PowerPoint Presentation

Cell Division: Mitosis

Licentious division - prostate cancer cells during division. CELL CYCLE VIDEO

https://www.youtube.com/watch?v=AhgRhXl7w_gInterphaseThree StagesG1: First growth phaseS: DNA replication (S = synthesis)G2: Second growth phaseAfter Interphase, Mitosis starts (cell division)

MITOSISMITOSIS IS JUST ONE SMALL PART OF THE ENTIRE CELL CYCLE.

Definition: Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets in two nuclei. KEY CONCEPT Cells divide during mitosis and cytokinesis.

Chromosomes condense at the start of mitosis.DNA wraps around proteins (histones) that condense it.

DNA doublehelixDNA andhistones ChromatinSupercoiledDNA

DNA plus proteins is called chromatin.One half of a duplicated chromosome is a chromatid.Sister chromatids are held together at the centromere.Telomeres protect DNA and do not include genes.

Condensed, duplicated chromosomechromatidtelomerecentromeretelomere

Parent cellcentriolesspindle fiberscentrosomenucleus withDNAInterphase prepares the cell to divide.During interphase, the DNA is duplicated.Mitosis and cytokinesis produce two genetically identical daughter cells.

Mitosis divides the cells nucleus in four phases.During prophase, chromosomes condense and spindle fibers form.

Mitosis divides the cells nucleus in four phases.During metaphase, chromosomes line up in the middle of the cell.

Mitosis divides the cells nucleus in four phases.During anaphase, spindle fibers pull sister chromatids to opposite sides of the cell.

Mitosis divides the cells nucleus in four phases.During telophase, new nuclear membranes form and chromosomes begin to uncoil.

During Cytokinesis the cell divides into two daughter cells

STAGES OF MITOSIS

INTERPHASEEARLY PROPHASELATE PROPHASEMETAPHASEANAPHASETELOPHASECYTOKINESIS (daughter cells formed)Why is it important for cells to make perfect copies of themselves? Their daughter cells need to be able to do the same thing they do. Muscle cells need to be muscle cells. Skin cells need to be skin cells, etc.

If DNA is copied or separated incorrectly, cell wont be able to function correctly. How do chromosomes move during mitosis?By using spindle fibers!

Lets take a look at this in more detailThe Spindle A spindle is a web type structure made up of microtubule fibers. It is essential for mitosis because it arranges the chromosomes into their correct positions in preparation for cell division.Mitotic center

MicrotubuleA cell at metaphasea spindle1717Click the return button to return to the prophase slide. Or the house button to return to the main menu.The purpose of the spindle is to organise the chromosomes during mitosis. It is a cradle of microtubule fibres which cause constriction around the centre of the cell, causing the cytoplasm to split.

Mitosis in ActionBlue shows DNA, green shows spindle fibers.interphaseearly anaphasemetaphaselate prophaseearly prophaseprometaphaselate telophaselate anaphase18Video of mitosis in process in actual cellshttps://www.youtube.com/watch?v=DD3IQknCEdcComparing plant/animal cell mitosis.While you observe the next set of images, try to identify how these processes differ in plant and animal cells. Why do you think the images are so different?Cytokinesis is different in plant and animal cellsIn animal cells, the membrane pinches closed.In plant cells, a cell plate forms.

In animal cells, a cleavage furrow forms and separates daughter cellsCleave furrow in a dividing frog cell.21The plant cell wall forces cytokinesis to play by different rules

22https://www.youtube.com/watch?v=aDAw2Zg4IgEhttps://www.youtube.com/watch?v=DD3IQknCEdcMicroscopy Video of Mitosis in an Animal CellMicroscopy Video of Mitosis in a Plant Cell