Question

The sequence of cell cycle is
A.S, M, $G_1$ and $G_2$
B.$G_2$, $G_1$, S and M
C.M, $G_2$, $G_1$ AND S
D.$G_1$, S, $G_2$ AND M

Answer 1

Cell cycle is the ordered sequence of events that takes place prior to cell division. It helps the cell to prepare for the cell division leading to the formation of two daughter cells.

Complete answer:
The cell cycle is broadly classified into the interphase and the Mitotic or M phase. The interphase comprises about 90% of the total time of the cell cycle and is made of three phases- $G_1$,S and $G_2$. The $G_1$ phase is the phase where the cell increases synthesis of its proteins, increases its organelles and also grows in size. The $G_1$ phase also comprises a checkpoint which ensures that only those cells that are prepared to divide leaves the $G_1$ phase and enters the S phase. The S phase or Synthesis phase is where DNA replication takes place. The rate of transcription and translation are quite low during this phase. The $G_2$ phase follows the S phase, where the protein synthesis increases and the cell prepares itself for mitosis. The $G_2$ phase also consists of a checkpoint which ensures only those cells that are prepared for division enter into the M phase. The M phase is where cell division takes place leading to the formation of two daughter cells that receive equal amounts of genetic material from the parent cell.

Hence, the correct answer is option (D)

Note: The cell cycle is a very important process that helps cells to grow and increase in number. Regulation of the cell cycle is also of importance which are mediated by the cell cycle checkpoints as well as other factors because unregulated cell cycle can lead to cancer.