CELL GROWTH & REPRODUCTION

Why are cells so small? Small cells are efficient because they have a smaller surface to volume ratio Exchange of oxygen, food and waste across the membrane is more efficient in small cells

Cell Vocab To Know DNA- genetic material Chromatin= loose DNA, like pasta Chromosomes = condensed chromatin, they form when cell is ready to divide, look like an X Chromosomes are made up of 2 sister chromatids held together in the middle by the centromere

The Life of a Cell Cell Cycle = sequence of growth & division of a cell 1. Interphase 2. Cell Division Mitosis Cytokinesis

1. Interphase Cell grows, majority of a cell’s life. Has 3 parts: G1: Cells grow and makes proteins S: Chromosomes containing DNA are replicated (copied) G2: Cell prepares for division

2. Cell division Mitosis- cell division creates 2 daughter cells w/ identical DNA Divided into 4 phases Prophase Metaphase Anaphase Telophase Cytokinesis

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1. Prophase Chromatin thickens and forms into visible chromosomes Nuclear Envelope & Nucleolus break down Centrioles (poles) at opposite ends of cell start sending out spindle fibers (fingers) between them

2. Metaphase Chromosomes line up in the center of the cell Spindle Fibers attach to the centromere of each chromosome and pulls them in the middle

3. Anaphase Sister chromatids are pulled to the opposite ends (poles) of the cell

4. Telophase Nuclear Envelope & Nucleolus re-form Chromosomes appear as chromatin again Mitosis ends 2 daughter cells with identical DNA

Cytokinesis Division of the cytoplasm Cleavage (pinch) in animal cells Cell Plate (new wall) in plant cells

30 Seconds 10 Time’s Up! 3 Minutes 1 Minute 4 Minutes 1 2 5 2 Minutes Bellringer Tue, 11/24 Please list the 4 phases of mitosis. PMAT! A chromosome is made up of__________ Reminders: LAB FEE NOW! HW #12 due Wed! 30 Seconds 10 Time’s Up! 3 Minutes 1 Minute 4 Minutes 1 2 5 2 Minutes 8 9 7 6 4 3

Interphase Prophase Metaphase Anaphase Telophase