Post on 05-Jan-2016
Youtube links to watch
• http://www.youtube.com/watch?v=gwcwSZIfKlM
• http://www.youtube.com/watch?v=lpAa4TWjHQ4
10.2 Eukaryotic Cell Cycle
• Cell cycle--repeating phases of :– Growth (Interphase)– DNA replication (Interphase)– preparation for cell division (Interphase)– division of the nucleus and cytoplasm (cell
division—mitosis & cytokinesis)
Interphase
• G1: cell grows to mature size, makes more organelles
• S: chromosomes replicate
• G2: cell continues to grow and prepare to divide; cell forms specialized structures that help the cell divide (ex. microtubules)
2 Stages of Cell Division:
1. Mitosis: the process in which a cell’s nucleus divides into 2 identical daughter nuclei.
*Begins after interphase and ends before cytokinesis.
*PMAT (4 phases)
2. Cytokinesis: cytoplasm division (and organelles)
*Cell physically splits into 2
MITOSIS — 4 phases (PMAT): 1. PROPHASE
• chromosomes condense (coil up and become visible under a microscope).
• Centrosome helps to assemble spindle fibers.
• a pair of centrioles migrate to each pole of the cell (animal cells only).
• nuclear envelope and nucleolus break down (disappear).
2. METAPHASE
• spindle fibers arrange chromosomes in the middle of the cell along the equator of the cell. • spindle fibers link the chromatids of each
chromosome to opposite poles.
3. ANAPHASE
• centromeres divide• spindle fibers pull sister chromatids towards
opposite poles.• result =each pole has a full set of chromosomes.
4. TELOPHASE
• 2 daughter nuclei are formed• reverse of prophase: nuclear envelopes
form around each set of chromosomes; chromosomes uncoil to form a loose mass of chromatin; spindle fibers break down (disappear).