Question

Match the column-1 with column II and choose the correct answer using the codes given below.

Column I		Column II
A	Emerson effect	I	$C_4$ cycle
B	Hill reaction	II	Photolysis
C	Calvin cycle	III	$C_3$ cycle
D	Hatch & Slack cycle	IV	Photosystem I & II

• A. A - I; B - II; C - III; D - IV
• B. A - I; B - III; C - IV; D - I
• C. A - III; B - IV; C - I; D - II
• D. A - IV; B - II; C - III; D - I

Answer 1

Answer: (D)

A: Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to light of wavelength $670\, nm$ (far red light) and $700\, nm$ (red light). It involves both photosystem I and II.
B: Hills reaction (or photolysis of water) is the lightdependent transfer of electrons by chloroplasts in photosynthesis that results in the cleavage of water molecules and liberation of oxygen. Hill reaction was proposed by Robert Hill.
C. Calvin cycle (also called $C _3$ pathway) is the set of chemical reactions that take place in stroma of the chloroplasts during photosynthesis. The cycle is light independent because it takes place after the energy has been captured from sunlight.
D: Hatch & Slack cycle (also known as $C _4$ pathway) is a metabolic cycle involved in the non-light-requiring phase of photosynthesis in certain plants having specific metabolic and anatomical modifications in their mesophyll and bundle sheath cells which facilitate the temporary fixation of carbon dioxide $\left( CO _2\right)$ into four-carbon organic acid. These acids are next broken down to three-carbon organic acids along with $CO _2$ in bundle sheath cells, where this unbound $CO _2$ is then fixed into carbohydrates in a normal Calvin cycle pathway.