Question

Cell would normally proceed to mitosis without interruption

• A. Once it has entered the S phase
• B. Once it has entered the $G_2$ phase
• C. At any time during cell division activity
• D. None of these

Answer 1

The correct option is A Once it has entered the S phase

The availability of mitogen and energy rich compounds decide whether $G_1$ phase will be arrested ($G_0$ phase) or undergo S- phase. This point is called check point or $G_1$ cyclin or $G_1$ point. Once the checkpoint of $G_1$- phase is crossed and cell has entered S - phase, cell cycle will go on further division till completion.

So, the correct answer is 'Once it has entered the S phase'.