Which of the following statements about phytochrome is true?

1.	Pr absorbs yellow light and becomes Pfr
2.	Pr absorbs red light and becomes Pfr
3.	Pfr absorbs red light and becomes Pr
4.	Pfr absorbs yellow light and becomes Pr .

Blackman's law is related to 

1. respiration

2. transpiration

3. root pressure

4. photosynthesis.

Who discovered photophosphorylation?

1. Arnon et. al.

2. Von Mayer

3. Clavin et.al.

4. Hill

Photosynthetic bacteria do not contain

The photorespiratory carbon-oxidation cycle involves the interaction of

1. chloroplast

2. mitochordria

3. peroxisomes

4. all of these.

Photorespiration in C₃ plants starts from:

(1) phosphoglycerate

(2) phosphoglycolate

(3) Glycerate

(4) glycine.

Hill reaction occurs in:

1. high altitude plants

2. total darkness

3. absence of water

4. presence of ferricyanide

Which one of the following categories of organisms do not evolve oxygen during photosynthesis?

Which of the following is the characteristic of PS-I?

Cyclic photophosphorylation invloves