CO₂ fixation is one of the most critical reactions on earth. Which of the following are elements of the reaction catalyzed by the RUBISCO enzyme? A) Mg²⁺ acts as a Lewis acid, binding to CO₂ and making it more susceptible to nucleophilic attack B) The 6-carbon enzyme-bound intermediate that forms is split into 2 molecules of 3-phosphoglycerate C) Biotin is attached to a Lys residue in the active site and serves a critical role in the activation of CO₂ D) ATP is required for the activation of CO2 prior to its reaction with ribulose-1,5-bisphosphate E) Both a and b occur

Question

Quizplus · Accepted Answer

A) Mg^2+ acts as a Lewis acid, binding to CO_2 and making it more reactive, facilitating its fixation. B) The 6-carbon intermediate indeed splits into two molecules of 3-phosphoglycerate in the Calvin cycle. C) is incorrect because biotin is not involved in the RUBISCO-catalyzed reaction; it's involved in carboxylation reactions but not in this context. D) is incorrect because ATP is not directly used in the reaction catalyzed by RUBISCO; ATP is used in other steps of the Calvin cycle.

CO2 Fixation Is One of the Most Critical Reactions on Earth

CO₂ Fixation Is One of the Most Critical Reactions on Earth