Question

Photorespiration can happen during (Please select right answer one ---> (The light reactions, chemiosmosis Glycolysis, The Calvin Cycle). The enzyme (Please select right answer one --> ( Glucase, Rubisco, Catalase, ATP synthase) can waste energy by (Please select right answer one --> (Making oxygen instead of glucose, Fixing oxygen instead of carbon dioxide, Fixing carbon dia\oxide during the day instead of a night, Reducing NADPH instead of oxidizing it)

Answer 1

Photorespiratio can happen during:

The Calvin Cycle.

Explanation:

In normal Calvin cycle CO_{​​​​​2} is added to Ribulose-1,5- Bisphosphate by the enzyme Ribulose -1,5-Bisphosphate Carboxylase (oxygenase) to give two molecules of 3- Phosphoglycerate. These 3 -phosphoglycerate molecules are consumed in the synthesis of sugars.

Where as during photorespiration oxygen is added to the Ribulose - 1,5 - Bisphosphate by the same enzyme Ribulose -1,5 - Bisphosphate Carboxylase (oxygenase) to give one molecule of 3 - phosphoglycerate and one molecule of phosphoglycerate. Thus carbon dioxide is not fixed during photorespiration.

The enzyme involved is Rubisco.

Here the enzyme acts as Oxygenase but not as Carboxylase as explained above.

Photorespiration wastes energy by Fixing oxygen instead of Carbon dioxide.