Question

In CAM plants, CO2 is bonded to ________ to form _______.

(1) PEP, oxaloacetate
(2) oxaloacetate, PEP
(3) RuBP, PGA
(4) oxaloacetate, citrate
(5) citrate, oxaloacetate

Answer 1

In CAM plants, carbon dioxide is bonded to PEP to form oxaloacetate, which is enabled by the enzyme PEP carboxylase.

Step-by-step explanation:

In CAM (Crassulacean Acid Metabolism) plants, CO₂ is bonded to PEP (phosphoenolpyruvate) to form oxaloacetate. This is a two-step process where first, PEP carboxylase catalyzes the fixation of CO₂ to PEP, resulting in oxaloacetate, a four-carbon compound. This process differs from the carbon fixation in C3 plants, where RuBisCO catalyzes the reaction between CO₂ and RuBP (ribulose bisphosphate) to form 3-PGA (3-phospho glyceric acid). The correct answer to the student's question is option (1) PEP, oxaloacetate.