Cell Division7th grade

Cell DivisionAnimal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Cell Cycle

• Cell Cycle is a regular sequence of growth and division a cell undergoes

• 3 Main Stages• 1. Interphase • 2. Mitosis (Prophase, Metaphase,

Anaphase & Telophase)• 3. Cytokinesis

Animated Mitosis Cyclehttp://www.cellsalive.com/mitosis.htm

• Interphase

• Prophase

• Metaphase

• Anaphase

• Telophase

• Cytokinesis

Stage 1 - Interphase

The period before a cell dividesCell grows to mature sizeCell makes a copy of DNAChromosomes appear as threadlike coils

(chromatin) at the start, but each chromosome and its copy (sister chromosome) change to sister chromatids at the end of this phase

The cell spends MOST of its life here

Stage 2 - Mitosis

The stage of the cell’s cycle when the cell’s nucleus divides into two nuclei

During mitosis:◦One copy of DNA is given to each daughter cell◦Four stages – Prophase, Metaphase, Anaphase

& Telophase

Stage 3 - Cytokinesis

Final stageCytoplasm divides into twoCell organelles are evenly distributed

into the 2 new cellsTwo cells separate

Four Stages of MitosisProphase

Mitosis begins (cell begins to divide)Centrioles (or poles) appear and begin to

move to the opposite ends of the cellSpindle fibers form between the poles

Four Stages of MitosisMetaphase

Chromatids (or pairs of chromosomes) attach to the spindle fibers and line up in the middle of dividing cell

Four Stages of MitosisAnaphase

Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell

Four Stages of MitosisTelophase

Two new nuclei form around the chromosomes

Chromosomes appear as chromatin (threads)

Mitosis endsCytokinesis – cell splits

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Key Terms - Use your textbook to define the key terms of Cell Division – Ch. 3, Sec. 5, p. 95

◦Cell cycle◦Interphase◦Replication◦Mitosis◦Chromosome◦Cytokinesis

Key Terms

◦Cell cycle – The regular sequence of growth and division that cells undergo

◦Interphase – The first stage of the cell cycle. During interphase the cell grows to its mature size, makes a copy of its DNA, and prepares to divide

◦Replication – The process where the cell makes a copy of the DNA in its nucleus

Key Terms

◦Mitosis – The second stage of the cell cycle. During mitosis, one copy of the DNA is distributed into each of the two daughter cells

◦Chromosome – double rod of condensed chromatin

◦Cytokinesis – the final stage of the cell cycle. During cytokinesis, the cytoplasm divides, distributing the organelles into each of the two new cells.