Calvin Cycle
What is it?
The process plants go through to turn the carbon dioxide (CO2) they receive into the sugars they need to survive.
Every living thing depends on the Calvin Cycle
Plants - for food and energy
Herbivores - indirectly because they eat plants for food
Carnivores - for energy, food and nutrients through the herbivores it eats
Discovered by Dr. Melvin Calvin in 1957
Three Main Stages:
Fixation
The fixation of carbon dioxide
Begins with 3CO2
The enzyme Rubisco helps catalyze the reaction with Ribulose 1,5 bisphosphate (RuBP)
This forms an unstable compound
Which ends up being 6 molecules of 3-phosphoglycerate (PGA)
The technical equation is as follows:
3 atoms from 3CO2 + 15 atoms from 3RuBP = 18 atoms in 3 atoms of 3-PGA
Reduction
The reduction of 3-phosphoglycerate to G3P
The 6 3-PGA receives 1 ATP and 1 NADPH
This reaction changes it to 6 glyceraldehyde-3-phosphate (G3P)
A G3P is half of a glucose
Regeneration
The regeneration of RuBP from G3P
One G3P leaves the cycle to be used for food, energy or storage
The remaining 5 G3P are rearranged again with ATP to regenerate the RuBP
This starts the cycle all over again
A bit more information:
Each turn of the cycle produces 1 G3P so the cycle has to run 6 times before a 6C carbohydrate molecule can be made
The sugars made are used for glucose (food), starch (energy), and cellulose (structure)
The Calvin Cycle does not require sunlight energy to work
By: Jaime Blokker 2021