Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Some cell signalling receptors are at the cell surface with transmembrane domains that help them embed in the plasma membrane. Reason (R): They are localized at the cell surface as their activating ligands cannot enter the cell interior. In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A) \
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A) \
• C. (A) is correct but (R) is not correct \
• D. (A) is not correct but (R) is correct

Hint:

If a ligand is hydrophilic, it cannot cross the lipid membrane. It needs a cell-surface receptor to catch the signal and pass it inside.

Answer 1

The Correct Option is A