Question

The respiratory substrate in photorespiration is-

• A. (A)Carbohydrate
• B. (B)Protein
• C. (C)Glycolic Acid
• D. (D)Glyoxylic Acid

Answer 1

The correct option is C

(C)Glycolic Acid

The correct option is (C)

Explanation of the correct option:

1. Photorespiration is a type of respiration that takes place in the presence of light between three organelles- chloroplast, peroxisomes, and mitochondria.
2. It occurs when the concentration of Carbon Dioxide(CO₂) is low and the concentration of Oxygen(O₂) is high in C₃ plants.
3. Photorespiration leads to the loss of Carbon Dioxide(CO₂) by the enzyme RuBisCo.
4. Its respiratory substrate is a 2-carbon compound glycolic acid.
5. Glycolic Acid is a 2-Carbon compound (C2).

Explanation of the incorrect options:

Option(A)

When carbohydrate is a respiratory substrate it is called floating respiration.

Option(B)

When protein is a respiratory substrate it is called protoplasmic respiration.

Option(D)

Glycolic Acid is oxidized inside the peroxisomes as Glyoxylic acid during photorespiration.

Final answer: The respiratory substrate in photorespiration is Glycolic Acid.