Question

Complete this table.

Conditions	Flow of gases in Plants
Dark	1)
Dim	2)
Bright	3)

• A. 1) Oxygen taken in, carbon dioxide given out
  2) Carbon dioxide taken in, oxygen given out
  3) Neither gas is taken in or given out
• B. 1) Carbon dioxide taken in, oxygen given out
  2) Oxygen taken in, carbon dioxide given out
  3) Neither gas is taken in or given out
• C. 1) Neither gas is taken in or given out
  2) Carbon dioxide taken in, oxygen given out
  3) Oxygen taken in, carbon dioxide given out
• D. 1) Oxygen taken in, carbon dioxide given out
  2) Neither gas is taken in or given out
  3) Carbon dioxide taken in, oxygen given out

Answer 1

The correct option is D 1) Oxygen taken in, carbon dioxide given out

2) Neither gas is taken in or given out
3) Carbon dioxide taken in, oxygen given out
In dark light, respiration takes place but there is no photosynthesis. Hence oxygen is taken in for oxidation of respiratory substrate & carbon dioxide is given out as a product. In dim light, photosynthesis rate is equal to respiration rate. Hence oxygen released during photosynthesis is utilized during respiration & carbon dioxide released during respiration is utilized in photosynthesis. In bright light, photosynthesis rate is greater than respiration. Hence, carbon dioxide taken in, oxygen given out.