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1. Photosynthesis is more of a problem for a plant when their stomata are closed

ID: 65990 • Letter: 1

Question

1. Photosynthesis is more of a problem for a plant when their stomata are closed because?

A. Oxygen levels increase from photosynthesis and complete with carbon dioxide for rubisco's active site

B. Carbon dioxide levels increase from photosynthesis and complete with oxygen for rubisco's active site

C. Water is lost when the stomata are open and is not available to accept electrons from photosystem 1

D. Oxygen cannot enter the leaf, blocking normal respiration, so the plants switch to photorespiration

E. Glucose cannot leave through the stomata and levels increase inside of the plant cell, causing dehydration by osmosis

Can you briefly explain why?

Explanation / Answer

A. Oxygen levels increase from photosynthesis and complete with carbon dioxide for rubisco's active site.

When stomata is closed, CO2 cannot enter leaves, and the CO2 concentration in the plants decrease. The increased oxygen levels now compete with the CO2 for the catalytic enzyme rubisco. This switches photorespiration, which includes waste energy expenditure.