MDCAT Biology MCQ #407

During a hot, dry afternoon, a C3 plant closes its stomata to conserve water. Which enzymatic activity of Rubisco increases as a result?

MDCAT Biology MCQ #407

  1. Question 1

    Q1. During a hot, dry afternoon, a C3 plant closes its stomata to conserve water. Which enzymatic activity of Rubisco increases as a result?

    • A) Carboxylase
    • B) Oxygenase
    • C) Dehydrogenase
    • D) Reductase

    Answer: Oxygenase

    Explanation: Rubisco acts as an oxygenase when CO2 is low, leading to photorespiration. Carboxylase activity is wrong because it happens only when CO2 is abundant.