Plant-Physiologyphotosynthesis-4

Rubisco converts atmospheric carbon dioxide into organic molecules during photosynthesis.

It catalyses the first step of carbon dioxide fixation, where it combines CO2 with the RuBP leading to the formation of three carbon compounds.

Rubisco has both carboxylase and oxygenase activity.

Photorespiration occurs due to oxygenase activity of the enzyme RuBisco.

Photorespiration leads to decrease in the photosynthetic efficiency.

No ATP is produced during photorespiration. Additionally, some CO2 is release during the process. So it is a wasteful process.

In C3 plants the first stable product formed is a three-carbon compound known as 3 phosphoglyceric acid.

In C4 plants the first stable product formed is a four-carbon compound known as Oxaloacetic acid.

C4 plants show unique leaf anatomy known as Kranz anatomy.

There is spacial separation of the C4 and the C3 cycle in C4 plants.

C4 plants are photosynthetically more efficient and lack photorespiration.

Photorespiration is also known as C2 or Glycolate pathway.