The Cell Cycle, Programmed Cell Death and Cell Division

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Lecture 17

• The Cell Cycle, Programmed Cell Death and Cell
  Division

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The phases of cell cycle
S phase DNA duplication M phase DNA segregation
Metaphase, anaphase
Gap phases
Interphase G1, S and G2
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G0
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The morphology of budding yeast cells arrested by
a cdc mutation
The cell cycles of fission and budding yeasts
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(No Transcript)
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Analysis of DNA content with a flow cytometer
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Two key components of the cell cycle control
system
The core of the cell-cycle control system
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How DNA damage arrests the cell cycle in G1
Evidence from cell-fusion experiments for a
replication block
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An overview of the cell-cycle control system
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Apoptosis in development
Cell death
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The caspase cascade
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Induction of apoptosis by either extracellular or
intracellular stimuli
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A model of how mitogens stimulate cell division
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The function of cell death in matching the number
of developing nerve cells to the number of target
cells they contact
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The effects of a myostatin mutation on muscle size
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The M-phase of the cell cycle
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Two cytoskeletal machines that operate at M phase
Microtubule motors
Actin-based motors
M phase prophase, prometaphase, metaphase,
anaphase, telophase cytokinesis
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The three classes of microtubules of the fully
formed mitotic spindle
Motor proteins operate at or near the ends
orienting
shape
metaphase
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The major forces that separate daughter
chromosomes at anaphase in mammalian cells
Motors at the poles
Motor proteins at the kinetochore
Shortening mainly at their attachment, and, to a
lesser extent at the two spindle poles
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The contractile ring
Microtubules stabilize the ring
actin
myosin II
High dynamic actin filaments
The cleavage furrow
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The midbody tether between the two daughter
cells and contains the remains of the central
spindle--two sets of antiparallel overlap
microtubules tightly packet together
Interesting behavior of mother centrioles in
some cells Some of the components of
the residual midbody often remain on the inside
of the plasma membrane of each cell- marker on
the cortex to orient the spindle in the
subsequent cell division
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The special features of cytokinesis in a higher
plant cell
Phragmoplast remaining overlap MT
A new cell wall (cell plate) is built with
vesicles filled with cell-wall material plasma
membrane and the membrane surrounding the new
cell wall fuse
Preprophase band decides division plane and forms
before M phase
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• Summary
• Cell cycle, core cell-cycle control system
• Programmed cell death, caspases
• Cell cycle and cell death are regulated
• Cell division, mitosis, cytokinesis
• Mitotic spindle, contractile ring