The Story of Mitosis

A sample presentation offered by Ms. Mason-Howerton

Why Care about Mitosis?

Mitosis is how cells divide.

Imagine what would happen if our cells did not divide.

We could not grow or heal our bodies if we got hurt.

That would be bad for Skateboard Mike.

Good thing for Skateboard Mike his

cells can heal!

So how does mitosis work?

First, a cell enters Interphase• During the first part

of interphase, the cell grows larger. This is called the G1 stage.

• After growing to the point where the surface area to volume ratio is too large, the nucleus will signal for its DNA to replicate.

Interphase Part Two

• Within the nucleus, the DNA replicates providing the cell with two complete copies of its genetic material.

• This is called the S stage of interphase.

Interphase Part Three

• During the next stage of interphase, the centrioles replicate and the cell prepares for division.

• This is called the G2 stage.

Cells Spend Most of Their Lifespan in

Interphase.

After Interphase, a Cell Will Begin Prophase

• During prophase, the nuclear envelope disintegrates after DNA supercoils into a chromosome configuration.

• Centrioles move to opposite poles of the cell.

Next, the Cell Enters Metaphase

• During metaphase, the chromosomes move to the equator of the cell.

• The spindle fibers, which associate with the centrioles, attach to the sister chromatid pairs.

Anaphase & Telophase

• During Anaphase, the sister chromatids are pulled away from each other, and are moved towards the opposite poles.

• During Telophase, the chromatids have separated into two distinct nuclei.

Cytokinesis• During Cytokinesis, the

cell’s cytoplasm divides after the nuclear envelopes finish reforming around the chromosomes.

• In animals, a cleavage furrow is the site where this occurs; which is positioned at the equator.

• In plants, a cell plate is laid down across the equator of the cell.

So that is how you get new cells!

Acknowledgements:

• Images courtesy of http://www.tech4learning.com, http://www.imp.ac.at/events/images/mitocheck/Mitosis.jpg

• Content found in Glencoe Science BIOLOGY: The Dynamics of Life, http://www.biology.arizona.edu/

Don’t even THINK about using Skateboard Mike for

profit. He is so cool, he has been copyrighted.