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14 Cards in this Set
- Front
- Back
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What morphological changes occur during apoptosis?
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1. cells shrink
2. chromatin condenses and fragments (DNA fragmentation) 3. cytoskeleton disassembles 4. nuclear envelope collapses 5. cell surface blebs 6. plasma membrane is chemically altered to promote phagocytosis - loss of phospholipid asymmetry: phosphatidylserine flips to the outer leaflet 7. loss of proton motive force in mitochondria |
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Apoptosis vs. necrosis
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Necrosis:
- result of acute injury - cells swell and burst - causes inflammatory response Apoptosis: - cells are degraded from inside out - do not damage other cells |
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What induces apoptosis or cell death?
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Absence or low amounts of survival factors.
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What assay detects apoptosis?
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TUNEL assay
The newly generated DNA ends that result from genomic cleavage can be detected in cells by modifying the ends of DNA with a fluorescent nucleotide. |
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What are caspases and what do they do?
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cysteine-aspartic proteases involved in apoptosis + inflammatory response
activation of caspases is the primary mechanism of destruction |
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How are initiator caspases activated?
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initiator procaspases are activated in response to a
signal through their caspase recruitment domain (CARD), and start the activation cascade |
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What do initiator caspases do?
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they propagate the activation cascade through executioner caspases
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What caspases are involved in inflammation?
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caspase 1, 2, and 4
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What are the two pathways for initiator caspases, and what are some example caspases in each?
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extrinsic pathway
- caspases 8, 10 intrinsic pathway - caspases 2, 9 |
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What are examples of executioner caspases?
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Caspases 3, 6, and 7
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The caspase casade in apoptosis is ____, ___, and ___. Describe the casade.
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destructive
self amplifying irreversible One molecule of initiator --> many executioner --> cleavage of cytosolic protein & nuclear lamina |
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What are the two pathways of apoptosis, and what triggers each?
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Intrinsic
- triggered by injury or stress - lack of oxygen, nutrients, or survival signals - DNA damage Extrinsic - Activation of Cell surface receptors (death receptors) |
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Describe the extrinsic pathway of apoptosis.
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- killer lymphocyte with Fas ligand binds
- activation of Fas death receptors - FADD adaptor protein binds to death receptor - procaspase 8, 10 binds to FADD adaptor --> Assembly of DISC --> activation and cleavage of procaspase 8, 10 --> activation of executioner caspases ---> apoptosis |
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Death domain receptors are homotrimers of ________.
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TNF (tumor necrosis factor) family
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