Mitosis

Mitosis

Production of 2 genetically identical cells w/ same no. of chromosomes as parent cell

Meiosis

Stages in the M Phase

PMAT, Cytokinesis

Prophase

1. DNA condenses via thickening and shortening, making 2 chromatids of the chromosome visible

2. Nucleolus disassembles

3. Centrosomes migrate to opposite poles of the cell, S.F formation initiates as microtubules are radiated

4. Kinetochores form on the chromosome, one on each side of the centromere

Centromere function

chromosome region to which the microtubuels of the S.F attach to, via the kinetochore.

In Prophase, why does the DNA condense

To prevent tangling of DNA during cell division

Prometaphase

• NE breaks down

• Spindle microtubules grow & shrink to find where nucleus was, then they attach kinetochores on chromosomes

Metaphase

Spindle microtubules lengthen and shorten to line up the chromosome along the metaphase plate.

Anaphase

1. Centromere Splits, the sister chromatids are separated as the S.F contractors and shortens.

2. This pulls the chromatids back towards the poles where centrosomes are.

3. Since sister chromatids are formed by Semi-conservative replication, an identical set of 46 chromosomes arrives at each spindle pole.

Telophase

• 46 chromatids arrive at each pole of the cell.

• NE begin to form around each set of chromosomes, forming 2 nuclei

• Microtubule S.F’s breaks down & Nucleolus reforms

• Chromosomes decondense, becoming less visible

Cytokinesis

After NE forms, the cytoplasm cleaves and 2 new genetically identical cells are formed