Diploid – Class 12 | Chapter – 1 | Short Notes Series PDF

Diploid: The term diploid refers to the cell containing two sets of homologous chromosomes wherein each chromosome in a set is obtained from each of the two-parent cells. Humans are diploid (2n), hence each human has two copies of chromosomes in the nucleus of their cells. This is to say that there are two copies of chromosome 1, two copies of chromosome 2, two copies of chromosome 3 and so on.

Other than the human sex cells, all cells are diploid, having 23 pairs of chromosomes. The sex cells in humans determine their sex/gender (sperms cells and eggs), which comprises a single set of chromosomes, referred to as haploid. This is the only instance wherein the homologous pair does not comprise two copies of the same chromosome. In other words, humans have 23 sets of homologous chromosomes, a total of 46 chromosomes, hence 2n = 46. In males, the paired sex chromosomes are X and Y homologs (XY), while in females it is the X and X homologs (XX).

Features of Diploid cells

  • Possess two sets of chromosomes while haploid cells have one set of chromosome.
  • They are represented as 2n and is different for different species.
  • This chromosome number is their number inside the nucleus of the cell.
  • The cells which are somatic in nature in the body are diploid.
  • Diploid cells reproduce through mitosis, and conserve their number of chromosomes by generating a copy of its chromosomes, and equally distributing their DNA amongst their daughter cells.

Chromosome number of different species:

Species Chromosome number
Garlic 16, 2n=16
Dogs 28, 2n=28
Elephant 56, 2n=56
Chicken 78, 2n=78
Humans 46, 2n=46

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By Team Learning Mantras