Question

Why c2 cycle is absent in c4 plants

Answer 1

C2 cycle is absent in C4 plants because they have well-specialised mechanism for Carboxylation and to increase the inner concentration of CO2. Hence, decreasing the chances of binding of Oxygen. Hence, photorespiration or C2 cycle is absent in C4 plants.

Hope it helps!☺️

Answer 2

Answer:

Because the C4 plants have a mechanism of maintaining high CO₂ at the enzyme site

Explanation:

• Photorespiration occurs due to the oxygenase activity of the RUBISCO enzyme.

• When the concentration of O₂ is high, the oxygenase site of RUBISCO gets activated. It binds to oxygen and carries out photorespiration.

• In C₄ plants, they have a special mechanism that increases the CO₂ concentration at the enzyme site. and due to the kranz anatomy.

• The leaf mesophyll cells lack the enzyme.

• The malic acid from the mesophyll cell undergoes break down in the bundle sheath cell to release carbon dioxide. This leads to increased intracellular CO₂ concentration.

• This ensures that the enzyme Rubisco function as a carboxylase minimizing the oxygenase activity.

Hence C₄ plants lack the C₂ cycle.