Previously

1
Previously
Hypotheses to explain cell life span Free
radical theory.. DNA damage DNA
replication problems (WRN). DNA damage
Telomere clock .. Length and .. DNA
damage Austriaco and Guarente paper Manipulate
the length of yeast telomeres What was the
effect on yeast lifespan
2
Organism requires cell proliferation and cell
death

• Why/ When would an organism need cell
  proliferation?
• Why/When would an organism need cell death?

3
Have discussed cell growth whats cell death

• Programmed cell death apoptosis
• vs
• Necrosis
• Compare and contrast

4
Apoptosis The movie

• CBI 17.1

5
Vesicles do not travel between cells Cell
fragments bleb and are engulfed by Other cells.
6
How does this all happen?

• Lack of survival factors
• Lack of growth factors to bind with growth factor
  receptors)
• Presence of Death activators
• Receive death signals to bind with death
  receptors (TNF, Fas ligand)
• Internal signal due to damage (p53)
• Results in activation of Caspase cascade

7
Caspase cascade the animation

• Apoptosis animation

Forming the apoptosome cytochrome
c Apaf-1 Caspase 9 ATP
8
Families of proteins are involved

• Bcl-2, Bcl-XL Anti-apoptotic
• Bad apoptosis promoter
• (inhibits a death inhibitor)
• Bax, Bak stimulate release of cyt. c
• IAP family inhibitors of apoptosis
• (bind procaspases block activation,
• binds caspases and inhibits activity)

9
Its a balancing act

• Must have correct amount of each, at the
  appropriate time

Cell death
Proliferation
Cell death
Proliferation
10
What remains

• There is lab this week (30min then time to work
  on presentation)
• Oral presentations Thurs and Tues
• You have the prefinal questionswork on them!!!
• Final exam available on Monday 5/2
• 2 parts I. Cumulative, from prefinal questions
• II. Third review Werners/Cellcycle

BOTH parts of FINAL due MONDAY May 9th BEFORE 9am