ch18 Flashcards
apoptosis vs necrosis
-apoptotic cells have intact plasma membrane, condensed chromatin, & distorted/concentrated at margin of nucleus
-necrosis seems to have exploded
apoptosis significance
-gets rid of unwanted cells
-how animals shape through development
-metamorphosis
-what chemotherapy and radiation are based off of
-mostly for damaged cells beyond repair
visible hallmarks of apoptosis
- chromatin and cytoplasm condense & concentrate against nucleus margin
- nuclear fragmentation initiates cell fragmentation
- phagocytosis from other phagocytic cell
Initiator caspases
First responders to apoptotic signals
Executor caspases
Execute the hallmarks of apoptosis
Extrinsic pathway
FAS ligand/FAS receptor- mediated pathway triggered by events that occur outside of the cell
trigger a caspase cascade initiating apoptosis
Intrinsic pathway
trigged by intracellular events and controlled by the mitochondria
trigger a caspase cascade initiating apoptosis
regulation of onset of apoptosis-p53
-monitors DNA damage
-can trigger activation of genes that promote apoptosis or restrain cell growth
-eliminates the irreparably damaged
Initiator process
- Initiator caspase monomers are inactive and separate
- Signal binds monomers together into activated dimer
- Cross-cleavage within dimer
- Becomes mature active initiator caspase and goes to activate executioner
Executor process
- Inactive executioner caspase dimer
- Active initiator caspase activates dimer by cleavage
- Mature active executioner caspase promotes cleavage of cell proteins and starts apoptosis