Reproduction of body (somatic) Cells The Cell Cycle Reproduction of body (somatic) Cells Asexual Reproduction NO EXCHANGE OF DNA

Cell Cycle and Mitosis Mitosis is the phase of the cell cycle in which cells are reproduced: Reproduction of cells is necessary for: Growth of the organism Repair of damaged cells This orderly process assures that all of our cells will be identical

Chromosomes Chromosomes are on our DNA They carry all of our genetic information We have 46 – 23 from each parent They are in the NUCLEUS of all eukaryotic cells They float freely in Prokaryotic cells

Sister Chromatids These are the chromosomes after they have duplicated They are exactly the same as each other

Interphase The longest phase of the cell cycle Cells in interphase are performing life functions for the organism

Prophase First phase of mitosis – DNA uncoils and becomes visible under a microscope

Metaphase Chromosomes line up in the center of the cell

Anaphase Chromosomes begin to divide – One of each pair of sister chromatids on each side Chromatids

Telophase/Cytokinesis The nucleus reforms Two cells begin to separate Cytokinesis – two duplicated cells have formed

S Phase “S” stands for synthesis – G1 and G2 are GAP phases DNA is duplicated G1 and G2 are GAP phases During G1 the cell grows to normal size During G2 organelles are formed in preparation for the beginning of mitosis

Control Movement from S phase, G1 and mitosis are controlled by enzymes Only if new cells are needed, and the cell is healthy will the enzymes activate the cycle to begin

CANCER! When the cycle gets out of control, cancer results…. The cycle continues without stopping and a tumor results. More and more cells become affected by the mutation that caused the cycle to become disturbed

P 53 One gene that patrols the cells is the P53 gene This gene destroys damaged cells so that they will NOT reproduce Genes are made of proteins Proteins travel from cell to cell – using Protein channels on the surface of the cell membrane to enter and exit