The Processes of Mitosis and Meiosis Note: Quiz over this material tomorrow (Thursday)

Mitosis Mitosis- is the process in which a cell divides to form TWO IDENTICAL CELLS. Follows specific order of events during the process of mitosis: –Interphase, Prophase, Metaphase, Anaphase, Telophase.

Step 1: Interphase Interphase is how the cell spends a majority of it’s life cycle (up to 90%). Normal functions. When getting ready to divide, the DNA winds up into chromosomes and duplicates but are NOT in X form yet.

Step 2: Prophase The newly created pairs are now visible as the X. Start moving to line up in the middle of the cell.

Step 3: Metaphase Chromosomes, paired up, line up in the middle of the cell “on top” of each other.

Step 4: Anaphase The paired chromosomes divide and pull to each side of the cell, which is beginning to elongate.

Step 5: Telophase Cell membrane starts pinching off. Chromosomes start unraveling.

Meiosis Process in which sex organs (ovaries and testes) produce FOUR genetically DIFFERENT daughter cells. Contains TWO cell divisions. Each daughter cell gets HALF the chromosomes as the parent cell.

Prophase I DNA winds up, forms into chromosome shapes. Each finds it’s “homologous pair”- it’s partner.

Metaphase I Line up “on top” of each other, but with it’s homologous partner next to it.

Anaphase I Sister chromatids (the X shape) move as a whole to one side or the other.

Telophase I Cell membrane begins to pinch off into 2 cells, each with the same number of chromosomes as parent cell.

Prophase II Start moving towards middle of cell (again).

Metaphase II Chromosomes aligned in middle “on top” of each other. Again.

Anaphase II Chromosomes pulled apart, move to opposite sides, again.

Telophase II Cell membrane closes off, chromosomes unravel back to DNA strands. Again.

Assignment With a partner, create a ‘mnemonic device’ to help you remember –The names of the phases and what occurs in each. –The differences between Mitosis and Meiosis. “Device” can be an acronym, lyrics, rap, poem, or similar thing which can be shared with others in the class.