CO₂ Fixation Is One of the Most Critical Reactions on Earth

question 39

Multiple Choice

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

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