Question

In sugarcane plant $^{14}CO_2$ is fixed in malic acid, in which the enzyme that fixes $CO_2$ is:

• A. Ribulose biphosphate carboxylase
• B. Phosphoenol pyruvic acid carboxylase
• C. Ribulose phosphate kinase
• D. Fructose phosphatase

Answer 1

Answer: (B)

Phosphoenol pyruvic acid carboxylase

Answer 2

In the sugarcane plant, Phosphoenol pyruvic acid carboxylase (PEP carboxylase) is the enzyme responsible for fixing $CO_2$ to form malic acid during a process called Crassulacean Acid Metabolism (CAM). This enzyme is crucial for $CO_2$ fixation in plants that use the CAM photosynthesis pathway, which includes many succulent plants like sugarcane.

So, the correct option is (B): Phosphoenol pyruvic acid carboxylase