3.24 c

Recap: nucleus contains chromosomes, during interphase cells are involved in DNA replication.

Signs:

1.       Break down of nuclear membrane (nucleus breaks down) known as PROPHASE, chromosomes become visible as a pair of chromatids.

2.       With the nucleus gone, a network of protein molecules “spindle/fibres” extended from one side of the cell to the other. What occurs in late prophase the chromatids will move towards the spindle.

3.       METAPHASE:  chromatids are attached to the spindle fibre in the “middle”

4.       ANAPHASE: the spindle fibre shortens pulling one chromatid one way and the other chromatid another way, they are moving apart, they move to the poles of the cell, separate pair of chromatids.

5.       TELOPHASE: the nucleus begins to reform around the chromosomes at both ends of the cell, so we see the formation of 2 nuclei at opposite sides of the cell

6.       CYTOKINESIS: the cell splits into 2 NOT PART OF MITOSIS, the cell moves inwards dividing the cytoplasm in half, resulting in 2 halfs, NB: the each have 1 chromosome (same as parental cell)

7.       In humans we don’t see 1 cell dividing but 23 pairs separating at 1 time.