Download CELL CYCLE

CELL CYCLE
The events in the life of a cell
What do cells do ???
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Interphase
• Interphase is the time between cell
divisions where the cell grows to full size,
duplicates its DNA and rests
Inter means between
Interstate highway = BETWEEN States
Interphase
• Interphase is broken into three
different sub-phases
• G1,
G0, (part of G1)
• S
• and G2
Cell Cycle Diagram
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G1 Phase - Growth
Occurs just after cell division
• Cell must re-grow to normal size
• Proteins are made
G0 Phase – the Resting Phase
• Cell is “normal” during this phase
• Cell undergoes normal cell
functions while resting
• A cell that skips this phase can
become cancerous, growing
uncontrollably
Check points
• Places where cell checks itself for damage
before proceeding
• Cancer bypasses check points
S Phase - Synthesis
• DNA is synthesized or copied in
preparation for cell division
Point of no Return
Once a cell enters the S phase it is
committed to go through cell
division
(point of no return)
G2 Phase - Growth
• Cell grows larger in preparation
for cell division (like a bear
hibernating)
Cell Division
• The way a cell reproduces
• 2 steps:
1) Mitosis (M)
2) Cytokinesis (C)
M Phase - Mitosis
• Division of cell Nucleus
• DNA forms into chromosomes
• Chromosomes separate with identical
pairs moving to opposite sides of the cell
• New nuclear membrane forms around
each set of chromosomes
Mitosis
Chromo/somes = colored / bodies
Only appear during Mitosis
Chromosomes – made of DNA
1) Prophase
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Cell is beginning mitosis
DNA coils up forming chromosomes
Spindle fibers form
Nuclear membrane dissolves
Chromosomes
Centrioles appear
Centrioles
Spindle fibers
2) Metaphase
• Chromosomes line up along center
• Centrioles migrate to poles
• Spindle fibers attach to chromatids at
centromere
Chromosomes line up
Spindle fibers
centrioles
3) Anaphase
• Spindle fibers pull duplicate chromatids apart
• Chromatids migrate to opposite poles
Spindle fibers
Chromatids
4) Telophase
• Chromotids gather together on separate sides
• Membrane forms around chromatids making 2
separate nuclei
• Chromatids unwind
• Cell membrane begins to pinch together
Chromatids
Cleavage furrow
Nuclear membrane
C Phase – Cytokinesis
• Division of the cytoplasm and organelles
between cells
• Membrane closes off each cell
• 2 new daughter cells form, each an identical
copy of the original parent cell. (but smaller)
Daughter cells
Nucleus
DNA
cytoplasm
membrane
In plants, a cell plate forms to make
a new cell wall
Interphase (again)
• Each daughter cell enters
Interphase, so it can regrow, rest
and be a normal cell
Cell cycle humorous animation
• http://www.youtube.com/watch?v=qmTEid
drGOM
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animati
on__how_the_cell_cycle_works.html
Cell cycle animation