CELL DIVISION: Mitosis & Meiosis
Can be divided into 2 stages:
- G1 Growth phase 1.
- S Synthetic phase.
- G2 Growth phase 2.
- During Synthetic phase, DNA duplicates. The genetic material doubles mean from 2N it becomes 4N.
- M Mitosis/Meiosis.
- C Cytokinesis.
Mnemonic:“Go Sally Go! Make Children!”
It is an equational division. Occurs in somatic cells.
Prophase, Metaphase, Anaphase, Telophase
Mnemonic: “People Meet And Talk”
- Coiling of chromatin occurs, forming thin long threads.
- By the end, chromosomes start forming,
- Nucleolus & nuclear membrane starts disappearing by the end.
- Spindle fiber formation starts.
- Centriole in animal cells starts moving towards the poles.
- Nuclear membrane and nucleolus has disappeared,
- Spindle fibers have formed,
- 2 types of spindle fibers occur chromosomal fibers that are attached to chromosomes at the centromere & continuous fibers that join the 2 poles.
- Chromosomes having two chromatids are seen,
- Chromosomes align themselves on the equatorial plate due to contraction of spindle fibers.
- Amphiastral mitosis occurs in animal cells & anastral mitosis occurs in plant cells.