What are the steps in Calvin cycle?

Answer 1

1. Carbon Fixation

Step 1: 3 CO2 comes in and an enzyme called rubisco hopefully (when I say hopefully, I mean that because it might catalyze oxygen instead of carbon, which is bad) catalyzes carbon.

Step 2: The carbon is turned into RuBP (a 6 carbon), which is unstable, so it instantly turns into two of 3-PG (a 3 carbon). There are 6 of these.

2. Reduction

Step 3: The 3-PG get a phosphate each from ATP, which then turns into ADP. The 3-PG now become 3-biphosphoglycerate. There are 6 of these.

Step 4: The 3-biphosphoglycerate each get an hydrogen ion (H+) from NADPH, which then turns into NADP+.

Step 5: The molecule then and there loose a phosphate group, which goes back to restoring the ADP into ATP. The resulting molecule is called G3P, which is final goal for the Calvin Cycle. There are 6 G3P molecules.

3. Regeneration

Step 6: As I mentioned earlier, G3P is the main goal of the Calvin cycle, so only one out of the 6 are used for as organic compounds, whereas the rest go back in the cycle.

Step 7: The 5 G3P molecules that go back to the cycle are rearranged to become the molecule RuBP (ribulose biphosphate) and go back to step 2.

Answer 2

The three steps of the Calvin cycle are carbon fixation, reduction and regeneration.

1) Carbon fixation

In this step, an enzyme called rubisco attaches carbon dioxide (CO2) to a sugar called ribulose biphosphate (RuBP). This reaction creates a very unstable intermediate which immediately splits in half, forming two molecules of 3-phosphoglycerate.

2) Reduction

Here, ATP gives those 3-phosphoglycerate molecules an additional phosphate group, converting them into 1,3-biphosphoglycerate. NADPH reduces this molecule, which incidentally also loses a phosphate group, and it becomes glyceraldehyde-3-phosphate (G3P).

3) Regeneration

Lastly, using ATP and some of the G3P molecules produced during reduction, the Calvin cycle recreates ribulose biphosphate through a series of complex reactions, which begins the cycle anew.