9Condensed, duplicated chromosome or sister chromatids centromereCondensed, duplicated chromosome or sister chromatidsHolds the duplicated chromosome togetherG2 phase: Cell gets ready for mitosis
10***DNA is in the form of Chromatin (ball of DNA) INTERPHASE***DNA is in the form of Chromatin (ball of DNA)Centrioles copies are made1. More cytoplasm- cell grows.2. DNA is being replicated.3. More organellesThe cell is getting ready for MITOSIS, cell division.
11_______________________________________ Steps of MitosisProphaseMetaphaseAnaphaseTelophase_______________________________________PMAT
12X 3. Centrioles move apart. 2. Nuclear Membrane Breaks down Mitosis – PROPHASE4. Fibers form3. Centrioles move apart.X1.Chromatin forms visible chromosomes2. Nuclear Membrane Breaks down
13PROPHASE 1. DNA 2. Nuclear Membrane 3. Centrioles 4. Fibers Move apart from one another in opposite directionsBegins to break downForm between centriolesChromatin condenses into visible chromosomes
144.THE NUCLEAR MEMBRANE IS NO LONGER PRESENT 2. Spindle fibers connect to the sister chromatidsMitosis – Metaphase4.THE NUCLEAR MEMBRANE IS NO LONGER PRESENTX3. Sister chromatids are lined up along the middle of the cell.1. Centrioles move to opposite poles.
15METAPHASE 1. Centrioles 2. Fibers 3. DNA 4. Nuclear Membrane Sister chromatids are pulled to the middle of the cellContinue to move to opposite ends of the cellAttach to the sister chromatids.Is completely gone
16Mitosis – ANAPHASE2.Centrioles begin to pull the chromosomes toward the opposite sides of the cell.>1. Sister Chromatids separate
17ANAPHASE 1.Sister Chromatids 2.Fibers 3.Centrioles 4.Nuclear Membrane Pulled apartEach chromatid is separate from its “sister”Still at opposite sides of the cellPull each chromatid toward opposite ends of cellIs still gone
18> 2. Nuclear Membrane begins to reappear Mitosis – TELOPHASE>2. Nuclear Membranebegins to reappear3.Cell Membrane pinches at center4. Fibers begin to disappear1.Chromosomes are at opposite sides of the cell
19TELOPHASE 1.Sister Chromatids 2.Nuclear Membrane 3.Cell Membrane 4.FibersEach end of cell has a complete set of chromosomes.Begins to pinch at the center, forming two new identical cellsBegin to disappearBegins to reform around the sets of chromosomes
20Cell Membrane splits into two new identical cells CYTOKINESISCell Membrane splits into two new identical cells
22ANAPHASE METAPHASE TELOPHASE PROPHASE Phases of Mitosis: Prophase
23So What Does The Process of Mitosis Look Like? Another Animation Control of thecell cycleCell Cycle of MitosisInteractive reviewof mitosis fromClasszone.comVideo clips
24Plant Cell vs. Animal Cell MITOSISPlant Cell vs. Animal CellThe process is VERY SIMILAR in each type of cell.There are only 2 differences:Plant cells do not have centriolesThe cell membrane cannot pinch because of the cell wall.Instead a cell plate forms between the 2 nuclei division.
25Changes in the Rate of Mitosis Changes often occur in the growth rate of cells.Faster Rate of Mitosis:CANCER_______________________Slower Rate of Mitosis:AGING_______________________
26Regulation of the Cell Cycle External factorsPhysical signal – cell to cell contact. Once a cell touches another cell it stops dividing.When cells fail to respond to the external signal, the cells continue to divide uncontrollably and form clumps.Tumor – is a clump of cancer cells.Benign – tumor is harmless, the cells are clustered together tightly and can be removed.Malignant – tumor is bad, the cells can break away and be carried to other parts of the body.When a tumor has metastasized, it means the cancer cells have spread to other parts of the body.
27Why are tumors Harmful?Cancer cells do not perform the specialized functions needed by the body.In the lung – cancer cells do not exchange oxygen and carbon dioxide.In the brain – they do not transmit the messages needed to interpret information to the bodyCan exert great pressure on surrounding organs.
28Cancer 1. CHEMICALS Chemicals used on household items Drugs Carcinogen – a substance known to produce or promote the development of cancer cells.1. CHEMICALSChemicals used on household itemsand/or pesticides, tobaccoDrugsNuclear Wastes2. RADIATION3. SOME VIRUSESHPVSunX-Rays
30Meiosis (cell reproduction) Cuts chromosome number in half.Creates haploid cells.Creates sperm and eggSpermatogenesis – the creation of spermOogenesis – the creation of ova (egg)Meiosis (cell reproduction)
31Sperm or Eggs In males: These cells develop into 4 individual sperm that are genetically different from the parent cell.In females:These cells would have developed into 3 small polar bodies which will die and only 1 large egg.(THIS IS DUE TO AN UNEVEN DIVISION OF CYTOPLASM DURING MEIOSIS)
32Fertilization: Union of sperm and Egg Creates a zygote Re-establishes the full number of chromosomes2 chromosomes2 chromosomes4 chromosomes32
33Mitosis vs. Meiosis To make sperm and eggs with Occurs in sex cells For growth and to replace old, worn out cells.Occurs in body cellsTwo cells from 1 cellIdentical cells to the parent cell.Same number of chromosomes as the original (2N) - diploidOne division of the nucleus.To make sperm and eggs withOccurs in sex cellsFour cells from 1 cellGenetically different from the parent cell.Half the number of chromosomes (1N) - haploidTwo divisions of the nucleus.33