Lecture 5

Question 1

What are the three types of local cell communication?

Answer 1

Gap junction, contact dependent signals autocrine/paracrine

Question 2

What are the two types of long-distance communication?

Answer 2

Neuronal and endocrine
Endocrine is from glands releasing into the bloodstream
Neuronal can be neurotransmitters (short distances) neuromodulators, or neurohormones (release into the blood)

Question 3

Compare/contrast the different receptor locations

Answer 3

Membrane: fast reactions, lipophobic, triggers series of intercellular reactions
Intracellular: slower reactions, lipophilic signals, affects gene activity

Question 4

What are the 4 different type of membrane receptors?

Answer 4

receptor-channels, receptor-enzymes, GPCR, integrin receptors

Question 5

Describe an example of a receptor enzyme

Answer 5

Tyrosine-kinase receptor: receptor binds signal, activates tyrosine kinase, which phosphorylates a tyrosine amino acid

Question 6

Describe GPCR and phospholipase C

Answer 6

molecule binds to GPCR, activates phospholipase C. converts a phospholipid in to IP3 (inositol trisphosphate) and DAG (diacylglycerol). IP3 releases Ca from organelles (ER) while DAG is converted into activates protein kinase C

Question 7

Describe GPCR and adenylyl cyclase

Answer 7

molecule binds to GPCR, activates adenylyl cyclase, converts ATP to cAMP which activates protein kinase A

Question 8

What are the two functions of GPCR

Answer 8

modulate enzyme activity, alter ion channel gating

Question 9

How can a GPCR affect ion channel?

Answer 9

G protein has 3 subunits, one subunit binds to channel, much like ligand-gated