Question

1. Maltose is made of 2 glucose molecules. If one molecule of maltose is made in a plant cell, how many times must CO2 go through the Calvin cycle? How many ATP and NADPH are needed? Please explain in detail.

Answer 1

Answer: If one molecule of maltose is made in a plant cell, 12 times CO2 must go through the Calvin cycle and 36 molecules ATP and 24 molecules NADPH are needed.
Explanation- During Calvin Cycle, 3 molecules of CO2 with the help of 9 molecules of ATP and 6 molecules of NADPH, produces 6 molecules of Glyceraldehyde-3-Phosphate(GA3P). 5 molecules of GA3P undergoes regeneration of RuBP step. 1 molecules of GA3P produces 1/2 molecules of glucose molecule during light reaction of photosynthesis.
Over all reaction is of Calvin Cycle is:
3 CO2 + 6 NADPH + 5 H2O + 9 ATP = GA3P +2H+ + 6 NADP+ + 9 ADP + 8 Pi
Only one CO2 molecule is incorporated at a time, so the cycle must be completed 3 times to produce a single 3C GA3P molecule, and 6 times to produce a 6C glucose molecule with the help of 18 molecules of ATP and 12 molecules of NADPH.
For Production of Moltose(made up with 2 glucose molecules) cycle must be completed 12 times. ATP needed 36 molecules and NADPH needed 24 molecules.