Asexual Reproduction aka MITOSIS In asexual reproduction cell

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, 6. 0 x 10 13 - some divide once a day (skin & hair and stomach) and some not at all (nerve & muscle cells)

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

1. Prophase -chromatin condenses into distinct duplicated chromosomes -Nuclear membrane begins to disintegrate -In animal cells organelles called 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 Centrioles Astral Rays Made of 2 sister chromatids, attached by a centromere Nuclear membrane disintegrates

Early Prophase

Late Prophase

Step 2: Metaphase -Chromosomes line up at equator and centromere attaches to spindle fibers At the end of this phase the centromere splits separating the sister chromatids Nuclear membrane disappears

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

METAPHASE

Metaphase: Spindle Fibers

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

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

ANAPHASE

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 begin Cytokinesis

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

TELOPHASE

INTERPHASE PROPHASE

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

Interphase Metaphase Prophase Anaphase Metaphase Telophase

Animals Versus Plants There are 2 main differences in 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 Cleavage furrow Cell Plate Plant