Crops such as tomatoes and bell pepper, allowed to grow in a carbon dioxide rich environment, show higher yields because:

1. They show an increased rate of photosynthesis at higher carbon dioxide concentrations.

2. They can respond to high carbon dioxide conditions even in low light conditions.

3. They show C₄ pathway for carbon fixation at high carbon dioxide is the limiting factor in such plants. 

4. Only carbon dioxide is the limiting factor in such plants.

At about what percentage of the full sunlight does light saturation occurs in photosynthesis?

1. 10

2. 25

3. 70

4. 95

Suppose the interoir of the thylakoids of isolated chloroplasts and then transferred in the dark to a pH 8 solution. What would be likely to happen?

(1) The isolated chloroplasts will make ATP

(2) The Clavin cycle will be activated.

(3) The cyclic photophosphorylation will occur

(4) Isolated chloroplasts will generate oxygen gas

Consider the following two statements:

I. Except for plants in shade or in dense forests, light is rarely a limiting factor in nature for photosynthesis.

II. Light saturation occurs at 50% of the full sunlight.

1. Both statements are correct and II explains I

2. Both statements are incorrect

3. I is correct and II is incorrect

4. I is incorrect and II is correct

For assimilation of one CO₂ molecule via photosynthesis, the energy required in form of ATP and NADPH₂ are:

(1) 2 ATP and 2 NADPH₂ 

(2) 5 ATP and 3 NADPH₂ 

(3) 3 ATP and 2 NADPH₂ 

(4) 18 ATP and 12 NADPH_2. 

Phosphoenol pyruvate (PEP) is the primary CO₂ acceptor in

(1) C₃ -plants 

(2) C₄ -plants

(3) C₂ -plants

(4) C₃ and C₄ -plants

With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct?

(1) Light saturation for CO₂-fixation occurs at 10% of full sunlight.

(2) Increasing atmospheric CO₂ concentration upto 0.05% can enhance the CO₂-fixation rate

(3) C₃ plants respond to higher temperature with enhanced photosynthesis, while C₄ plants have a much lower temperature optimum.

(4) Tomato is a greenhouse crop, which can be grown in a CO₂-enriched atmosphere for higher yield. 

Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using the following options. 

1. Both process can happen together because the diffusion coefficient of water and CO₂ is different. 

2. The above processes happen only during night time

3. One process occurs during the day time and the other night

4. Both processes cannot happen simultaneously

A plant in your garden avoids photorespiratory losses, has improved water use efficiency, shows high rates of photosynthesis at high temperatures and has improved efficiency of nitrogen utilization. In which of the following physiological groups would you assign this plant?

(1) C₄

(2) CAM

(3) Nitrogen-fixer

(4) C₃

Emerson's enhancement effect and red drop have been instrumental in the discovery of 

(1) two photosystems operating simultaneously

(2) photophosphorylation and cyclic electron transport. 

(3) Oxidative phosphorylation

(4) photophosphorylation and non-cyclic electron transport