How Does Rubisco "Decide" Whether to Act as an Oxygenase

question 33

Multiple Choice

How does rubisco "decide" whether to act as an oxygenase or a carboxylase?

• A) Rubisco has 10 times more affinity for O₂ than CO₂; therefore, it favors O₂ fixation.
• B) If O₂ is relatively abundant, rubisco acts as a carboxylase.
• C) If O₂ predominates, rubisco fixes it and the Calvin-Benson cycle occurs.
• D) Photorespiration is more likely at low temperatures.
• E) As the ratio of CO₂ to O₂ falls in the leaf, the reaction of rubisco with O₂ is favored, and photorespiration proceeds.

---

Definitions:

Viruses

Microscopic infectious agents that can replicate only inside the living cells of an organism and are capable of causing diseases.

Chickenpox

A highly contagious viral infection characterized by an itchy rash and red spots or blisters all over the body.

Hepatitis

Inflammation of the liver usually caused by viruses or toxins.

Influenza

A contagious respiratory illness caused by influenza viruses, characterized by symptoms like fever, cough, and body aches.