1. Cell Cycle and Mitosis SBI3U @ RHSA

2. Cell Cycle The life cycle of all cells has two main parts: 1. Interphase 2. Mitosis and cytokinesis

3. Interphase A cell spends most of its lifetime in interphase growing and replicating chromosomes. Interphase is divided into: 1. G1 phase 2. S phase 3. G2 phase

4. Interphase: G1 phase During the G1, or growth 1 phase of interphase, the cell makes new molecules and grows larger. This phase can be long or short depending on the type of cell and the health of an organism.

5. Interphase: S phase S is for synthesis of more DNA. During the S phase the uncoiled chromosomes, called chromatin, are replicated or duplicated. The nucleus of cells in interphase is a dark blob of chromatin.

6. Find onion cells in interphase!

7. Sister Chromatids Both copies of the chromosome are joined at the centromere. The identical copies are called sister chromatids.

8. Interphase: G2 phase During the G2 or growth 2 phase the cell again synthesizes more molecules and grows larger. Now the cell is big enough to divide into two new cells by mitosis.

9. Find cells undergoing Mitosis and Cytokinesis

10. Mitosis Only a very short part of a cell’s life is spent in mitosis. Mitosis is the elaborate process a cell has to ensure the precise division of all chromosomes. After mitosis, the cell divides all the cytoplasm and organelles in the process of cytokinesis.

11. Online resources Mitosis animation http://www.cellsalive.com/mitosis.htm Mitosis videos http://www.sumanasinc.com/webcontent/animations/content/ mitosis.html http://www.sumanasinc.com/webcontent/animations/content/ mitosis.html http://www.biostudio.com/d_%20Mitosis.htm Mitosis quizzes http://school.discoveryeducation.com/quizzes6/muskopf/mito sis1.html http://school.discoveryeducation.com/quizzes6/muskopf/mito sis1.html http://www.phschool.com/science/biology_place/biocoach/mi tosisisg/quiz.htmlhttp://www.phschool.com/science/biology_place/biocoach/mi tosisisg/quiz.html http://local.brookings.k12.sd.us/biology/ch10celldivision/mito sis_review.htmhttp://local.brookings.k12.sd.us/biology/ch10celldivision/mito sis_review.htm