MDCAT Biology MCQ #258

On a hot day, a plant closes its stomata, causing internal CO2 levels to drop. Which enzymatic activity of Rubisco then becomes dominant?

MDCAT Biology MCQ #258

  1. Question 1

    Q1. On a hot day, a plant closes its stomata, causing internal CO2 levels to drop. Which enzymatic activity of Rubisco then becomes dominant?

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

    Answer: Oxygenase

    Explanation: Rubisco binds oxygen when CO2 levels are low, leading to photorespiration. It acts as a carboxylase under normal high CO2 conditions.