cell signaling and receptors

Question 1

4 different basic categories of chemical messengers

Answer 1

-hormones: secreted into circulating blood. long range communication short and long term effects.

-neurotransmitters: fast chemical transmission at neuronal synapses

-growth factors: long term control of cell growth and differentiation

-paracrine agents: local controls of cell behaviour in the immediate environment

there is substantial overlap

Question 2

4 types of receptor receptor

Answer 2

-ligand gated ion channels (MS)

-G protein coupled receptors (sec-min)

-catalytic receptors (min-hr)

-nuclear receptors (hr- day)

Question 3

G protein coupled receptors (sec-min)

Answer 3

-the protein is activated (eg. by a hormone) this causes communication with a separate effector protein that produce a response.

-three stage system offers a variety in messengers and recognised and a variety of cellular responses

Question 4

catalytic receptors

Answer 4

-receptor has intrinsic enzyme activity which is activated by a hormone binding

eg. tryosine Kinase

Question 5

nuclear receptors

Answer 5

Nuclear receptors mediate slow, long-term responses by acting as transcription factors that regulate gene expression in response to lipophilic (ready diffuse across membrane) ligands. receptors get activated and bind to DNA to promote transcription.

Question 6

affinity

Answer 6

the ability of a drug to bind to its receptor

Question 7

efficacy

Answer 7

the ability of a drug, one bound, to activate the receptor by a conformational change

antagonists don’t have this