Mitosis The Division of Somatic Cells Biology is

Mitosis The Division of Somatic Cells

Biology is the only subject in which multiplication is the same thing as division!

Where it all began: • You started as a cell smaller than the period at the end of this sentence. .

And now you are you!

Getting from there to here: I. Going from an egg to a baby, the original fertilized egg has to divide and divide

II. Why do cells divide? A. One-celled organisms: 1. For Reproduction (clones) • Example: Bacteria

B. Multi-celled organisms 2. For growth & development – From fertilized egg to adult – Example: Growing more muscle or fat 3. For repair & replacement – Replace cells that die from normal wear and tear or from injury – Example: Repairing a cut

Summary Slide

III. How cells divide? Stages of Mitosis

A. Interphase • Cell spends most of its time here growing and doing normal jobs • Cell copies DNA during interphase (replication)

B. Prophase • DNA winds into chromosomes – This keeps DNA organized as the nucleus disappears.

Prophase

C. Metaphase • Chromosome line up in the middle – Attached to protein “cables” that will help them move (spindles)

Metaphase

D. Anaphase • Chromosomes separate and start to move to opposite ends

Anaphase

E. Telophase • Cell starts to divide – 2 nucleus form!

Telophase

F. Cytokinesis • DNA unwinds again – Cytoplasm divides – 2 new cells can now do their everyday jobs

IV. The results of MITOSIS • 2 new daughter cells – Get 2 exact copies of the original cells • Same DNA • “Clones”

Video of Mitosis

Summary Slide

A. Cancer • A mistake in the cell cycle that is the result of uncontrolled cell division

• Cancerous cells for masses of tissues called tumors. These take nutrients away from normal cells.

Benign Tumors • Benign tumors are nondangerous/noncancer ous tumors • Cells of the tumor are normal and there is no danger of them invading other tissues… yet!!!

Malignant Tumors • Malignant tumors are cancerous cells that have different shapes and will invade or destroy other tissues

If malignant cells go undetected… • Then the cancer has the ability to enter the circulatory system (the blood stream) and spread through the body. This is called metastasis

Cancer Prevention • Live a healthy lifestyle • Eat lots of fruits, veggies, and grains • Exercise • Visit the doctors for checkups, especially if a type of cancer runs in your family