Mitosis

Asexual cell division!!

Begins in the nucleus of a cell.

How does asexual reproduction occur in humans?

• MITOSIS– Skin cells – Liver cells

MITOSIS1. Occurs in somatic

(body) cells.

2. Does not create sperm and egg.

3. Creates exact copies of a parent cell

4. Used to repair wounds and grow from a zygote to a person.

5. DNA duplicates itself and then the cell divides

MITOSIS

Mitosis and the Cell CycleRemember the letters: I P M A T

These letters will help you to remember the order of the 5 stages of the Cell Cycle:1. Interphase

1. Prophase

1. Metaphase

1. Anaphase

1. Telophase

Interphase:Called Resting phase

Cell is NOT dividing

Performs life functions

- Cell grows

- Copies all organelles

- Copies DNA

1. Interphase: “Prep Period”

- Cell preparation for cell division

- Two Major Events:

1. Cell increases in size

2. DNA and organelles

are replicated (copied)

Chromatin: are chromosomes when they are NOT distinguishable and they look like spaghetti.

Interphase has 3 parts (takes up about 90% of the cell cycle)

1. G1 - growth one phase (organelles grow)

2. S - synthesis phase (replication of chromosome material)

3. G2 - growth phase two (more organelle and cell growth)

MITOSIS- Has 4 phases - Prophase, Metaphase, Anaphase, Telophase

Prophase:- DNA changes from chromatin to chromosome

- Nucleus breaks apart with nucleolus and nuclear membrane disappears

- Centrioles begin to separate and move to poles

- Spindle fibers form to connect centrioles

Terms:• Chromatid: each chromosome strand

• Centromere: (kinetochore): holds the chromatids together

Metaphase: (M is for Middle)

• Chromosomes line up along the equator (middle)

• Chromosomes attach to the spindle fibers at their centromeres

Anaphase: ( A is for Away)• Spindle fibers pull chromosomes apart and

move each half of the chromosomes to opposite poles

Telophase: the reverse of interphase

• Nuclear membrane form around each set of chromosomes

• DNA changes from chromosomes to chromatin

• Spindle fibers disappear

Plant cells -

CYTOKINESIS

• the cell membrane pinches in to split the parent cell into two daughter cells.

Compare & Contrast Mitosis in Plants and Animals

Plant vs Animal

Plant Animal

No centrioles = no spindle fibers

Centrioles

No astray rays b/c there are no centrioles

Astray rays

Forms a cell plate Cytokinesis to pinch in cell membrane

Asexual Reproduction: Mitosis

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