Today’s learning outcome: 1) To learn the different phases of mitosis 2) To be able to identify the stages from images.

Today’s learning outcome:1) To learn the different phases of mitosis2) To be able to identify the stages from

images

Mitosis

Mitosis:1)Is the division of a nucleus following chromosome replication

2)The two resultant daughter nuclei have the same number of chromosomes as the parent nuclei making them genetically identical

3) Mitosis is involved in asexual reproduction as well as growth and repair of body tissues

Mitosis

Before mitosis occurs...Before the cell starts to divide, every DNA molecule must replicate

The two new molecules remain attached to each other in a small region called the centromere

Each DNA molecule becomes super coiled and compact.

Each chromosome can now be seen with a light micro scope and appears as two chromatids lying side by side, joined by the centromere

The Mitosis Cycle

Interphase This is the stage of mitosis when nothing is visible yet it is the most importantBecause this is when DNA replication occurs

Prophase Chromosomes slowly condense and become visible

The microtubules break down making the cell spherical in shape

PROMETAPHASEChromosomes have already replicated and are visible as daughter chromatids joined at a centromere.

Microtubules called spindle fibres develop from the centrioles (this is only present in animal cells)

MetaphaseThe nuclear envelope breaks down and The chromosomes become attached to spindle fibres, At regions called kinetochores, lining up along equator of the cell.

By the end of metaphase, all the chromosomes have lined up along the metaphase plate, with the spindle fibres pulling towards the pole

AnaphaseAnaphase, begins when the kinetochores split and the daughter chromatids are pulled to opposite poles of the cell by spindle fibres

TelophaseTelophase can be considered as the reverse of prophase

The chromosomes begin to recon denseAnd new nuclear membranes reform around the two sets of chromosomes

A quick visual aid for exams!!It easy!!!!!

NOW IDENTIFING IMAGES....