Within a cell cycle, there are 3 main stages, including interphase (G1, S, G2 aka largest phase), which then leads to mitosis and cytokinesis.
Interphase: An active period during which the cell carries out many biochemical reactions and grows larger.
: A period of growth, DNA transcription and protein synthesis
The period during which all DNA in the nucleus is replicated.
Cell prepares for division. There are more organelles and DNA condenses into visible chromosomes.
- Spindle microtubules grows
- Chromosomes are becoming smaller by
- Each chromosome consists of
two identical chromatids formed by DNA replication held by centromere
- The nuclear membrane has broken down and chromosomes have moved to the equator
- Spindle microtubules from both poles are attached to each centromere, on opposite sides.
centromeres have divided and the chromatids have become chromosomes
- Spindle microtubules pull the genetically identical chromosomes to
- All chromosomes have reached the poles and
nuclear membranes form around them
- Spindle microtubules break down
- Chromosomes uncoil
and are no long individually visible
Mitosis is used in eukaryote whenever genetically identical cells are needed eg. embryonic development, when the large cell produced by fertilization (zygote) divides repeatedly to produce many smaller cells; growth; to reproduce asexually
(cancers) are the result of uncontrolled mitosis. The normal control of mitosis in a cell fails, due to a change in the genes of the cells. This can happen in any tissue or organ and can spread to any part of the body.
- A contractile ring composed of
- actin filaments
forms just inside the plasma membrane at the former metaphase plate. The actin filaments pull the equator of the cell inward, forming a cleavage furrow. It then separates the membrane into two
- A cell plate forms along the equator of the parent cell during telophase from enzymes. Then, a new cell membrane and cell wall form along each side of the cell plate and waste is carried out through vesicles
That is the end of the cell cycle/ Mitosis!
Written by Venetia (Biology)