Which of the following is true regarding CO₂ fixation in plants? A) CAM plants work by storing carbon dioxide at night in the form of oxaloacetate B) The RUBISCO enzyme has a higher affinity for oxygen than for CO₂, making it very difficult to effectively fix CO₂ C) At high temperatures, C4 plants are more efficient than C3 plants because they are able to fix CO₂ with minimal photorespiration D) The RUBISCO enzyme contains a Mg²⁺ that acts as a Lewis base, binding to CO₂ and making it more susceptible to nucleophilic attack E) None of the above are true

Question

Quizplus · Accepted Answer

C4 plants are able to fix CO2 more efficiently at high temperatures due to their ability to minimize photorespiration by spatially separating the initial uptake of CO2 from the rest of the Calvin cycle. This allows for more efficient use of energy and resources in the plant. CAM plants also store CO2 at night, but they do so by fixing it into oxaloacetate, not by directly fixing CO2 as in C4 and C3 plants. The RUBISCO enzyme does indeed have a higher affinity for oxygen than for CO2, which can lead to photorespiration in C3 plants, but this is not directly related to CO₂ fixation in plants. The Mg²⁺ in RUBISCO does play a role in binding and facilitating the fixation of CO2, but the statement about it binding to CO2 and making it more susceptible to nucleophilic attack is not accurate.

Which of the Following Is True Regarding CO2 Fixation in Plants

Which of the Following Is True Regarding CO₂ Fixation in Plants