5.2 Mitosis and Cytokinesis Chapter 5 Cell Growth and Division Mr. Shilala DAHS

KEY CONCEPT Cells divide during mitosis and cytokinesis.

DNA and Chromosomes DNA is a double stranded molecule made of four subunits called nucleotides A chromosome is one long continuous thread of DNA Consists of numerous genes with regulatory information Your cells have 46 chromosomes If stretched out straight and laid end to end DNA in one cell would be about 10 feet long

Chromosomes condense at the start of mitosis. DNA is loosely organized during interpahse Looks like spaghetti DNA wraps around proteins (histones) that condense (shrink) it. DNA plus proteins is called chromatin DNA double helix DNA and histones Chromatin Supercoiled DNA

Telomeres protect DNA and do not include genes. Chromatid One half of a duplicated chromosome is a chromatid. Sister chromatids (identical chromatids) are held together at the centromere. Telomeres protect DNA and do not include genes. Prevent chromosomes from accidentally attaching to each other chromatid telomere centromere Condensed, duplicated chromosome

Interphase prepares the cell to divide. Mitosis and cytokinesis produce two genetically identical daughter cells. Parent cell centrioles spindle fibers centrosome nucleus with DNA Interphase prepares the cell to divide. During interphase, the DNA, or chromosomes, are duplicated.

Mitosis Mitosis divides the cell’s nucleus into 2 genetically identical nuclei in four stages Each has full set of DNA IPMAT Interphase Not part of mitosis Prophase Metaphase Anaphase Telophase

Prophase DNA and Proteins condense into Chromosomes Nuclear membrane breaks down, centrioles move to opposite poles and spindle fibers form

Metaphase Chromosomes line up in the middle of the cell. Spindle fibers attach to each chromosome

Anaphase Sister chromatids separate to opposite sides of the cell.

Telophase New nuclei form Chromosomes begin to uncoil Spindle fibers fall apart.

Cytokinesis Cytokinesis is the division of the cytoplasm into two cells In animal cells, the membrane pinches closed. In plant cells, a cell plate forms

Youtube Mitosis Video