Question

The durations of mitotic stages in two situations,(A and B) are tabulated below.

Phase	Duration of Mitotic stages (in Minutes)
	A	B
Interphase	1356(22.6 h)	870(14.5h)
Prophase	126	54
Metaphase	24	14
Anaphase	5	3
Telophase	22	11
Total	1533(25.6 h)	952(15.9 h)

Following are some interpretations:
I. 'A' and 'B' indicate the same plant tissue grown at higher and lower temperatures respectively.
II. 'A' indicates a slow growing plant species and 'B' indicates a fast growing plant species.
III. Both 'A' and 'B' indicate dormant plant tissues with excessively long interphase.
The correct interpretations is/are

• A. I and III
• B. II and III
• C. III only
• D. II only

Answer 1

Answer: (D)

The cell cycle is the series of events that takes place in a cell leading to its division and duplication. A cell cycle is divided into two periods interphase and mitotic phase. Interphase is further of three stages, $G_{1}, S$ and $G_{2}$. During interphase cell grows, accumulating nutrients needed for cell division. The most significant event of interphase is the replication of genetic material $(DNA)$ in $S$ phase. Interphase lasts for at least $90\%$ of the total time of the cell cycle. Mitotic phase consists of nuclear division. It is a relatively short period of the cell cycle, accounts approximately $10\%$ of the cell cycle. The duration of cell cycle varies among organisms and among cells of different tissues such as mature cells take longer time for cell cycle whereas cells at embryonic stage take short time. Considering the given data then duration of each event of cell cycle in plant $A$ is comparatively more than plant $B$, it can be interpreted that plant $A$ is slow growing species and plant $B$ is faster relatively.