1. 2.5 Cell Division Oh Yeah! By Sam Terrell

2. 2.5.1 Outline the stages in the cell cycle, including interphase (G1,S,G2), mitosis and cytokinesis. (ch. 12 pg. 217) Interphase accounts for 90% of the cycle. Divided into subphases: G1 Phase (1st Gap), S Phase (Synthesis of DNA), and G2 Phase (2nd Gap). In the G1 phase, a cell grows until it reaches the S phase where chromosomes are duplicated, then it continues to grow in the G2 phase. The S phase is the only phase of the cell cycle when chromosomes are duplicated. After G2 Phase, the cell undergoes Mitosis (Prophase, Metaphase, Anaphase, Telophase); this is where the nucleus divides and distributes its chromosomes to the daughter nuclei. Then, in cytokinesis, the cytoplasm of the cell divides producing two daugher cells

3. An image of the cell cycle for visual learners… Isn’t it pretty? If you didn’t already know, the answer is yes.

4. 2.2.5 State that tumors (cancers) are the result of uncontrolled cell division and that these can occur in any organ or tissue. Obviously, all you need is that statement for the quizzes, but just think of this and you’ll never forget what a tumor is:

5. Another free-be: 2.5.3 State that interphase is an active period in the life of a cell when many metabolic reactions occur, including protein synthesis, DNA replication and an increase in the number of mitochondria and/or chloroplasts

6. 2.5.4 Describe the events that occur in the four phases of mitosis (prophase, metaphase, anaphase, and telophase). See ch.12 pg. 218 for an awesome diagram of mitosis. Prophase: the chromatin supercoils and condenses into chromosomes; the nucleoli disappears; each duplicated chromosome appears as a pair of sister chromatids joined together by a centromere; the centrosomes move to opposite poles of the cell, starting the formation of microtubules. Metaphase:The centrosomes are now on opposite poles of the cell; the chromosomes align on the equator; microtubules have attatched to the centromere of each sister chromosome. Con’t on next…

7. 2.5.4 (con’t) Anaphse: the paired centromeres of each chromosome separate, leaving sister chromatids; now all are separate chromosomes; chromosomes pulled to opposite sides of the cell. Telophase: the nuclear envelope begins to develop; chromatin begins to uncoil; the formation of a cleavage furrow begins.

8. 2.5.5 Explain how mitosis produces two genetically identical nuclei. DNA is coiled in the nuclear envelope forming chromosomes. The chromosomes are separated, moving to opposite poles of the cell. The cell divides into two sister cells forming 2 genetically identical nuclei. Note: this is the abridged version of what we just talked about.

9. 2.5.6 State that growth, embryonic development, tissue repair, and asexual reproduction involve mitosis. State that, and your done with 2.5 Cell division, not so bad right? Enjoy!

10. Vocab: Interpahse, G1, S Phase, G2, Mitosis, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis, Cytoplasm, Supercoiling, Chromosomes, Chromatids, Centromere,Nuclear Envelope, and Cancer.