Question

The compounds produced when RuBP reacts with O$_2$ are

• A. 3-phosphoglyceric acid
• B. G-3-P and DHAP
• C. Phosphoglycerate and Phosphoglycolate
• D. Phosphoglycolate and Glyceraldehyde-3-P

Hint:

When RuBP reacts with O$_2$, it leads to photorespiration and forms one phosphoglycerate and one phosphoglycolate molecule.

Answer 1

The Correct Option is C

When RuBP (Ribulose-1,5-bisphosphate) reacts with oxygen (O₂) instead of carbon dioxide (CO₂), a process called photorespiration occurs. This oxygenation reaction is catalyzed by the enzyme Rubisco.
During this reaction:
- One molecule of RuBP reacts with O₂
- This produces one molecule of 3-phosphoglycerate (PGA) and one molecule of phosphoglycolate
This is in contrast to the normal carboxylation reaction (with CO₂), which produces two molecules of 3-phosphoglycerate.
Therefore, the correct products of the reaction between RuBP and O₂ are:
- Phosphoglycerate
- Phosphoglycolate

Answer 2

The compounds produced when RuBP reacts with O₂ are:

When Ribulose-1,5-bisphosphate (RuBP) reacts with oxygen (O₂) during photorespiration, it leads to the formation of two compounds:

1. Phosphoglycerate (3-PGA): This is a 3-carbon compound that also forms during the normal Calvin cycle when RuBP reacts with CO₂.

2. Phosphoglycolate: This is a 2-carbon compound formed specifically due to the oxygenation reaction. It cannot be directly used in the Calvin cycle and must be recycled through photorespiration.

Thus, RuBP reacts with oxygen to produce phosphoglycerate and phosphoglycolate.

Correct Answer: Phosphoglycerate and Phosphoglycolate