What is happening in this picture?

Cell Division Why do it? VIDEO

Cells must divide for… Growth of the organism (Mitosis) Repair of damaged cells (Mitosis) Replacement of dying cells (Mitosis) Reproduction of the organism (Mitosis or Meiosis)

REPLICATION / DUPLICATION The most important part of cell division is the __________________________________________of chromosomes and the separating of DNA into daughter cells!! REPLICATION / DUPLICATION How is DNA organized inside the nucleus? VIDEO Mitosis - YouTube

Karyotype – an analysis of chromosomes for identification of genetic abnormalities, cell sample can be gathered through amniocentesis

The Cell Cycle How long does cell division take? G1 (9-11 hours) S Phase (5-6 hrs) G2 (3-4 hrs) Mitosis (~2 hrs) Prophase Metaphase Anaphase Telophase

Budding yeasts, can progress through all four stages of the cell cycle in only about 90 minutes! Early embryos have cell cycles that last only 30 Minutes!!! These early embryonic cell cycles rapidly divide the egg cytoplasm into smaller cells. There is no G1 or G2 phase, and DNA replication occurs very rapidly.

CELL DIVISION Both Mitosis AND Meiosis involve 6 distinct stages involving specific changes inside the cell Interphase Involves the duplicating of chromosomes and organelles and cell growth (G1, S, G2) Chromatin is spread out in the nucleus

Prophase Chromatin coils up to form chromosomes Centromeres form to connect sister chromatids The nuclear envelopes starts to break down

Metaphase Centrioles move to opposite poles spindle fibers form and attach to the centromeres chromosomes line up along the equatorial plane (middle)

Anaphase Chromosomes are pulled to opposite poles of the cell

Telophase The cell membrane pinches inward to form two new cells Nuclear membranes reform around the chromosomes

Cytokinesis 2 New daughter cells seaparate from eachother! What is cancer? Cancer Cancer genes we all have Uncontrolled, abnormal cell growth Could be brought on by environment carcinogens like UV rays, cigarette smoke, asbestos exposure etc.

Skin Cancer in Teens Children's Melanoma

Tanning Facts 5 9 3 4 7 8 6 1 2 Up to 80% of sun’s UV rays can penetrate through clouds & fog Glass blocks most UVB rays, but NOT UVA Current research shows that when used as directed, sunscreens are safe and effective Only some vit.D can be produced using UVB, other sources are in food (fish, milk, cereals) Use “braod spectrum” sunscreen (UVA & UVB) Less likely to get skin cancer, but higher chance of dying from it Any tan is a sign of skin’s attempt to repair sun damage and prevent injury that can cause gene defects Actually, only 23% of lifetime exposure is before age 18, sun protection is important at all ages! Indoor tanners have pose a higher risk of ALL forms of skin cancers

Cells can divide in two different ways… MITOSIS MEIOSIS

MEIOSIS VIDEO Difference between mitosis ans meiosis – YouTube Biology : Meiosis - cell division - YouTube

MITOSIS MEIOSIS Involved With ASEXUAL (not sexual) reproduction: growth, repair and replacement Involved With SEXUAL reproduction: making eggs and sperm (gametes) – called “gametogenesis) 2 Cell divisions occur and 4 daughter cells are produced Only 1 cell division occurs and 2 daughter cells are produced Daughter Cells are genetically different from the parent cell and each other! (1/2 the chromosome #) Daughter Cells are genetically identical to the parent cell (same chromosome #) Parent Cell and Daughter Cells have the “DIPLOID” # of chromosomes (2N or 46) Parent Cell is “DIPLOID” (2N) but daughter cells are “HAPLOID” (half) or N or 23

Prophase | Genetics | Biology - YouTube

Spermatogenesis: The creation of 4 haploid sperm cells from one parent cell Oogenesis: The creation of 1 haploid egg cell from one parent cell (the other 3 become non-functional polar bodies)

On back of Quest… Describe one type of cancer. Inlcude: Name of Cancer Organ(s) affected 1 possible Risk Factor/Cause 1 possible treatment