The Cell Cycle Mitosis and Interphase

Interphase The time between cell division Cell is doing its job DNA duplicates- chromosomes make exact copies of themselves Genetic material is all strung out as chromatin Nuclear membrane clearly in place

Mitosis Cell divides to form two new identical cells Can look at four different stages –Prophase –Metaphase –Anaphase –Telophase

Prophase DNA condenses to form distinct chromosomes Nuclear membrane disappears

What is a chromosome? the nucleus is the control center which has the genetic material which is DNA (deoxyribonucleic acid) * lots of DNA when it is bunched up is called a chromosome

Chromosome CHROMOSOMES = LOTS OF DNA Chromosomes are only visible during cell division

Metaphase Chromosomes line up in the middle (equator) of the cell Spindle fibers attach

Anaphase Chromosomes separate and move toward the opposite ends of the cell (poles)

Telophase Chromosomes reach the poles New nuclear membrane forms Chromosomes unwind to become thread-like chromatin again

Cytokinesis The cytoplasm is evenly divided New cell membrane forms in animal cells New cell wall is built across for plant cells

What is the end result of mitosis?

OK, fine…but who really cares about MITOSIS and diving cells???

Nerve cells… …remain in INTERPHASE for long periods of time. They go through mitosis about once every 75 years. So?…

Damage to these cells… …is often very serious.

Some damage is not permanent Gloria Estefan was involved in a tragic tour bus accident. Surgeons were able to repair her nearly severed spinal chord. She recently donated $1,000,000 for spinal chord injury research---->

Cancer cells… …behave much differently than nerve cells. …spend very little time in interphase and go through mitosis uncontrollably. Approx. 1/10,000 of your cells are cancerous-the good news-your defense cells usually kill them fast-->