Lecture 4

Question 1

G-protein coupled receptor

Answer 1

• Activates a second messenger pathway that carries out the response
• Ion transport or more complex
• Cascade of enzymatic reactions or 2nd messengers
• Fast or slow, generally short lived

Question 2

Receptor-enzyme complex

Answer 2

• Activates Tyrosine-kinase which phosphorylates designated proteins that lead to the cells response
• Often complex response, like cytoskeletal change
• Receptor is a kinase
• Phosphorylates itself
• Cascade of enzymatic reactions
• Can be slow, long lived

Question 3

Paracrine

Answer 3

localized, short range messenger, effecting neighboring cells only. Distributed by simple diffusion into the interstitial fluid. (Ex. Histamine; released to dilate blood vessels in area of invasion or injury)

Question 4

Autocrine

Answer 4

same as paracrine but acts only on the cell that releases it.