Multiple Choice Questions MCQs OF ENERGY AND ENZYME

Four options are given at the end of each statement. You should encircle one option from them.

  1. The chief source of energy is:a) Potential                (b) solar                      (c) Chemical            (d) Kinetic
    1. The energy present in food is:

    ,a) Potential               (b) solar                      (c) Kinetic                 (d) None

    1. Number of calories in kilocalories:

    a) 100                         (b) 500                        (c) 1000                    (d) 2000

    1. Degree of disorganization is:

    ,a) Enthalpy              (b) Entropy                (c) Activation            (d) None

    1. The lowering of the activation of energy of a reaction is called:

    (a) Enthalpy              (b) Entropy                (c) Activation            (d) Catalysis

    1. The optimum pH for enzyme is:

    a) 3                             (b) 2                           (c) 8                           (d) 4

    1. pepsin has an optimal pH

    a) 3                             (b) 2                            (c) 8                           (d) 4

    1. The optimum pH of trypsin is:

    a) 3                             (b) 2                            (c) 7                           (d) 9

    1. Which of the following is coenzyme?

    ,a) Mg                         (b) NAD                      (c) Ribozymes         (d) none

    Ans:

    1. (b) 2. (a) 3. (c) 4. (b) 5. (d) 6. (c) 7. (b) 8. (d) 9 (b)

    Fill in the blanks

    1. A plant can transform_____________ energy into chemical energy.
    2. The stored energy is called_____________ energy.
    3. The study of energy is called________________
    4. The commonly used unit for, measuring heat in an animal is the________________
    5. The measure of degree of disorganization is called___________
    6. The minimum amount of free energy to start a chemical reaction is called______________ energy.
    7. The reactions which absorb energy are called___________ reactions.
    8. The amount of reactant substance converted to product substance in agiven period of time is called reaction________
    9. An ______________ is a biological catalyst that can accelerate a specific chemical reaction by lowering the activation energy but remain unaltered in he process.
    10. The substrate binds with the enzyme. It changes the shape of enzyme.This phenomenon is called __________
    11. the metal ions which are loosely attached with the enzymes are called__________
    12. __________are non protein, organic molecules That participate in enzyme-catalyzed reactions.
    13. The coupling reaction in which synthesis of ATP molecule takes during movement of H+ across an H+ gradient is called__________

      Ans:

      1. solar                                 2. potential                           3. thermodynamics

      4. kilocalorie                       5. entropy                             6. activation

      7. endergonic                     8. rate                                     9. enzyme

      10. induced fit                    11. cofactors                        12. Coenzymes

      13. chemiosmosis

      Short Questions

      1. What is energy? Give its different forms.

      Ans: The capacity to do work is called energy. It has following forms: The heat from a furnace. The sound of a jet plane. The electric current that lights a bulb. The radioactivity in a heart pacemaker. The pull of a magnet.

      1. Differentiate between kinetic and potential energy.

      Ans: The energy – due to motion is called kinetic energy. For example, thundering waterfall. The stored energy is called potential energy.

      1. Define calorie.

      Ans: A calorie (c) is the amount of heat it takes to raise the temperature of 1 g (1 cc) of water 1°C from 14.5 to 15.5°C.

      1. Define first law of thermodynamics.

      Ans: It states that energy can neither be created nor destroyed, it can only be transformed from one form to another.

      1. Define second law of thermodynamics.

      Ans: It states that all objects in the universe tend to become more disordered and that the total amount of disorder in the universe is continually increasing.

      1. What is entropy?

      Ans: The measure of degree of disorganization is called entropy.

      1. What is activation of energy?

      Ans: The minimum amount of free energy to start a chemical reaction is called chemical energy.


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      1. Differentiate between exergonic and endergonic reaction.

      Ans: The reactions in which net release of energy take place is called exergonic reaction. The reactions which absorb energy are called endergonic reactions. The product contains more energy than the reactants.

      1. What is reaction rate?

      Ans: The amount of reactant substance converted to product substance in a given period of time is called reaction rate.

      1. What are catalysis and catalyst?

      Ans: The lowering of the activation of energy of a reaction is called catalysis.

      Any substance that performs catalysis is called a catalyst.

      1. Define an enzyme.

      Ans: An enzyme is a biological catalyst that can accelerate a specific chemical reaction by lowering the activation energy but remain unaltered in the process.

      1. What is meant by induced fit?

      Ans: The substrate binds with the enzyme. It changes the shape of enzyme. This phenomenon is called .induced fit.

      1. What is the affect of high Temperature on enzyme action? Ans: The bonds are too weak to hold the protein in proper position above 40° C. So enzyme can not maintain its shape. When proper shape is lost, the

      enzyme is destroyed. This loss of shape is called denaturation.              

      1. What are cofactors? Give examples.

      Ans: The metal ions which are loosely attached with the enzymes are called cofactors. These metal ions are Ca-2, Mg-2, Mn-2, Cu, and Zn-2.

      1. Define chemiosmosis.

      Ans: The coupling reaction in which synthesis of ATP, molecule takes during movement of H+ across an H+ gradient is called chemiosmosis.

      True/ False                 (For Punjab University only)

      Marks are True or False statement. Give correct statement if false

      Statement

      1. The lowering of the activation of energy of a reaction is called catalysis.
      2. The bonds are too weak to hold the protein in proper position .above 30° C.
      3. The coupling reaction in which synthesis of ATP molecule takes during movement of H across an H+ gradient is called chemiosmosis.
      4. Any substance that performs catalysis is called an inhibitor.
      5. The amount of excess energy is called free energy. •
      6. The capacity to do work is called energy.
      7. The measure of degree of disorganization is called enthalpy.
      8. The metal ions which are loosely attached with the enzymes are called cofactors.
      9. Any substance that performs catalysis is called a catalyst.Capture

       

          position above 40° C.
      1. The coupling reaction in which synthesis of ATP molecule takes during movement of Fl+ across an H+ gradient is called chemiosmosis.
      T  
      1. Any substance that performs catalysis is called an inhibitor,
      F Any substance that performs catalysis is called a catalyst.
      1. The amount of excess energy is called free energy.
      T  
      1. The capacity to do work is called energy.
      T  
      1. The measure of degree of disorganization is called enthalpy.
      F The measure of degree of disorganization is called entropy.
      1. The metal ions which are loosely attached with the enzymes are called cofactors.
      T  
      1. Any substance that performs catalysis is called a catalyst.
      T  

       

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