Presentation on theme: "KEY CONCEPT Cells divide during mitosis and cytokinesis."— Presentation transcript:
1 KEY CONCEPT Cells divide during mitosis and cytokinesis.
2 One half of a duplicated chromosome is a chromatid. One long continuous thread of DNA coiled around histones (proteins) is called chromatin.chromatidcentromeretelomereCondensed, duplicated chromosomeOne half of a duplicated chromosome is a chromatid.Sister chromatids are held together at the centromere.Telomeres protect DNA and do not include genes.
3 Chromosomes condense at the start of mitosis. DNA wraps around proteins (histones) that condense it.DNA double helixDNA and histonesChromatinSupercoiled DNA
4 1.Interphase prepares the cell to divide. B. Mitotic Phase- Mitosis and cytokinesis produce two genetically identical daughter cells.Parent cellcentriolesspindle fiberscentrosomenucleus withDNA1.Interphase prepares the cell to divide.DNA is duplicated.
5 Cell structures and mitosis Centrosomes-organelle that is the main microtubule organizing center.Aster-cellular star shaped structure that forms around the centrosome-made of microtubulesEquator-mid section of the dividing cellCleavage furrow - indentation that begins the formation of the new cell membraneCell plate- the new cell wallKinetorchore fibers- attachment points on the centromere where the chromosomes are held together to make an XSpindle- fibers that separate the chromosomesMicrotubules-hollow, protein fibers and rods.Cytokinesis-division of the cytoplasm results two daughter cells.
6 2.During prophase, chromosomes condense, nuclear membrane, nucleus, and nucleolus disappear, spindle fibers form, centrioles make spindle fibers
7 3.During metaphase- spindle fibers randomly align sister chromatids in the middle of the cell (equator)
8 4.During anaphase- spindle fibers retract and pull the sister chromatids opposite sides of the cell (poles)
10 6.Cytokinesis-division of the cytoplasm In animal cells, the membrane pinches closed at a point called cleavage furrow.In plant cells-vacuoles join together and form a cell plate.Result-2 identical daughter cells with identical copies of genetic material-DNA