Photosynthesis:- Photoexcitation of Chlorophyll-a

 

Q.6:   Why Chl-a is called as essential pigment?               

Ans.: Essential pigment Chlorophyll–a:                  

a) It absorbs light independently and receives energy from non-essential pigments.

b) It shows photo-excitation due to absorption of light.

c) It converts solar energy into biologically usable form of energy i.e. ATP.

d) Chl-a is site of photolysis of water and releases oxygen.

e) It plays major role in the synthesis of NADPHZ; thus, it acts as reaction centre for photochemical phase or light reaction.

Q. 7: Write a note on photoexcitation of chl-a molecule:                 

Ans.: 1)  It is the first step of photosynthesis.

2) It explains expulsion of electron from chl-a molecule after absorption of energy.

3) Photoexcitation results in synthesis of ATP and NADPH2.

4) Photoexcitation brings about photolysis of water and releases free molecular oxygen.

5) The expelled electron, may or may not come back to its original positions.