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!