TEST 2 Flashcards
What is an Ion Channel Receptor?
a membrane protein that acts as a receptor and an ion channel.
What is a Receptor Linked G-Protein?
membrane receptor whose effects are mediated by G proteins.
Binding of signalling molecule to receptor=confirmational change
Dissociation of GDP to GTP
Why is AMP called a second messenger?
it activates Protein Kinase A.
PKA phosphorylates other proteins.
Protein Kinase A has 2 regulatory subunits and 2 catalytic subunits.
Possible since each cell type has its own target protein
What are the advantages of AMP?
1) signal amplification: each step is catalytic. Receptor can activate many molecules.
2)Multi-step Cascade: provides felxibility. small mistakes arent lethal. each component has separate target to control.
Catalytic Receptor?
receptor protein functions as enzyme to transmit signal.
What is the different between apoptosis and necrosis?
Apoptosis: controlled and programmed cell death.
Eg: removal of webbing in embryos.
Necrosis: swelling and rupturing of injured cells.
What are the steps of apoptosis?
1) DNA Segregates, cytoplasm is decreased
2)cells produce Blebs
3)nucleus and organelles begin to Fragment
4) cell is Dismantled and removed by macrophages.
how do cells enter apoptosis?
1) Extrinsic: binding of death signalling receptor
2) Intrinsic: change inside cell trigger response
death receptor pathways?
caspases are produced (inactive form called procaspase). when activated, it cleaves other proteins
mitochondrial pathway to cell death?
mitochondria is involved when there is an absence of the death signal. usually when cell becomes damaged.
how to detect apoptosis?
look for things such as caspases, dna fragmentation, cell membrane changes, damage.
detecting DNA fragmentation in populations?
DNA fragments into 180bp long
detecting DNA fragmentation in individual cells?
labelling of DNA strands
