Which of the following statements is correct?

1.	Photorespiration is useful process.
2.	C4 plants are more efficient than C3 plants.
3.	C4 plants are less efficient than C3 plants.
4.	Photorespiration is absent in C3 plants but present in C4 plants.

Photorespiration shows formation of 

1. sugar but not ATP

2. ATP but not sugar

3. both ATP and sugar

4. neither ATP nor sugar.

Kranz anatomy is usually associated with 

(1) C₃ plants

(2) C₄ plants

(3) CAM plants

(4) C₃-C₄ intermediate plants.

C₄ plants have better productivity because 

(1) C₄ plants absorb more light

(2) C₄ plants absorb more CO₂

(3) C₄ plants does not carry photorespiration

(4) C₄ plants have more amount of RuBisCO.

The first carbon dioxide fixation product of C₄ plant is 

(1) Oxaloacetic acid

(2) ribulose biphosphate

(3) phosphoenol pyruvate

(4) phosphoglyceric acid.

Carbon dioxide is necessary for photosynthesis. The chemical used to remove this gas most effectively from entering a control apparatus is 

1. calcium oxide

2. distilled water

3. potassium hydroxide solution

4. sodium carbonate.

Photosynthesis in C4 plants is relatively less limited by atmospheric CO₂ levels because 

(1) there is effective pumping of CO₂ into bundle sheath cells

(2) RuBisCO in C4 plants has higher affinity for CO₂

(3) six carbon acids are the primary initial CO₂ fixation products

(4) the primary fixation of CO₂ is mediated via PEP carboxylase.

The chemiosmotic coupling hypotheisis of oxidative phosphorylation proposes that adenosine triphosphate (ATP) is formed because

(1) a proton gradient forms across the inner mitochondrial membrane. 

(2) There is a change in the permeability of the inner mitochondrial membrane towards adenosine diphosphate (ADP).

(3) high energy bonds are formed in mitochondrial proteins

(4) ADP is pumped out of the matrix into the intermembrane space.

Which of the following is incorrect about the light reactions of photosynthesis?

1. P₆₈₀ and P₇₀₀ are the reaction centres of PS-I and PS-II respectively

2. Light energy provides energy for the photolysis of water through excitation of the reaction centre of PS-II

3. NADPH is not produced in cyclic electrons transport in light reactions

4. Reactions of the two photosystems are needed for the reduction of NADP

In blue-green algae, photosystem- II contains important pigment concerned with photolysis of water. It is a

(1) phycocyanin           

(2) cytochrome-c

(3) chlorophyll -$b$         

(4) $\beta$-carotene