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Cell Growth and Division
Biology
Ms. Lew
Vocabulary (p. 90-91)
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Cell Cycle
Chromatin
Chromosome
DNA overload
Interphase
Sister Chromatid
Spindle Fiber
What is the cell cycle?
• During the cell cycle, a “parent” cell grows
and divides to form 2 “daughter” cells.
• The cycle has three main stages
–Interphase
–Mitosis
–Cytokinesis
Remember the two reasons why
cells divide rather than continue
to grow larger:
DNA Overload
1. __________________________________
Exchanging Materials
2. _________________________________
DNA overload is when the DNA has
too many tasks to do (such as
making proteins) and not enough
DNA to get the job done efficiently.
The Cell Cycle
• Animation
G1
M
G2
S
Interphase – G1 , S & G2
• During Interphase cells:
– G1 phase: Grow to mature size
• Mitochondria and chloroplasts are duplicated
– S phase: Replicate (copy) DNA
– G2 phase: Prepare for cell division
• Cell grows
• Most of a cells life is spent in Interphase.
Chromosomes
• Are made of DNA, histones, chromatin
• Each chromosome consists of sister
chromatids attached at a centromere
• Each sister chromatid is an exact copy
Mitosis – M phase
• The cells nucleus divides into two nuclei
• There are four phases
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Prophase
Metaphase
Anaphase
Telophase
P M A T
Animal Cell Mitosis- Video
Prophase
• 1st stage of Mitosis
• Chromatin condenses into chromosomes
• Centrioles separate and a spindle fiber
begins to form.
• Nuclear membrane breaks down
Prophase
Metaphase
• 2nd Phase of Mitosis
• Chromosomes line up in the middle of the
cell.
• Each chromosome is connected to a
spindle fiber.
Metaphase
Anaphase
• 3rd Phase of Mitosis
• The sister chromatids separate at the
centromere and move to opposite ends of
the cell.
Anaphase
Telophase
• 4th Stage of Mitosis
• Chromosomes gather at opposite ends of
the cells and lose their shapes (return to
chromatin form)
• Two new nuclear membranes form, one
for each cell.
Telophase
Cytokinesis
• The cytoplasm pinches in half.
• Each daughter cell has an identical set of
duplicate chromosomes
Cytokinesis
Overview sim
• http://www.sumanasinc.com/webcontent/a
nimations/content/mitosis.html
Plant cell mitosis
• https://www.youtube.com/watch?v=aDAw2
Zg4IgE
And Another one…
• https://www.youtube.com/watch?v=KzBoI
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