The document defines key terms related to the cell cycle such as chromosomes, sister chromatids, and centromere. It then explains the main stages of the cell cycle as interphase, mitosis, and cytokinesis. Interphase is further broken down into the G1, S, and G2 phases where the cell grows and prepares for division. Mitosis is described as having four phases - prophase, metaphase, anaphase, and telophase - where the cell nucleus divides to produce two daughter cells each with a full set of chromosomes.

1. Mr. Nettles Biology I: Cell Growth and Reproduction (Part 2)

2. Today’s Objectives I will define: chromosomes , sister chromatids , and centromere. I will explore the stages of the cell cycle. I will explore the phases of mitosis.

3. Agenda – Thurs., Sept. 22, 2011 Warm-Up Presentations (Homework from last night) Lesson Wrap-Up

4. Warm-Up Mitosis is a form of ________________ reproduction. Eukaryotes reproduce by _________________. Prokaryotes reproduce by ________________.

5. Research: The Cell Cycle Choose one of the following stages of the cell cycle: G1 phase, S phase, G2 phase, M phase, or Cytokinesis. Use the internet to research information about the stage that you have chosen. Write four interesting things about what you read: What is it? (The definition) What happens? How long does it happen? What’s used? (What special cell parts or organelles are involved)

6. The Cell Cycle A process by which cells: Grow make copies of chromosomes divide into new daughter cells copyright cmassengale

7. The Cell Cycle Has three parts: Interphase Mitosis Cytokinesis copyright cmassengale

8. Interphase G1 Phase = “gap 1” phase First growth stage Cell gets bigger Cell prepares to copy its DNA

9. Interphase

10. The set of 46 human chromosomes

11. Sister Chromatids = the two identical parts on a chromosome Centromere = the middle part that holds the sister chromatids together

12. Interphase G2 Phase = “gap 2” phase Second growth stage Organelles needed for Mitosis are formed Centrioles and Spindle Fibers

13. Interphase Summary G1 : cell growth S phase : DNA is copied G2 : cell prepares for division

14. M Phase (Mitosis) One division of the cell nucleus to produce two new daughter cells Has four phases (PMAT): P rophase M etaphase A naphase T elophase

15. 1. PROPHASE Chromosomes appear Centrioles move to opposite ends of the cell Chromosomes attach to the spindle Nucleolus and nuclear membrane breaks down

16. 2. METAPHASE Chromosomes line up at the center or (middle)

17. 3. ANAPHASE Centromeres split Sister chromatids separate to form individual chromosomes Anaphase ends when the movement of chromosomes stops

18. 4. TELOPHASE Chromosomes uncoil into chromatin Nuclear membrane reforms Spindle breaks apart

19. 5. CYTOKINESIS The cytoplasm of the cell divides Forms two daughter cells that are exactly like the parent cell (each have one complete set of chromosomes)

20. Wrap-Up Which part of interphase involves copying DNA ? Which stage of Mitosis involves chromosomes lining up at the middle ? What are chromosomes made up of?