FLORA WORLD

  Cell division part:2 Meiosis or meiotic division   Meiosis : Meiosis is also called Reductional Division or Meiotic Division. The term meiosis was given by Farmer and Moore in 1905. Meiosis occurs in special cells called Meiocytes . For example, germ cells of sex organ, Pollen mother cell etc. Meiosis is a special type of division in which number of chromosome becomes the half of the parental cell. From one diploid parental cell, four (4) haploid daughter cells are formed.   Meiosis involves two divisions- 1. Meiosis I or Reductional Division or Heterotypic Division 2. Meiosis II or   Homotypic Division   1.   Meiosis I or Reductional division or Heterotypic division - It is also called Reductional Division because it involves formation of two daughter cells each with half the number of chromosomes as compared to the parent cell. It is completed into two phases- A.    Karyokinesis I B.    Cytokines...

  CELL DIVISION OR CELL REPROUCTION   Part:1   Mitosis or equational cell division or mitotic cell division   Firstly cell division was studied by Prevost and Dumas, when they described cleavage in zygote of frog. Cell division is the process by which cell divides or reproduce to form new daughter cells. Cell division is the means of reproduction in unicellular organisms. In almost all organisms which reproduce sexually, the cell division is of two types- A. Mitosis B. Meiosis   A.   Mitosis or equational cell division or mitotic cell division It was first discovered by Strasburger in 1870 in plant cells and in animal cell it was first discovered by W. Fleming in 1879. The term mitosis was given by W. Fleming in 1882. It occurs in somatic cells example; Meristematic cells of root and stem tip, skin cells, bone marrow etc. Mitosis is a kind of division, in which two daughter cells formed have the same number of chromosomes a...

  CELL CYCLE   Definition of cell cycle: Every cell has a fixed life span. During this period it grows, performs its activity and finally undergoes division to form new cells. This entire life span of the cell is called ‘ Cell Cycle’ .   Another words, all those changes which occur during cell growth and cell division collectively called ‘ Cell Cycle’.   Duration of cell cycle: Duration of cell cycle can vary from organism to organism and also from cell type to cell type. Example:                Duration of cell cycle is 20 minutes for bacterial cell, 20 hours for onion root tip cells.   The cell cycle is divided into two phases:- A.    Interphase B.    M phase or Mitosis phase   A.   Interphase:                       ...