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14 Cards in this Set
- Front
- Back
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What are the features of apoptosis? |
Changes in nuclear morphology Chromatin condensation (pyknosis) Chromatin fragmentation (karyorrhexis) Cell shrinkage Cytoplasm collapse Plasma membrane blebbing Lack of inflammatory response |
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What is autophagy? |
Self-cannibalization process involving lysosomal degradation pathways
Early organelle degradation |
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Why undergo autophagy? |
Survival strategy
Produces catabolic ATP for protein and organelle turnover in times of nutrient-replete conditions |
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Comparison of cell death by apoptosis and necrosis Induction, extent, biochemical events, cell membrane integrity |
Induction - A: physiological/pathological, N: Pathological Extent - A: Single cells, N: Cell groups Events - A: Energy-dependent fragmentation of DNA by endogenous endonucleases, lysosomes intact, N - energy failure, lysosomes leak Membrane integrity - A: maintained, N- lost |
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Comparison of cell death by apoptosis and necrosi Morphology, Inflammatory response, fate of dead cells |
Morphology - A: shrinkage, frag., apoptotic bodies with dense chromatin, N - swelling and lysis N - inflammatory response Fate of dead cells - A: ingested by neighbouring cells, N - ingested by neutrophils |
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What are the four phases to apoptosis? |
Initiation (trigger)
Signal integration (decision) Execution (demolition) Clearance (disposal) |
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What are Intrinsic Triggers of apoptosis? |
DNA Damage Protein misfolding Oxidative damage Lack of survival factors Adhesion to extracellular matrix Cell-Cell interactions |
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How can signal integration cause apoptosis? |
Overexpression of Pro-apoptotic proteins: Underexpression of Anti-apoptotic proteins: |
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What are capases? |
Cysteine Aspartyl-specific Proteases Disassembly of cellular structures (nuclear membrane, nuclear lamina, cytoskeleton, intra- and inter-cellular communication) |
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How is apoptosis initiated? |
Polarised cells Signals No structural changes |
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How is apoptosis executed? |
Protease enzymes (Caspases) cause severe structural changes Cell shrinkage, Cytoskeleton, lamina degradation, affects polarisation, chromatin condensation |
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Degradation phase of apoptosis? |
The cell splits up into apoptotic bodies which contain viable Mi and other intact organelles |
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Phagocytic phase of apoptosis? |
Apoptotic fragments phagocytosed by adjacent cells where they are destroyed Some - degenerate extracellularl Some - ingested by phagocytic cells |
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How is apoptosis detected? |
Morphology Mitochondrial membrane potential- dyes Antibody markers - annexin normally on inner Mi membrane, flips |
