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Mitosis. What is Mitosis?. Mitosis : Cell division involving somatic (non-sex) cells Involves only diploid cells End Result : Two genetically identical “daughter cells”. The Cell Cycle. Defined : Repeating set of events in the life of a cell 1) Interphase G1, S, G2 2) Prophase
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What is Mitosis? • Mitosis: Cell division involving somatic (non-sex) cells • Involves only diploid cells • End Result: Two genetically identical “daughter cells”
The Cell Cycle • Defined: Repeating set of events in the life of a cell • 1) Interphase • G1, S, G2 • 2) Prophase • 3) Metaphase • 4) Anaphase • 5) Telophase mitosis
Interphase • Divided into 3 Stages: • G1 Stage • Normal function performed • Cell growth • Organelles created • S Stage • Chromatin (DNA strands) duplicated • G2 Stage • Cell growth • Normal function performed
Prophase • 1st Mitosis Stage • Chromatin (DNA strands) coils into chromosomes • Nucleus dissolves • Spindle fibers form
Metaphase • 2nd stage of mitosis • Spindle fibers attach to centromere of chromosome • Spindle fibers pull chromosomes to cell equator
Anaphase • 3rd stage of mitosis • Spindle fibers pull ½ the chromatids to each end of the cell • Humans: 46 chromatids each way
Telophase • 4th stage of mitosis • Spindle fibers dissolve • Chromatids unwind into chromatin • Nucleus reforms • Cytokinesis: division of the cytoplasm • NOT APPART OF TELEPHASE
Animated Mitosis Clip Real Mitosis Video Clip
Name that Stage! Metaphase Hint: Chromosomes are aligned in middle of cell
Name that Stage! Telophase Hint: Cell plate is splitting the cell
Name that Stage! Interphase Hint: Two normal looking nuclei of two cells
Name that Stage! Prophase Hint: Chromosomes are forming and the nucleus is gone
Name that Stage! Anaphase Hint: Chromatids are being pulled apart
Prophase Metaphase Interphase Telophase Anaphase
Mitosis A Quick Overview
Aging • Normal process • Observable changes in the body’s structure & function • Decreases the body’s ability to maintain homeostasis • Cessation of mitosis • Cells only divide a certain number of times & then stop • May be programmed genetically • Telomeres: Pieces of DNA found at the tips of each chromosome. • Protect the chromosome from losing base pairs • Guard against chromosomes sticking to each other • Each time a cell divides its chromosomes’ telomeres shorten. • After many divisions important parts of the DNA sequence may erode causing aging and or the death of cells. • Glucose • Gets added to proteins inside & outside our cells creating links between cells • Contributes to loss of elasticity and stiffening of tissues. • Free radicals • Cause damage to our carbon based molecules • Enzymes produced by organelles in our cells are suppose to break them down • Eating foods high in antioxidants (Vit C, E, betacarotene, selenium, etc) help combat the oxidation
REview • In order, name the 5 stages of the cell cycle. • Pick a stage of the cell cycle. Name 2things that happen in this stage. • Review the picture slides. Identify the stages based on the picture. • The division of the cytoplasm is called _____. • Which cells divide by mitosis? • During which interphase stage is DNA created? • During which stage do spindle fibers form? • During which stage are chromosomes aligned in the middle? • During which stage are chromatids separated? • During which stage does the nucleus dissolve? • What are telomeres and what do they do?