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.

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.

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• 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.

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• 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

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• 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

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

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Interphase

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• After interphase, cell division begins.

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• 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

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Mitosis

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• The phases of mitosis in order are:

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

• Prophase = PrepareCell Division and MitosisCell Division and Mitosis

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• 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.

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• Anaphase = Apart• During anaphase the

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

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• 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

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CytokinesisCell Division and MitosisCell Division and Mitosis

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• 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.