2.2 Mitosis

2026-03-04 23:32

Status: #new

Once Mitosis starts, Chromatin condense into Sister chromatids linked together by a Centromere (by coiling together the DNA)
There is a pair of centrosomes (consisting of two centrioles each)
The centrosomes and the network of microtubles will form the mitotic spindle
A radial array of microtubles begins to form around each centrosome (Aster)
- As these microtubules grow, they pull the centrosomes apart.
The nucleus then undergoes lysis (breaks) and the microtubules cover the former nuclear's area.
- Certain microtubules from the centrosomes known as Kinetochore microtubules will attach to each chromosome at the centromere.
- Polar Microtubules push the centrosomes apart as they grow
- Astral Microtubles they anchor the spindle apparatus

This phase begins once the centrosomes are at the poles of the cell
Aster Microtubules attach to the cell membrane
All chromosomes are lined up at the metaphase plate.
M Checkpoint ensures that the sister chromatids are attached to the opposite ends of the mitotic spindle.
- This happens after all kinetochore's are attached to the spindle

The enzyme "seperase" cleaves the cohesins (Protein that holds together sister chromatids) that binds the chromatids together
The kinetochores pull the chromatids apart
- This ensures we get two separate sets of the genome (the entire instruction set for an organism)
The chromosomes are then pulled by motor proteins attached to the kinetochores to move them towards opposite ends of the cell.
Microtubules begin to disassemble as the chromosomes start moving
- Cells additionally elongate during this process

Mitosis is complete!

Cleavage furrow at metaphase plate forms
- Caused by actin microfilaments that pull the cell inwards
- Eventually pinches the cell in two

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