Question

What does 2n mean?

Answer 1

Hint: Chromosomes are thread shaped structures present within the nucleus of a eukaryotic cell. It is the basic unit of genetic traits passed on from parents to offsprings. The letter ‘n’ represents the number of chromosomes present in a somatic cell.

Complete answer:
The ‘2n’ stage represents the diploid stage. During this condition, two sets of chromosomes are present within one cell. In almost all human cells, that is somatic cells the diploidy results in 46 chromosomes in 23 pairs. Diploid cells possess two copies of genes as a result of two sets of chromosomes. During the cell cycle, diploid cells are produced from parent diploid cells by means of mitosis of equational division.

Additional Information: Two haploid cells (n) , that is, gametes produce a diploid cell by the process of fertilization. The process by which a diploid (2n) parent cell give rise to two haploid (n) daughter cells are known as meiosis or reduction division.

Ploidy can be defined as the number of sets of chromosomes a cell can possess. It can be a monoploid having 1 set of chromosomes or have ploidy upto heptaploid having 7 sets. Polyploid refers to any cells that are triploid or more.

Note: Another state of ploidy is n+n which represents a dikaryon phase characterized by the presence of two nuclei within the same cell. It is present predominantly in fungal classes like Ascomycetes and Basidiomycetes. The two nuclei can later fuse together to form a single nucleus. The dikaryon phase is a part of the reproductive cycle in fungi.