5.2 Mitosis

Some Terms You Need to Understand Chromosome– long strand of DNA Chromosomes condense at the beginning of Mitosis DNA will wrap around histones, which condenses it.

Chromosome Structure DNA double helix DNA and histones Chromatin Supercoiled DNA

Chromatin—When DNA wraps around histones Chromatid– 1 half of a duplicated chromosome. Duplicated chromosome—two sister chromatids joined together at the cnetromere Centromere—holds sister chromatids together Telomere—ends of chromosome—keeps chromosome from unraveling and keeps you from losing DNA

Types of Cells Germ cells Somatic cells: Become egg and sperm Body cells—every cell other than sex cells

Haploid vs. Diploid Diploid: Haploid: Contains two complete sets (2n) of chromosomes Reproduce by mitosis Makes daughter cells completely identical to parent cells Skin, blood, muscles Haploid: Half the number of chromosomes (n) as diploid Result from meiosis Sperm and ova

The Beautiful Process Called The Cell Cycle Interphase prepares the cell to divide Time for duplication of organelles and DNA replication 2 full sets of DNA that are large enough to divide G1, Synthesis, G2 G1—after cell division, matures and grows, makes cytoplasm and organelles, carries out normal functions S—DNA replication G2—makes all structures needed to survive

Cell Division in Prokaryotes Prokaryotes have no nucleus Divide asexually by binary fission Chromosome (circular) copies itself and becomes 2x the original size Cell wall forms between chromosomes and parent cell splits in two Results in 2 identical daughter cells

Other forms of Asexual Reproduction Budding Offspring is a growth off of the parent Bud breaks away from parent Fragmentation Parent organism breaks into pieces that develop into offspring Parthenogenesis Ovum becomes fertilized—no sperm is present to fertilize—mice, komodo dragons, Burmese pythons, cape bee, freshwater snails, turkeys

Cell Division in Eukaryotes MITOSIS!!!!!!!!!!!!!!!!!!!!!!!

Mitosis PMAT Prophase—chromatin condenses to chromosome. Nuclear envelop breaks down, nucleolus disappears, centromeres and centrioles start to migrate to opposite sides Spindle fibers grow from centrioles and radiate to center of cell.

PMAT Metaphase– spindel fibers attach to protein structure on centromere Align chromosome along the equator of cell

PMAT Anaphase—sister chromatids separate Spindle fibers begin to shorten This pulls sister chromatids away from each other They move to opposite sides of the cell

PMAT Telophase—complete set of identical chromosomes are at each pole of the cell Nuclear membrane starts to form Chromosomes start to uncoil Spindle fibers fall apart

The Final Part CYTOKINESIS—divides cytoplasm into 2 cells and goes through the cycle again.

Mitosis at a Glance

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