9th class Biology

Chapter 6

Enzymes

Exercise solved Mcqs

 

1.      What is true about enzymes?

a)      They make biochemical reactions to proceed spontaneously

b)      They lower the activation energy of a reaction

c)      They are not very specific in their choice of substrates

d)      They are needed in large quantities

2.      To what category of molecules to enzymes belong?

a)      Carbohydrates

b)      Lipids

c)      Nucleic acids

d)      Proteins

3. What is true about cofactors?

a)      Break hydrogen bond in protein

b)      Help facilitate enzymes activity

c)      Increase activation energy

d)      Are composed of proteins

4. Prosthetic groups are;

a)      Required by all enzymes

b)      Loosely attached with enzymes

c)      Proteins in nature

d)      Tightly bound to enzyme

5. When we add more substrate to an already occurring enzymatic reaction and there is no increase in the rate of reaction, what would you predict?

a)      All active site have been occupied by substrate molecules

b)      The enzyme molecules have denature

c)      More substrate acted as inhibitor

d)      More substrate has distributed the pH of the medium

 

9th class Biology

Chapter 7

Bioenergetics

Exercise solved Mcqs

1.      1. Which of the following steps of respiration, CO2 is produced?

a.      Glycolysis

  1. Krebs cycle
  2. Electron transport chain
  3. All of these

2.   2.    Oxygen takes part in aerobic respiration in;

a)      Glycolysis

b)      Link step between Glycolysis and Krebs cycle

c)      Krebs cycle

d)      Electron transport chain

 3. When a plant was kept in darkness for many days its leaves turned yellow. why?

a)      Leaves could not get oxygen and so there was no photosynthesis

b)      Leaves could not get light and so there was no respiration

c)      Leaves could not get oxygen and so there was no respiration

d)      Leaves could not get light and so there was no  photosynthesis

4.From which Bonds of ATP molecule energy is taken?

a)      P-P bonds

b)      C-H bonds

c)      C-N bonds

d)      C-O bonds

5. In which component of leaf cells, chlorophyll is present?

a)      Stroma

b)      Thylakoids

c)      Plasma membrane

d)      cytoplasm

6.     6.  Which of these can enter into krebs cycle?

a)      Glucose

b)      Pyruvic acid

c)      Citric acid

d)      Acetyl Co-A

7.      7. When we work hard we suffer from muscle fatigue because muscle cells;

a)      Carry out aerobic respiration at faster rate and so are tired

b)      Carry out anaerobic respiration and so accumulate more CO2

c)      Carry out anaerobic respiration and so accumulate lactic acid

d)      Carry out aerobic respiration and so accumulate lactic acid

8.      8. Who many molecules of CO2 produced when krebs cycle operated once?

a)      01

b)      02

c)      03

d)      04

9.      9. In which of the following metabolic processes, oxidation as well as reduction of molecule occur?

a)      Photosynthesis

b)      Respiration

c)      Both

d)      None of these

       10.   Chlorophyll pigment absorb maximum light in wavelengths of;

a)      Green and blue

b)      Green and red

c)      Green only

d)      Red and blue

 

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