5ab cell cycle & mitosis
- 1. 5A: CELL CYCLE & • Ident i fy and descr ibe the main phases of the cel l cycle • Ident i fy what form DNA is in dur ing di f ferent stages of the cel l cycle • Descr ibe 3 key events dur ing interphase • Ident i fy and descr ibe 4 main phases of mi tosis • Compare cytokinesis in plant and animals cel ls 5B: MITOSIS
- 2. THE CELL CYCLE The l ife of a cel l is described as the cel l cycle. Divided into three stages: INTERPHASE: Cells carry out normal functions MITOSIS: Duplication of genetic material and division of the nucleus CYTOKINESIS: Cell with 2 nuclei splits to form two identical daughter cells.
- 3. INTERPHASE Longest stage in the cel l cycle During this phase DNA is in the form of chromatin Divided into three par ts 1. Growth and Preparation: Cell increases in size while performing its usual functions 1. DNA Replication: DNA replicates making an exact copy of itself 1. Continued Growth and Preparation: Cell continues to grow and makes copies of its organelles
- 4. INTERPHASE – DNA REPLICATION
- 5. MITOSIS Shor test stage in the cel l cycle Contents of the nucleus divide resulting in two daughter nuclei that are identical to the original parent cel l
- 6. Impor tant structures: MITOSIS Spindle Fibers: Protein structures that move chromosomes during mitosis Centrioles (Animal cells only): Organelles that control the spindle fibers. *add label to animal cell diagram
- 7. Mitosis is divided into 4 stages (PMAT) 1. Prophase (early prophase & late prophase) 2. Metaphase 3. Anaphase 4. Telophase MITOSIS
- 8. MITOSIS - PROPHASE Early Prophase Dupl icated chromosomes condense into X-shape Nucleolus disappears Spindle fibers star t to form and spread across the cel l Centrioles move to opposite ends of the cel l Late Prophase Spindle fibers complete forming Spindle fibers attach to chromosomes at the centromere Nuclear membrane disappears
- 9. MITOSIS - METAPHASE Spindle fibers pul l chromosomes into a l ine across the metaphase plate at the center of the cel l
- 10. MITOSIS - ANAPHASE Spindle fibers contract and shor ten to separate sister chromatids and pul l to opposite ends of the cel l Once separated, sister chromatids are now considered daughter chromosomes
- 11. MITOSIS - TELOPHASE Final stage of mitosis A complete set of chromosomes is at each end of the cel l Nuclear membranes form around each set of chromosomes Nucleolus reappears Spindle fibers disappear There are two nuclei in one cel l
- 12. CYTOKINESIS Final stage of the cel l cycle Cel l with two nuclei spl its into two daughter cel ls New cel ls are identical to each other and to the parent cel l Cytokinesis is di f ferent in plant and animal cel ls due to the presence of a cel l wal l in plants. Animal cell: Cell membrane pinches together to separate two halves Plant cell: Cell plate forms along center of the cell