Asexual Reproduction aka MITOSIS! In asexual reproduction, cell division results in 2 identical “daughter” cells being produced from a “parent” parent cell Each human cell has 46 chromosomes in its nucleus

Cell Cycle - Mitosis 10% of cell life cycle The cell undergoes cell division In humans, millions of cells divide every second to maintain a total of ~60 trillion cells - some divide once a day (skin & hair), others less often (stomach lining) and some not at all (nerve & muscle cells)

Stages of Mitosis Mitosis is a continual process, but we divide it into 4 phases Mitosis phases: 1.Prophase 2.Metaphase 3.Anaphase 4.Telophase

Mitosis 1. Prophase -chromatin condenses into distinct duplicated chromosomes -Nuclear membrane begins to disintegrate -In animal cells organelles called the centrioles move to opposite sides of the cell (“poles”) -Astral rays (microtubles) form around centrioles

Be sure to label: 1.Sister chromatids/ chromosomes 2.Centrioles 3.Astral rays 4.Nuclear memebrane Draw a prophase diagram Centriole s Astral Rays Made of 2 sister chromatids, attached by a centromere Nuclear membrane disintegrates

Early Prophase

Late Prophase

Mitosis Step 2: Metaphase -Chromosomes line up at equatorial plate and centromere attaches to spindle fibers that formed from elongated astral rays -At the end of this phase the centromere splits separating the sister chromatids -Nuclear membrane disappears

Be sure to label: 1.Centromere 2.Equatorial plate 3.Spindle fibers 4.Centriole Draw a diagram Centrioles Spindle Fibres Equatorial Plate Centromere

METAPHASE

Metaphase: Spindle Fibers

Mitosis Step 3: Anaphase -The spindle fibers contract, pulling the chromosomes (sister chromatids) to the opposite poles of the cell -Centromeres divide

Be sure to include: 1.Sister chromatids 2.Spindle fibres 3.Centromere 4.Centrioles Draw a diagram Centrioles Centromere is split

ANAPHASE

Mitosis Step 4: Telophase -Chromatids reach opposite poles; spindle and astral rays disappear -Chromosomes unwind back into chromatin -Nuclear membrane begins to reform -Cell membrane pinches in the middle to divide the cell = Cytokinesis

Cytoplasm begins to divide by forming a cleavage furrow at the equator and pinches off Forming 2 daughter cells, with genetic information identical to each other These cells will become the new parent cells Cytokinesis Cytokinesis in an animal cell Cleavage furrow

Draw a diagram Be sure to liable: Part A: Cleavage furrow Nuclear membrane Part B: Daughter cells Nuclear membrane Chromatin Daughter cells Chromatin Nuclear membrane

TELOPHASE

INTERPHASEPROPHASE

METAPHASETELOPHASE & CYTOKINESIS Metaphase plate Spindle Daughter chromosomes Cleavage furrow Nucleolus forming Nuclear envelope forming ANAPHASE

InterphaseProphase Metaphase AnaphaseTelophase

Animals Versus Plants There are 2 main differences in plant cell division 1.Plants do not contain centrioles -They contain microtubules that create many of the same proteins (spindles), they just don’t have the centrioles 2. Plants do not undergo cytokinesis - Instead a cell plate forms at the equator of the cell to form a new cell wall

Cytokinesis Animal Cytokinesis Plant Cytokinesis Cleavage furrow Cell Plate