Question

Assertion :Some cells enter $G_{0}$ phase leading to inactivation of cell cycle.
Reason : $G_{0}$ phase occurs due to non-availability of mitogen and energy rich compounds.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

The phase in which cells fail to divide further (do not undergo $S$- phase after $G_{1}$ -phase) is known as $G_{0}$ phase or quiescent stage. It occurs due to non-availability of mitogen and energy rich compounds. The cells remain metabolically active, but no longer proliferate unless called on to do so depending on the requirement of the organisms.