As the name suggests, the main difference between multicellular and unicellular organisms is the number of cells that are present in them. This leads to the development of all other…
Diploid and Haploid Cells
Diploid and haploid cells are involved in sexual reproduction of higher eukaryotic organisms. The following BiologyWise article will cover some information related to the diploid and haploid cells.
In a biological cell, the number of complete chromosomal sets is called ploidy. The somatic cells of the human body are diploid in humans. However, the sex cells, that is, sperms and egg are haploid. In certain plants, amphibians, reptiles, and insect species, one may see tertaploidy (four set of chromosomes). So what are these diploid and haploid cells? If you are searching for answers to these questions, then the following paragraphs will help answer your queries.
The sex cells or gametes contain haploid cells which means that these cells have one set of chromosomes, that is, 23 chromosomes. There are only 23 chromosomes in the human egg and 23 chromosomes in the human sperm. These cells are formed after they go through a special cell division called meiosis. Therefore, the progeny inherits one set of chromosome from the mother and one set from the father. After fertilization, they form a diploid zygote. This diploid zygote develops into a diploid species.
Diploid cells have two homologous copies of each chromosome inherited from the mother and father. All mammals are organisms of this type, with the exception of a few species. There are 46 chromosomes in human diploid cells and the human haploid cells have 23 chromosomes. The diploid cells are indicated by 2n = 2x and haploid cells are indicated by n, where n = number of chromosomes and x = monoploid number.
The gametes from diploid parents undergo meiosis, and fertilization of haploid egg and sperm occurs. This forms a diploid zygote that contains maternal chromosome and paternal chromosome. This diploid zygote undergoes mitosis that leads to the formation of a diploid organism.
Definition: These cells contain a complete set (or 2n) of chromosomes.
Cell Division and Growth: Haploid cells from the mother and father, during the process of reproduction fertilize to form a diploid zygote. This zygote undergoes mitosis to produce more diploid cells.
Examples of Organisms: Humans and almost all mammals are diploid organisms.
Definition: Haploid cells contain half the number of chromosomes (or n) in the nucleus. That is they consist of one set of chromosomes unlike the diploid, which contain two sets.
Cell Division and Growth: Haploid cells are formed after the process of meiosis, a type of cell division where the diploid cells divide to form haploid germ cells.
Examples of Organisms: Yeast and fungi are permanently haploid. Other organisms like male bees, wasps, and ants are haploid organisms.
It is important to note that most of the meiotic organisms spend some portion of their life as a haploid cell and then as a diploid.