Cell Death Flashcards
How do cells die? (3)
Necrosis
Apoptosis
Autophagy
When is apoptosis important?
Embryological development
Normal tissue homeostasis
Neoplastic disease
Apoptosis is used to remove
Unwanted cells in developing tissues
Extrinsic cell death pathways
Signals from external environment causes cells to apoptose
Intrinsic cell death pathways
Intracellular responses to cell damage causes cells to apoptose
Extrinsic pathway (3 parts)
external ligands bind to ‘death receptors’
receptors transduce death signal
activation of caspases
Intrinsic pathways (4 parts)
cell injury, radiation, toxins, free radicals
absence of growth factors
cytochrome c released by mitochondria
activation of caspases
key features of apoptosis, 7
activation of caspases cells shrink lose contact with other cells chromatin condensation membrane blebbing DNA fragmentation packaging of organelles
Apoptotic bodies contain:
intact mitochondria
lysozomes
ribosomes
Apoptotic bodies are phagocytosed by
neighbouring cells or macrophages
In apoptosis, cell contents not allowed to leak into extracellular space, therefore there is no
Inflammatory response
In cell viability test, trypan blue and propidium iodide will only enter
Non-viable, therefore permeable cell
Trypian blue stains cell ….. and the PI stains the nucleus ….
Blue
Red
TUNEL assay is method for detecting ….. by …..
DNA fragmentation
Labelling terminal end of nuclei acid
TUNEL assay relies on nicks in DNA which can be identified by an
enzyme
Apoptest uses flourescent marker attached to
annexin V
In apoptest, flourescent marker will attach to a specific … whch flips to outside during…
Phospholipid
Apoptosis
Autophagy is a form of …. and literally means…..
cell death
eating yourself