How many stages of cell division did you see? 3 Reasons Why Cells Reproduce Growth Repair Replacement Why Would a Cell Divide? As cells absorb nutrients and get larger, the volume of the cell increases faster than the surface area This means that a cell can no longer absorb nutrients and get rid of wastes fast enough to support its demands (volume) So whats a cell to do?Solution: divide in 2! Surface area for exchange not great enough to support cells needs Thanks to person who introduced me Explain presentation style Different, wacky, interactive Reason for madness- will be reviewed during implications May be asked to be an active participant May be asked to reinforce others Will be reinforced with candy Comments/questions welcomed throughout Reinforce me for doing well Have participants guess the number of new things they will learn today Cell division is a type of asexual reproduction. The Cell Cycle has 3 stages: 1) INTERPHASE 2) MITOSIS -Prophase -Metaphase -Anaphase -Telophase 3) CYTOKINESIS INTERPHASE Longest phase of the cell cycle (90% of time in Interphase) Cell grows & makes proteins Replicates its DNA and chromosomes Makes organelles for division, like centrioles INTERPHASE (for real) Animal Cell Plant Cell Chromosome Inside nucleus Genetic information (DNA) After S phase = 2 sister chromatids Review Question (whiteboard) Draw a chromosome on your whiteboard and circle 1 chromatid There are different # chromosomes for different species Which species do you think has the most chromosomes? Ewoks HumansShrimp Adders tongue ? Mitosis = Division of nucleus Prophase Metaphase Anaphase Telophase 1st Stage in Mitosis: PROPHASE Chromatin condenses into chromosomes. Nuclear envelope breaks down Centrioles separate to opposite sides of the cell Spindle begins to form between centrioles (made of microtubules) Prophase (for real) Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: 2nd Stage in Mitosis: METAPHASE Chromosomes line up at the center of the cell (meta means middle) Spindle fibers attach to each sister chromatid at its centromere Metaphase (for real) Plant Cell Animal Cell Photographs from: 3rd Stage in Mitosis: ANAPHASE Sister chromatids separate and the centromeres divide Pulled apart by the shortening of the spindle fibers Sister chromatids move to opposite poles of the cell Anaphase (for real) Plant Cell Animal Cell Photographs from: 4th Stage in Mitosis: TELOPHASE Chromosomes begin to uncoil and become chromatin Nuclear envelope begins to form around genetic material (chromatin). 2 distinct nuclei are forming! Telophase (for real) Plant Cell Animal Cell Photographs from: AFTER MITOSIS: CYTOKINESIS Cytoplasm pinches in half Two daughter cells are formed with identical genetic information. Cell cycle starts all over again! What happens if cells start to multiply uncontrollably? CANCER! uncontrolled cell growth leading to masses of cells called tumors Animal Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis Lets watch it in action! Can you tell when each stage begins? Narrate the Animation COOKIE MITOSIS!!! Cell Cycle Label each stage & place in the correct order!