Mitosis Ch. 9.1-9.3
Objectives • Describe how cell reproduction contributes to repair and growth • Structure of a chromosome • Explain cell cycle • Understand mitosis and cytokinesis • Basics of cancer
Two Functions of Cells • Repair • Growth • The outer layer of skin on your arm consists of dead cell. • Constantly replacing each other! • Cells also key in reproduction . . . more on that later
The DNA • Genetic material located in nucleus of cell • Most of the time it exists as chromatin • Chromatin: • Uncoiled DNA, not visible
ChromosomesHome of the DNA • Cell prepares to divide • Chromatin fibers condense and become… • Chromosomes: • Condensed, visible threads of genetic material • Yarn example • Humans have 46 chromosomes
ChromosomesHome of the DNA • Right before division, the cell duplicates all of it’s chromosomes • Sister Chromatids: • Identical, joined copies of chromosomes • Centromere: • Joining region of chromatids
Check Your Neighbor • Quiz your neighbor on the terms we just learned.
The Cell Cycle Let's Look at 3 examples of cell division (9.1 activity)
The Cell Cycle • All cells divide at different rates • Interphase: • 90% of cycle • Three stages during interphase: • G1 • Synthesis • G2 • Miotic Stage (10%)
Cell CycleStages of Interphase • G1: • Cell grows • Synthesis: • DNA duplicates • G2: • Cell prepares to divide • Cell Cycle Animation and Different Types of Cells That Divide (9.2)
Check Your Neighbor • Quiz your neighbor on the cell cycle….
Mitosis • Mitosis: • Non-sexual means of cellular reproduction • Four Stages: • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis • Let’s use pipe cleaners to demonstrate the stages of mitosis. Draw them out after you make them.
MitosisProphase • Nuclear envelope dissolves • Spindle forms • Chromosomes visible
MitosisMetaphase • Chromosomes line up along equator • Spindles attach
MitosisAnaphase • Chromatids separate • Pulled towards opposite ends of cell by spindles
MitosisTelophase • Chromatids uncoil • Nuclear envelope re-forms
Cytokenesis • Division of cytoplasm • Two identical daughter cells • Mitosis: Let's watch the real thing!
Hand Jive Metaphase Prophase Anaphase Telophase
Mitosis Quiz • When I pause the movie, you tell me what stage of Mitosis we are in.
Cancer • Family or friends with cancer? • Cancer: • Uncontrollable cell division • Faulty checkpoints • Out of control cell reproduction produces tumors • Benign tumor: • Abnormal mass of normal cells • Malignant tumor: • Mass of cancer cells • Metastasis: • Spreading of cancer cells Activity 9.4 More cancer animation