6. Diagram and list events of the cell cycle (interphase and mitosis) 7. Describe haploid, diploid, somatic cells, germ cells/gametes. (know human's diploid and haploid count) 8. Visually identify the stages of mitosis in a cell (prophase, metaphase, anaphase and telophase) 9. Determine how the process of meiosis works. 10. Differentiate between mitosis and meiosis. eek 8

### 6. Diagram and List Events of the Cell Cycle **Diagram of the Cell Cycle:** ``` +-------------------------------------------------------------+ | Interphase | | (G₁ phase -> S phase -> G₂ phase) | +-------------------------------------------------------------+ ↓ Mitosis (M phase) +-------------------------------------------------------------+ | Prophase → Metaphase → Anaphase → Telophase (+ Cytokinesis)| +-------------------------------------------------------------+ ``` **Events:** - **Interphase:** - **G₁ phase:** Cell growth and normal metabolic functions. - **S phase:** DNA replication where the genetic material is duplicated. - **G₂ phase:** Further cell growth and preparation for division. - **Mitosis (M phase):** - **Prophase:** Chromosomes condense, the nuclear membrane begins to disintegrate, and the spindle apparatus forms. - **Metaphase:** Chromosomes line up along the metaphase plate (equatorial plane). - **Anaphase:** Sister chromatids separate and move toward opposite poles of the cell. - **Telophase:** Chromosomes de-condense, the nuclear envelope re-forms, and the cell begins to split. - **Cytokinesis:** Division of the cytoplasm, resulting in two daughter cells. ### 7. Describe Haploid, Diploid, Somatic Cells, Germ Cells/Gametes - **Diploid Cells (\(2n\)):** Cells containing two complete sets of chromosomes. In humans, the diploid number is \(46\). - **Haploid Cells (\(n\)):** Cells containing one complete set of chromosomes. In humans, the haploid number is \(23\). - **Somatic Cells:** These are body cells (e.g., skin, muscle, liver) and are diploid (\(2n\)). - **Germ Cells/Gametes:** Reproductive cells (e.g., sperm and egg) that are haploid (\(n\)). They fuse during fertilization to re-establish the diploid number in the zygote. ### 8. Visually Identify the Stages of Mitosis in a Cell - **Prophase:** - Chromosomes condense and become visible as distinct structures. - The nuclear envelope begins to break down. - The mitotic spindle starts to form. - **Metaphase:** - Chromosomes align along the metaphase plate (center of the cell) with their kinetochores attached to spindle fibers coming from opposite poles. - **Anaphase:** - Sister chromatids separate and are pulled toward opposite poles of the cell. - **Telophase:** - Chromatids reach the poles and begin to de-condense. - Nuclear envelopes re-form around each set of chromosomes, signaling the near completion of cell division. - Cytokinesis usually follows, splitting the cell into two daughter cells. ### 9. Determine How the Process of Meiosis Works **Meiosis** is a two-stage division process that produces four genetically distinct haploid cells. It is critical for sexual reproduction. The stages are divided into two parts: Meiosis I and Meiosis II. - **Meiosis I (Reductional Division):** - **Prophase I:** Homologous chromosomes pair up and undergo crossing-over (exchange of genetic material), leading to genetic recombination. - **Metaphase I:** Paired homologous chromosomes line up at the metaphase plate. - **Anaphase I:** Homologous chromosomes (each still composed of two sister chromatids) are separated and pulled to opposite poles. - **Telophase I and Cytokinesis:** Two daughter cells are formed, each with half the number of chromosomes (\(n\)) but each chromosome still consists of two sister chromatids. - **Meiosis II (Equational Division):** - Resembles mitosis, where the sister chromatids of each chromosome separate. - **Prophase II, Metaphase II, Anaphase II, Telophase II:** The sister chromatids are divided, resulting in four genetically distinct haploid cells. ### 10. Differentiate Between Mitosis and Meiosis - **Purpose:** - **Mitosis:** Produces two identical daughter cells for growth, repair, and asexual reproduction. - **Meiosis:** Produces four genetically diverse gametes for sexual reproduction. - **Number of Divisions:** - **Mitosis:** One division cycle producing two daughter cells. - **Meiosis:** Two successive division cycles (Meiosis I and II) producing four daughter cells. - **Chromosome Number:** - **Mitosis:** Daughter cells are diploid (\(2n\)) in organisms that are normally diploid. - **Meiosis:** Daughter cells are haploid (\(n\)); essential for maintaining the chromosome number after fertilization in sexually reproducing organisms. - **Genetic Variation:** - **Mitosis:** No crossing-over occurs; daughter cells are genetically identical to the parent cell. - **Meiosis:** Crossing-over during Prophase I introduces genetic variation among gametes. - **Occurrence:** - **Mitosis:** Occurs in somatic cells. - **Meiosis:** Occurs in germ cells.