Warm Up-Cell Division• K-W-L: Cell Division

Warm Up-Cell Cycle

1. Write “The Cell Cycle”

2. List the four phases of mitosis and their key word.

ACOS 5 & 9• SWBAT discuss “The Cell

Cycle”.

Mitosis Drawing• Page 98-99• Draw & label everything

except the pinkish-purple circles.

• Cell division allows growth, replaces worn out or damaged cells, and sometimes produces an entire new organism.

Cell Division and MitosisCell Division and Mitosis

11

• Multicellular organisms grow because cell division increases the total number of cells in an organism.

• Unicellular organisms reproduce an entire new organism by cell division.

Cell Division and MitosisCell Division and Mitosis

11

• The cell cycle is a series of events that takes place from one cell division to the next.

• Cell Cycle• Interphase• Mitosis• Cytokinesis

Length of Cycle

Cell Division and MitosisCell Division and Mitosis

11

• Interphase is the time during the cell cycle between cell division.

• During interphase a copy of the hereditary material must be made so that each of the two new cells will get a complete copy but no division takes place.

Interphase

Cell Division and MitosisCell Division and Mitosis

11

• A chromosome is a structure in the nucleus which contains hereditary material that duplicates during interphase.

Cell Division and MitosisCell Division and Mitosis

11

Interphase

Cell Division and MitosisCell Division and Mitosis

11

• After interphase, cell division begins.

Cell Division and MitosisCell Division and Mitosis

11

• When the nucleus is ready to divide, each duplicated chromosome coils tightly into two thickened, identicalstrands called chromatids.

• Mitosis is the process in which the nucleus divides to form two identical nuclei.

Mitosis

Cell Division and MitosisCell Division and Mitosis

11

Mitosis

Cell Division and MitosisCell Division and Mitosis

11

• The phases of mitosis in order are:

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

• Prophase = PrepareCell Division and MitosisCell Division and Mitosis

11

• Prophase is when the nucleus prepares to divide.

• Two small structures called centrioles move to opposite ends of the cell.

• Between the centrioles, threadlike spindle fibers begin to stretch across the cell.

• Metaphase = Middle• Metaphase is when the pairs of chromatids

line up across the middle of the cell.

• The centromere of each pair usually becomes attached to two spindle fibers, one from each side of the cell.

Cell Division and MitosisCell Division and Mitosis

11

• Anaphase = Apart• During anaphase the

spindle fibers shorten and each pair of chromatids begin to move apart.

Cell Division and MitosisCell Division and Mitosis

11

• The separated chromatids are now called chromosomes.

• During telophase the spindle fibers start to disappear, the chromosomes start to uncoil, and two nuclei form.

Cell Division and MitosisCell Division and Mitosis

11 Telophase = Two

CytokinesisCell Division and MitosisCell Division and Mitosis

11

• Cytokinesis is when the cell membrane pinches in the middle and the cytoplasm divides.

• After the nucleus has divided, the cytoplasm separates and two new cells are formed.

• Following cytokinesis new cells begin interphase again.