Question

There are 14 chromosomes in each cell and 2C DNA after M-phase in a plant. Find out the correct match in the following table.

	Stage	Chromosome No.	DNA Content
a.	$G_1$	14	2C
b.	S	28	4C
c.	$G_2$	14	4C
d.	M	28	4C

• A. a and b are correct
• B. a, b and d are correct
• C. a and c are correct
• D. b, c and d are correct

Answer 1

The correct option is C a and c are correct

A cell cycle is a series of events that takes place in a cell during its growth period. A cell spends most of its time in the phase called interphase. During this phase of cell division, cell grows, replicates its chromosomes, and prepare itself for cell division. After interphase, cell undergoes mitosis, and completes its division.

Interphase is composed of three phases namely G${}_1$ phase or gap 1 phase (cell growth phase), followed by S phase or synthesis phase (DNA synthesis phase), which is followed by G${}_2$ phase or gap 2 phase (cell growth phase).

During G${}_1$ phase the cell is metabolically active and continuously grows but does not replicate its DNA.
During the S phase, the amount of DNA gets doubled in each cell. The number of chromosomes remains the same. The S phase also functions as a checkpoint for the cell. So, after S phase the amount of DNA will be 4C but the number of chromosomes will remain same that is 14. During the G${}_2$
phase, proteins are synthesised in preparation for mitosis while cell growth continues but the chromsome number and DNA content is same as S phase. M Phase represents the phase when the actual cell division or mitosis occurs and the chromsome number and DNA content is same as that of the parent cell. Hence, the correct answer is option c.