Question

Read the following statements about cell division and select the correct ones.
(i) M phase represents the phase when actual cell division occurs and I phase represents the phase between the two successive M phases.
(ii) In the twenty four hours average duration of the cell cycle of a human cell, cell division proper lasts for only about an hour.
(iii) M phase constitutes more than $95\%$ of the duration of the cell cycle.
A. (i) and (ii)
B. (ii) and (iii)
C. (i) and (ii)
D. (i), (ii), (iii)

Answer 1

Hint: The cell division is an important process occurring in the living cells and as a result of the cell division a cell divides into two daughter cells. During the cell division, duplication of the genetic material also takes place and finally different organelles and cytoplasm is distributed to the daughter cells.

Complete answer:
The process of formation of two daughter cells through the division of the parent cell is known as cell division. The cell division is important in living cells as they are responsible for various biological processes.

The process of cell division is also known as cell cycle. The cell cycle is divided into two main stages which are the interphase and the mitotic phase. The mitotic phase causes the separation of daughter chromosomes. The replicated chromosomes, organelles and cytoplasm move into two parts to form two different daughter chromosomes. The interphase is the phase where the growth of the cell takes place and it starts to accumulate nutrients that are needed for mitosis.

The cell cycle can be divided into four distinct parts which are the $G_1$, $S$, $G_2$ and M phase. The $G_1$, $S$, $G_2$ phases are collectively known as Interphase. The interphase is the changes that occur in a new formed cell. It occurs before the cell becomes able to divide itself. It is also known as the preparatory phase. The interphase occurs in between two successive mitosis divisions and so it is also called as intermitosis. The interphase is the longest phase in the cell division and can extend up to about ninety five percent of the total time required for the cell cycle. The interphase is divided into three phases which are known as the $G_1$, $S$, $G_2$ phases. After completion of this phase, the cell enters the mitotic phase.

The mitotic phase is the phase in which separation of chromosome takes place into two daughter cells. The M phase or the mitotic phase is a complex phase and is relatively shorter than the interphase. In the mitotic phase, the pairs of chromosomes condense and are separated to opposite sides of the cell. When the separation of chromosomes along with the separation of cell organelles are completed and moved into separate sides, the process of cytokinesis takes place. After this process, the dividing cell is divided into two separate daughter cells.

Hence, The correct answer is option (A).

Note: The complete process of cell division can be divided into two important parts which is the interphase and the mitosis phase. The interphase is the longest phase and is the time where the cell grows and prepares itself to divide. The interphase is divided into three phases such as $G_1$, $S$, $G_2$ and completion of these phases leads to the mitosis or the actual cell division phase.