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).

CYTOKINESIS

• animal cell…cell membrane grows into the center of the cell at the center of the parent cell and divides it into 2 daughter cells of equal size; called a cleavage furrow

• plant cells…form a cell plate (from the parent cell wall).