MDCAT Biology MCQ #503

In the first step of the Calvin cycle, carbon dioxide is attached to a five-carbon sugar. Which enzyme is responsible for this fixation?

MDCAT Biology MCQ #503

  1. Question 1

    Q1. In the first step of the Calvin cycle, carbon dioxide is attached to a five-carbon sugar. Which enzyme is responsible for this fixation?

    • A) NADP reductase
    • B) Rubisco
    • C) PEP carboxylase
    • D) ATP synthase

    Answer: Rubisco

    Explanation: Rubisco catalyzes the fixation of CO2 to RuBP, forming an unstable 6-carbon intermediate that splits into 3-phosphoglycerate.