Question
Mon March 05, 2012 By: Krishna Ramesh

Please explain this statement Multicellular organisms have special lineages of cells in specialized organs which have only half the no. of chromosomes and half the amount of DNA as compared to the non-reproductive cells.

Expert Reply
Mon March 05, 2012

There are two basic types of cell in a muticellular organism:

  1. Somatic, or body cells
  2. Germ , or Reproductive cells.

The somatic cells are the primary components of most organisms, making up everything except some of the cells in reproductive organs. The somatic cells of humans have 23 pairs of chromosomes, or 46 chromosomes overall, and are thus known as diploid cells.

Germ cell, by contrast, undergoes a process of cell division known as meiosis, whereby it becomes a haploid cell—a cell with half the basic number of chromosomes, which for a human would be 23 unpaired chromosomes.

The sperm cells in a male and the egg cells in a female are both haploid germ cells: each contains only 23 chromosomes, and each is prepared to form a new diploid by fusion with another haploid. Sperm cells and egg cells are known as gametes, mature male or female germ cells that possess a haploid set of chromosomes and are prepared to form a new diploid by undergoing fusion with a haploid gamete of the opposite sex.

 
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