- Cell happen to be fundamental unit of life.
- New cells will arise from existing cells.
- A cell will divide to give rise to two cells and these two cells can form four cells and so on. This is termed as “Cell reproduction” or “Cell division“.
- Cell division usually occur by Mitosis or Meiosis .
Following are the few differences between Mitosis and Meiosis:
|Mitosis is type of cell division occurring in somatic cells to form to identical daughter cells.
|Meiosis is type of cell division occurring in germ cells cells to form to four haploid cells with varied genetic information compared to parental cells.
|Forms all kinds of cells required for growth and repair. Do not form gametes or sex cells
|Formation of gametes – Sperm and egg
|Place of occurrence
|Germ or reproductive cells
|No. of stages
|Completes in two stages
|Simple and short
|Longer with many sub stages
|Present to form gametes with different genetic identity
|Pairing of homologous chromosomes
|Yes. Pairing observed from zygotene of prophase I till metaphase I.
|Mother cell or parental cell
|Can be haploid or diploid
|centromere towards equatorial plate and ends of chromosomes point to poles
|At metaphase I, Centromere in towards poles and Chromosome ends towards equatorial or metaphase plate.
|Homologous chromosome are not separated.
|Homologous chromosome gets separated at anaphase I.
|Centromere division takes place at anaphase I.
Sister chromatids gets separated.
|Centromere division and sister chromatid separation takes place only at anaphase II
|Completely disappear at telophase I
|Doesn’t disappear completely by telophase I
|Two copies of each chromosome (homologous chromosomes) end up at poles.
|Single copy (but replicated ) of each chromosome (haploid) end up at pole at the end of telophase I
|Remains same as parental cell
|Reduced to half ( 2n to n)
|Type of reproduction
|The genetic make up of daughter cells are identical to parental cell. (diploid)
|The genetic constitution of daughter cells usually differs from parental cell due to crossing over – each chromosome will a mix of both paternal and maternal genes. Independent assortment of homologous chromosomes at metaphase I also adds to genetic constitution variation observed in embryo, formed after fertilization.
Daughter cells formed are haploid.
Image Credit: Biology openstax