipase
  2. Proteases
  3. Amylase
  4. Lactase.

Answer: 1. Lipase

Factors Affecting Enzyme Activity Class 12 HBSE

Question 18. Which of the following is the best evidence for the template theory of enzyme action?

  1. Compounds similar in structure to the substrate inhibit the reaction
  2. Enzymes speed up the reactions by definite amounts
  3. Enzymes determine the direction of a reaction
  4. Enzymes are found in living organisms and increase the rate of certain reactions.

Answer: 1. Compounds similar in structure to the substrate inhibits the reaction

Question 19. Nitrate reductase enzyme forms :

  1. N2
  2. Amino acids
  3. NO¯²
  4. NO‾³

Answer: 3. NO-2

Question 20. In plants enzymes are present :

  1. Only in flowers
  2. Only in leaves
  3. In all the living cells of the plant body
  4. Only in storage organ.

Answer: 3. In a1l the living cells of the plant body

Question 21. Which of the following lacks enzymes?

  1. Algae
  2. Fungi
  3. Bacteria
  4. Virus.

Answer: 4. Virus.

Question 22. In the cell, digestive enzymes are mostly in :

  1. Ysosornes
  2. Cel1wal1
  3. Ribosomes
  4. Chromosome.

Answer: 1. Ysosornes

Enzyme Action Mechanism Class 12 HBSE

Question 23. Which of the following is iron-porphyrin complex?

  1. Cytochrome
  2. Fad
  3. Co-a
  4. Nad

Answer: 1. Cytochrome

Question 24. Fad or fmn is a co-enzyme. Which vitamin is incorporated into its structure?

  1. Vitamin c
  2. Vitamin B1
  3. Vitamin B6
  4. Vitamin B2

Answer: 4. Vitamin B.

Question 25. The ratio of the enzyme to the substrate molecule can be as high as:

  1. 1: 1000
  2. 1: 100,000
  3. 1: 1000,000
  4. 1: 50,000.

Answer: 3. 1: 1000,000

questions on carbohydrates

Question 26. Lock and key hypothesis to explain the action of enzymatic action was given by :

  1. Kogl
  2. Fischer
  3. Miller
  4. Lederberg and Tatum.

Answer: 2. Fischer

Question 27. Enzymes with the same function and different molecular structures are called:

  1. Isomerases
  2. Zymases
  3. Isoenzymes
  4. Coenzymes.

Answer: 3. Isoenzymes

Importance Of Enzymes In Metabolism Class 12

Question 28. The enzyme that removes the hydrogen from a substrate is:

  1. Decarboxylase
  2. Dehydrogenase
  3. Protease
  4. Lipase.

Answer: 2. Dehydrogenase

Michaelis-Menten Equation Derivation Class 12

Question 29. Which of the following is not true for enzymes?

  1. Colloidal nature
  2. Used up in the biochemical reaction
  3. Affected by the change in temperature
  4. Lowers the activation energy.

Answer: 2. Used up in the biochemical reaction

Question 30. Zyrnogen is defined as :

  1. An enzyme inhibitor
  2. Highly reactive state of the enzyme
  3. An inactive proenzyme.
  4. Complex formed of enzyme and substrate

Answer: 3. An inactive proenzyme.

Question 31. Which of the following enzymes would change glucose-6 phosphate to glucose 1-phosphate?

  1. Transferase
  2. Isomerase
  3. Lyases
  4. Glucose phosphatases.

Answer: 2. Isomerase

Difference Between Enzyme And Catalyst Class 12

Question 32. Maximum enzyme activity is observed at :

  1. Acidic ph
  2. Neutral ph
  3. Basic ph
  4. Optimum ph.

Answer: 4. Optimum ph.

Question 33. Conversion of pepsinogen into pepsin is :

  1. Intramolecular rearrangement
  2. Breaking of hydrogen bonds
  3. Covalent modifications
  4. Polymerization

Answer: 3. Covalent modifications

Applications Of Enzymes In Biotechnology Class 12

Question 34. The following reaction is characteristic of what type of enzyme?

  1. Peroxidases
  2. Catalases
  3. Dehydrogenases
  4. Copper-containing oxidases.

Answer: 1. Peroxidases

Question 35. Number of substrate molecules changed per minute by a molecule of the enzyme is called:

  1. Reaction index
  2. Turn over number
  3. Deficiency number
  4. Optimum number.

Answer: 2. Turn over number

Question 36. During the enzyme action:

  1. The value of k is low
  2. The value of k1 is low
  3. The value of k- is high
  4. The value of k, is high.

Answer: 2. Value of k1 is low

Enzyme Activity Graph Explanation Class 12 HBSE

Question 37. Oxidative enzymes mostly occur in :

  1. Lysosomes
  2. Mitochondria
  3. Ribosomes
  4. Golgi bodies.

Answer: 2. Mitochondria

Question 38. The substrate concentration at which half of the maximum velocity is achieved is termed :

  1. Sumner’s constant
  2. Michaelis constant
  3. Buchner constant
  4. Fischer constant.

Answer: 2. Michaelis constant

Enzyme Inhibition Types Class 12 HBSE

Question 39. An enzyme brings about :

  1. Reduction in activation energy
  2. Increase in reaction time
  3. Increase in activation energy
  4. All the above.

Answer: 1. Reduction in activation energy

Question 40. Enzymes exist in the cells as :

  1. Solid
  2. Crystals
  3. Colloid
  4. None of the above.

Answer: 3. Colloid

 

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