Cell Division 7 th grade

Cell Division Animal Cell Plant Cell Photographs from:

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 Cycle Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Stage 1 - Interphase The period before a cell divides Cell grows to mature size Cell makes a copy of DNA Chromosomes 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 stage Cytoplasm divides into two Cell organelles are evenly distributed into the 2 new cells Two cells separate

Four Stages of Mitosis Prophase Mitosis begins (cell begins to divide) Centrioles (or poles) appear and begin to move to the opposite ends of the cell Spindle fibers form between the poles

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

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

Four Stages of Mitosis Telophase Two new nuclei form around the chromosomes Chromosomes appear as chromatin (threads) Mitosis ends Cytokinesis – cell splits

` 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.