Question

Is PEP carboxylase found in C3 plants?

Answer 1

C3 plants:

1. These plants use the Calvin pathway for the dark reactions (light-independent) to synthesize food using photosynthesis.
2. They synthesize a 3-carbon product, i.e., phosphoglyceric acid at the end of the reaction.
3. These plants can survive in temperate conditions and are found in abundance.

C4 plants:

1. C4 plants use the hatch and slack pathway for the dark reactions of photosynthesis.
2. C4 plants produce a 4-carbon carbohydrate at the end known as oxaloacetic acid.
3. C4 plants are found in tropical conditions in abundance.

PEP carboxylase:

1. PEP carboxylase is the first enzyme that helps in carbon fixation.
2. PEP carboxylase is present in the C3 (follow Calvin cycle in which initial assimilation of CO₂ produces 3 carbon molecule) plants where it produces 3-phosphoglycerate to replenish citric cycle intermediates and is also involved in the functioning of stomata.
3. Whereas in C4(Initial assimilation of CO₂ produces 4 carbon molecule) plants it is used for the conversion of initial CO₂ to oxaloacetate and then to phosphoenol pyruvate (PEP).
4. This PEP acts as a primary CO₂ acceptor which is later converted to oxaloacetic acid (OAA) by the enzymatic action of PEP carboxylase.
5. PEP carboxylase also helps in pH regulation and stomatal opening.