Ribulose bisphosphate (RuBP)

Definition

Ribulose bisphosphate (RuBP) is a five-carbon sugar involved in the Calvin cycle of photosynthesis. It acts as a substrate for the enzyme RuBisCO to fix carbon dioxide into organic molecules.

5 Must Know Facts For Your Next Test

1. RuBP is regenerated in each turn of the Calvin cycle, allowing the cycle to continue.
2. In the first step of the Calvin cycle, RuBP combines with CO2 to form two molecules of 3-phosphoglycerate.
3. The enzyme RuBisCO catalyzes the reaction between RuBP and CO2.
4. RuBP has two phosphate groups attached to its structure.
5. Deficiencies or inefficiencies in RuBP regeneration can limit the rate of photosynthesis.

Review Questions

Related terms

RuBisCO:

An enzyme that catalyzes the fixation of carbon dioxide with ribulose bisphosphate during photosynthesis.

Calvin Cycle:

A series of biochemical reactions that take place in the chloroplasts during photosynthesis, aiming to produce glucose from carbon dioxide and water.

3-Phosphoglycerate: A three-carbon molecule formed when CO2 reacts with ribulose bisphosphate during photosynthesis.