Question

The chromosome number of the foot of fern embryo is 6, the chromosome number of its leaf will be
A. 6
B. 12
C. 18
D. 3

Answer 1

Hint: Each chromosome is composed of a single molecule of DNA and protein. DNA is considered as the genetic material of an organism as it carries information regarding the growth and development of an organism. Since the embryo and the leaves have the same ploidy, the chromosome number would also be the same.

Complete answer: Cell cycle is also called cell division. The cell has to undergo a series of events in order to divide and cell and produce two identical daughter cells. Mitosis is a type of cell division which involves replication and separation of the nuclei to produce two identical daughter cells. The series of events that are involved in the process of mitosis are prophase, prometaphase, metaphase, anaphase, and telophase. The preparatory phases of cell cycle involve thickening of the chromosomes. During metaphase, the chromosomes are lined in the centre of the cell that is to be divided. Chromosomes are divided from the centromere in the anaphase. This gives rise to an equal number of chromosomes which tends to move to the ends of the cell. By the time of telophase, the chromosomes are reached to the ends or poles of the cell and are ready for nucleoplasm division. The vascular parts of plants develop from the embryo of the plant. The embryo of fern is a diploid structure. The chromosome number of leaves will be the same as that of the chromosome number of the foot of fern. This is due to the mitosis of the embryo cells which will have the same number of chromosomes.
Hence, option A is the correct answer.

Note: Chromosomal recombination during the process of meiosis plays a significant role in genetic diversity. In human cells, chromosomes are of two types. They are 22 pairs of autosomes and one pair of sex chromosome. The sex chromosome is linked with the determination of the sex of an individual.