Cell Cycle and Chromosomes

Chromosomes are best seen during cell division when they are most condensed, especially during metaphase. They are seen by light microscope or by special stains.

A chromosome with the centromere so placed that it divides the chromosome into two arms of strikingly unequal length is sub-metacentric. Such chromosomes are L-shaped.

A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act on instructions to make molecules called proteins. These are found on chromosomes.

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The correct option is (2).

It is the second growth period of the cell cycle, following DNA replication and preceding prophase, during which the cell forms the materials that make up the spindle. RNA and non-histone proteins are synthesised in this phase.

Phragmoplast is the cytoplasmic structure that forms at the equator of the spindle, after the chromosomes have divided during the anaphase of plant.

Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information. Thus, meiosis involves two nuclear divisions and one chromosomal division.

This is the correct sequence of the stages of prophase 1.

This is the correct sequence of the cell cycle. The G1 stage stands for GAP 1. The S stage stands for synthesis. This is the stage when DNA replication occurs. The G2 stage stands for GAP 2. The M stage stands for mitosis.

Cell division by simple cleavage of the nucleus and division of the cytoplasm without spindle formation is called amitosis.

Correct sequence: Juvenile phase-Reproductive phase-senescent phase

Polyploidy is the heritable condition of possessing more than two complete sets of chromosomes. Polyploids are common among plants.

G1, S and G2 are the stages of interphase.

Mitosis is an equational division. The number of chromosomes remains the same in the two daughter cells as it was in the mother cell.