View
214
Download
0
Category
Tags:
Preview:
Citation preview
MitosisCh. 9.1-9.3
Objectives
1. Describe how cell reproduction contributes to repair and growth
2. Structure of a chromosome
3. Explain cell cycle
4. Understand mitosis and cytokinesis
5. Basics of cancer
Two Functions of Cells1. Repair
2. 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
An idea of where we’re at
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)
Cell Cycle Video Clip
Check Your Neighbor
• Quiz your neighbor on the cell cycle….
Mitosis• Mitosis:
– Non-sexual means of cellular reproduction
• Four Stages:1. Prophase2. Metaphase3. Anaphase4. 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 JiveProphase Metaphase
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
How a tumor is formed
Proto-oncogenes encourage cell division
Recommended