3Cell CycleG1 (Gap 1)- cells carry out normal metabolic activities for day to day functions.S (Synthesis)- DNA is replicated (duplicated, copied).G2 (Gap 2)- cell prepares for cell division by doubling cell organelles.
4MitosisA stage of the cell cycle that involves the division of the nucleus into two new nuclei that contain identical copies of the genetic information.Mitosis is divided into 4 stages based on the cellular events: Prophase, Metaphase, Anaphase, Telophase. (PMAT)If you include Interphase (IPMAT – I phoned mom and talked)
5Functions of Mitosis 1. Growth 2. Repair regenerate damaged tissues. 3. Regeneration of entire body parts simpler organisms.4. Maintenance of the body.Mitosis and cytokinesis occur in our body cells (aka somatic cells)
6Interphase Period of growth & development Hereditary information (DNA) copied (replicated / duplicated)Cells that do not divide (nerves) are always in interphase
16Cytokinesis (Cell Cutting) The division of the cytoplasm is know as cell cutting. This signals the end of Mitosis.After the cells membrane or wall forms a complete new barrier between the two sister cells. We would say cytokinesis has just occurred.
29Interphase Same as in Mitosis. Normal life cycle functions of the cell Divided into 3 stages:G1 (Gap 1)- Growth and developmentS (Synthesis Phase) - DNA is duplicatedG2 (Gap 2)- Organelles double in preparation for separation
30Prophase I DNA begins to shorten & thicken Centromeres form Now called chromatids/chromosomesCentromeres formNuclear membrane breaks apartSpindle fibers begin to formCROSSING OVER may occur.
38Cells carry one duplicated copy of a single chromosome. There are now two cells with each cell carrying only ½ the original chromosome number. (HAPLOID)Cells carry one duplicated copy of a single chromosome.They do not normally or necessarily carry the same genetic information as the parent cell or the sister chromatid.Because the chromosome number decreases this phase of meiosis is known as Reduction Division.
39Prophase II Similar to mitosis Starts with TWO cells instead of one Spindle fibers appearNucleus disappears (if reformed)
48In summary: Meiosis Two cells form during meiosis I In meiosis II, both of these cells form two cellsThe two divisions of the nucleus result in four sex cells (gametes)Each has one-half the number of chromosomes in its nucleus that was in the original nucleus