What is the fate of electrons from NADPH during the Calvin cycle?

1) They are added to 3PGA.
2) They are transferred to rubisco.
3) They are used to regenerate RuBP from G3P.
4) They are accepted by molecular oxygen, just like in cellular respiration.
5) They remain on NADPH to help drive the light reactions.

In the Calvin cycle, electrons from NADPH are used to reduce 3-PGA into G3P, which can contribute to forming glucose, while ATP helps regenerate RuBP for continuous cycle operation.Therefore, the correct option is 1) They are added to 3PGA.

Explanation:

The fate of electrons from NADPH during the Calvin cycle is specifically that they are used to convert 3-phosphoglycerate (3-PGA) into glyceraldehyde-3-phosphate (G3P). During the Calvin cycle, ATP and NADPH produced in the light reactions provide the energy and reducing power, respectively. The electrons from NADPH are ultimately used in the reduction phase of the Calvin cycle, where G3P is produced from the initial 3-PGA.

G3P is a crucial intermediate molecule that can be used to form glucose and other carbohydrates. Not all G3P molecules exit the cycle; most are recycled to regenerate RuBP (ribulose bisphosphate) with the help of ATP, thus preparing the system for the fixation of more CO₂. This final step is vital for the cycle to continue operating.