Mitosis/ Meiosis SC.912.L describe the specific events that occur in each of the stages of the cell cycle (which include the phases of mitosis:) – interphase (Gap 1, Synthesis, Gap 2) – prophase – metaphase – anaphase – telophase – cytokinesis explain how new cells are created through mitosis explain why maintaining chromosome number during asexual reproduction is important SC.912.L.16.8 describe cancer as uncontrolled cell growth that may have resulted from mutations affecting cell cycle-regulating proteins SC.912.L describe the process of meiosis, including independent assortment and crossing over explain how reduction division results in the formation of haploid gametes or spores SC.912.L16.17 differentiate the processes of mitosis and meiosis model or diagram the process of mitosis and meiosis explain how sexual and asexual reproduction may contribute or limit genetic variation

Gap 1 (G1)- cells perform normal function, cells grow and replicate organelle; checkpoint Synthesis (S)- cell synthesizes a whole new copy of DNA (in nucleus in eukaryotic cells), at end of stage there are two copies of DNA Gap 2 (G2)- additional growth; second checkpoint Mitosis (M)- two parts: mitosis and cytokinesis – Mitosis is division of cell nucleus and DNA inside – Cytokinesis is division of contents (cytoplasm) Interphase Cell Cycle

What are the stages of mitosis and how do they produce identical copies of cells? Mitosis= cell division Before Cell Division ▫ Interphase- Chromosomes duplicate, cell prepares for mitosis Mitosis Stages ▫ Prophase- Chromosomes condense ▫ Metaphase- Chromosomes meet in the middle ▫ Anaphase- Chromosome pull away ▫ Telophase- cell separating ▫ Cytokinesis- Separation of cells is complete PMAT

How does mitosis maintain the chromosome number in the parent cells? The chromosomes duplicate (make a copy of) themselves before cell division or mitosis. – Occurs in interphase, when the cell is preparing to divide.

How does mitosis allow for asexual reproduction? Mitosis is making an exact copy of the cell. In my mitosis there no exchange or recombination of DNA. – Examples of Asexual Reproduction: Cutting off a piece of plant and replanting it, budding, and binary fission in bacteria.

What are the steps in meiosis that result in the formation of haploid gametes? Haploid= half the number of chromosomes ▫ Ex: Human gametes are haploid (23 chromosomes) The chromosomes in the original cell duplicate and the cell then goes through two cell divisions.

Why is meiosis necessary for sexual reproduction and how does it allow for creating genetic diversity? Meiosis creates gametes. Each cell created as a result of meiosis are different because of independent assortment and crossing over

How are mitosis and meiosis similar but different? MitosisMeiosis Starts with 1 diploid cell Ends with 2 diploid cells Starts with 1 diploid cell Ends with 4 haploid cells Occurs in somatic cellsCreates gametes (sex cells) Creates cells that are identical Creates cells that are genetically different

How can independent assortment and crossing over occur during meiosis? Both crossing over and independent assortment results in genetically unique gametes Crossing over -the exchange of chromosome pieces between homologous chromosomes. –.

Independent Assortment Independent assortment- Chromosomes can arrange themselves independently during meiosis.

Cancer Cancer- uncontrolled cell growth that may have resulted from mutations affecting cell cycle- regulating proteins