Question

Assertion :High pH in guard cells activate phosphorylase to convert starch into glucose $1-P{O}_4$. Reason: Stomach open when pH is low.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

There is a starch to sugar conversion theory for the opening and closing of stomata. The stomata open in neutral or alkaline pH which prevails during daytime due to constant removal of carbon dioxide by photosynthesis.

They remain closed during the night where there is no photosynthesis and due to the accumulation of carbon dioxide carbonic acid is formed which causes the pH to be acidic. Sayres proposed that interconversion of starch and sugar is regulated by the pH.

This was supported by the detection of the enzyme phosphorylase this enzyme is responsible for starch glucose interconversion.

So, the correct option is 'Both Assertion and Reason are correct and Reason is the correct explanation for Assertion'