Mitosis Cell Division

First, Let’s Review ….

Cell Reproduction Let’s Review – All cells are derived from pre-existing cells New cells are produced for growth and to replace damaged or old cells

Types of Cell Reproduction Asexual Reproduction - a single cell divides to make 2 new identical cells Eg. Mitosis Sexual Reproduction - two cells (egg & sperm) that are NOT identical to the original cells unite to form a zygote Eg. Meiosis

How does DNA make more DNA? DNA Replication How does DNA make more DNA?

Two new, identical DNA strands DNA Replication DNA must be copied or replicated before cell division Each new cell will then have an identical copy of the DNA Original DNA strand Two new, identical DNA strands

The Cell Cycle

Cells prepare for Division Cell Divides into Identical cells Cell Cycle DNA Copied Cells prepare for Division Cells Mature Daughter Cells Cell Divides into Identical cells

Two identical copies of DNA Interphase Cell carries on its normal activities Makes more cytoplasm & organelles DNA is copied (“replicated”) All cell structures needed for division are made (e.g. centrioles) Original DNA Two identical copies of DNA

Mitosis

Mitosis has 4 Stages 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase

Vocabulary Chromosomes – threads of genetic material Chromatids – a copied chromosome Centromere – “belt” that holds chromatids together Spindle fiber – “string” that attaches to chromosome Centrioles – produces the spindle fiber Nuclear membrane – envelope around the nucleus

Chromosomes in Dividing Cells Duplicated chromosomes are called chromatids & are held together by the centromere Called Sister Chromatids

Prophase

Prophase Spindle fibers forms from centrioles Nuclear membrane is broken down Spindle fibers attach to the centromere of each chromosome

Spindle Fiber attached to Chromosome

Metaphase

Metaphase Chromosomes move to the center of the cell Chromosomes are now lined up at the equator (Middle = Metaphse) Equator of Cell Pole of the Cell

Metaphase Spindle Fibers Chromosomes lined at the Equator

Chromosomes at Equator Metaphase Chromosomes at Equator

Anaphase

Anaphase Sister chromatids are pulled apart to opposite poles of the cell by spindle fibers

Sister Chromatids being separated Anaphase Sister Chromatids being separated

Telophase

Telophase Sister chromatids at opposite poles Spindle disassembles Nuclear envelope forms around each set of sister chromatids CYTOKINESIS occurs

Cytokinesis Means division of the cytoplasm Division of cell into two, identical halves called daughter cells

Cleavage furrow in animal cell Cell plate in plant cell Cytokinesis Cleavage furrow in animal cell Cell plate in plant cell

Daughter Cells of Mitosis Have the same number of chromosomes as each other and as the parent cell from which they were formed

Identical Daughter Cells Chromosome number the same, but cells smaller than parent cell

Review of Mitosis

P.M.A.T Key Words Prophase – Plug together Metaphase – Middle Anaphase – Away Telophase - Terminated

Name the Mitotic Stages: Interphase Name this? Prophase Telophase Name this? Metaphase Anaphase

Name each stage as you see it occur? Mitosis Animation Name each stage as you see it occur?

Chromosomes during Metaphase of mitosis Cell Division Chromosomes during Metaphase of mitosis Cytokinesis Anaphase Prophase Metaphase Telophase

Telophase & Cytokinesis Identify the Stages ? Prophase ? ? ? Metaphase Anaphase Prophase ? ? ? Telophase & Cytokinesis Anaphase Telophase

Locate the Four Mitotic Stages in Plants Anaphase Telophase Metaphase Prophase