KEY CONCEPT Cells divide during mitosis and cytokinesis.
DNA- double stranded molecule made of four different subunits of nucleotides (A,T,C,G) Chromosome- one long continuous thread of DNA Each body cell has 46 chromosomes in 23 pairs
Chromosomes condense at the start of mitosis. DNA wraps around proteins (histones) that condense it. DNA double helix DNA and histones Chromatin Supercoiled DNA
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. Old DNA New DNA Pg. 58
Interphase prepares the cell to divide (G1, S, G2) During interphase, the DNA is duplicated. Parent cell centrioles spindle fibers centrosome nucleus with DNA *Not part of mitosis
Mitosis divides a Somatic (body) cell’s nucleus in four phases. Prophase: chromosomes condense and spindle fibers form.
Metaphase: chromosomes line up in the middle of the cell.
Anaphase: sister chromatids separate to opposite sides of the cell.
Telophase: the new nuclei form and chromosomes begin to uncoil.
Cytokinesis differs in animal and plant cells. In animal cells, the membrane pinches closed. In plant cells, a cell plate forms.
How can you remember what goes first? Peter Made A Tiger Cry
A toe is part of your body Tip to Remember Mitosis = Mi “TOE” sis A toe is part of your body MITOSIS only occurs in your Somatic or BODY cells Every cell EXCEPT sperm and eggs