Regulation of Calvin Cycle
The regulation of the Calvin Cycle takes place in the following way:
- The Calvin Cycle reactions do not occur at night or in the dark. The cycle’s enzymes are regulated by light, especially because the third step requires NADPH.
- Two regulatory systems control when the cycle starts or stops: the thioredoxin/ferredoxin system activates some enzymes, and the RuBisCo enzyme has its activation process involving an activase.
- The thioredoxin/ferredoxin system activates important enzymes in the cycle like glyceraldehyde-3-P dehydrogenase, fructose-1,6-bisphosphatase, and others. This occurs when light is present and ferredoxin, a protein, gets reduced in the thylakoid electron chain
- In the RuBisCo enzyme, a specific lysine amino acid needs to be carbamylated for activation. RuBisCo activase helps this process by enabling the binding of carbon dioxide. Magnesium ion, necessary for RuBisCo’s function, is released from the thylakoid lumen due to proton pumping from the electron flow.
- RuBisCo activase is activated by high ATP concentrations caused by phosphorylation in the stroma.
Calvin Cycle – Diagram, Stages, Functions and Equations
Calvin Cycle is the biochemical pathway in the plants responsible for synthesizing glucose using carbon dioxide and the energy obtained from sunlight. The Calvin cycle steps include carbon fixation, reduction, and regeneration. The final Calvin Cycle product is glyceraldehyde-3-phosphate (G3P) molecules. The cycle helps plants store energy and form sugar, supporting their growth and survival. This article covers the Calvin Cycle explained – definition, steps, diagram, and products.
Table of Content
- What is the Calvin Cycle?
- Calvin Cycle Diagram
- Steps of Calvin Cycle
- Calvin Cycle Equation
- Calvin Cycle Products
- Regulation of Calvin Cycle
- Functions of Calvin Cycle
- Importance of Calvin Cycle