The Cell CycleInterphase, Mitosis, and

Cytokinesis

10-2

Learning Goals

1. Summarize the cell cycle and what it results in.

2. Describe the function of the cell cycle in both a unicellular and multicellular organism.

3. Define chromosome and describe its parts.

4. Describe what happens to the chromosomes in each of the 6 steps of the cell cycle.

Cell Cycle

Cell Cycle - cell division that results in 2 new daughter cells that are an exact copy of the original (parent) cell.

The Cell Cycle

Three Main Stages: a) Interphase (95%)b) Mitosis (5%)c) Cytokinesis M Phase

M phase = cell division

Function Unicellular organisms

reproduce this way (asexual reproduction)

Multicellular organisms make new cells this way

Causes organisms to growTo replace old worn out cellsRepair damaged cells

Chromosomes Carry genetic information• DNA = genetic code

Every organism has a different # of chromosomes ex: humans have 46 (23 from

mom & 23 from dad)

One chromosome = pair of sister chromatids

Sister Chromatid = 1 copy of wound up DNA

Sister chromatids are held together by a centromere

centromere

Sister chromatid

Sister chromatid

Interphase

Prophase

Metaphase

The Cell Cycle MitosisAnaphase

Telophase

Cytokinesis

Interphaseoccurs before mitosis begins

Chromosomes, cytoplasm, and organelles are copied.

The cell grows

MitosisProphase

Metaphase Mitosis

Anaphase

Telophase

Prophase1st step in Mitosis

The genetic material (DNA) condenses into bundles called chromosomes.

Nuclear membrane disappears

Spindle fibers form

Centrioles move to opposite sides of the cell

Metaphase2nd step in Mitosis

The chromosomes line up along the middle of the cell

Spindle fibers attach to the centromeres of chromosomes

4.Anaphase3rd step in Mitosis

Sister chromatids separate and move to opposite sides of the cell

Telophase4th step in Mitosis

Nuclear membrane forms around each set of chromosomes

Chromosomes unwind into chromatin

Spindle fibers disappear

Now you try!

Identify the 4 steps of mitosis on the next slide (Hint: They are not in order)

Metaphase

Telophase

Anaphase

Prophase

Cytokinesisoccurs after mitosis

The cytoplasm splits in two

Result is two identical cells that have the same number of chromosomes as the original cell.

Learning Goals

1. Summarize the cell cycle and what it results in.

2. Describe the function of the cell cycle in both a unicellular and multicellular organism.

3. Define chromosome and describe its parts.

4. Describe what happens to the chromosomes in each of the 6 steps of the cell cycle.