Mitosis

Mitosis is a type of cell division whose major purpose is growth and to replace worn out cells. It produces two new cells that are identical to each other, and to the parent cell.

We demonstrated the 5 phases of mitosis with the help of frosting on donuts:

20161123_120831_resized

1. Interphase

-The DNA in the cell is copied in preparation for cell division, this results in two identical full sets of chromosomes

-Outside of the nucleus are two centrosomes, each containing a pair of centrioles, these structures are critical for the process of cell division

-During interphase, microtubules extend from these centrosomes

2. Prophase:

-The chromosomes condense into X-shaped structures

-Each chromosome is composed of two sister chromatids, containing identical genetic information

-At the end of prophase the membrane around the nucleus in the cell dissolves away releasing the chromosomes

-The mitotic spindle, consisting of the microtubules and other proteins, extends across the cell between the centrioles as they move to opposite poles of the cell

3. Metaphase:

-The chromosomes line up neatly end-to-end along the centre (equator) of the cell

-The centrioles are now at opposite poles of the cell with the mitotic spindle fibres extending from them

-The mitotic spindle fibres attach to each of the sister chromatids

4. Anaphase:

-The sister chromatids are then pulled apart by the mitotic spindle which pulls one chromatid to one pole and the other chromatid to the opposite pole

5. Telophase:

-At each pole of the cell a full set of chromosomes gather together

-A membrane forms around each set of chromosomes to create two new nuclei

-The single cell then pinches in the middle to form two separate daughter cells each containing a full set of chromosomes within a nucleus. This process is known as cytokinesis

 

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s