lecture 13: cell signaling examples

Question 1

botulism

Answer 1

• muscle paralyzing disease
• caused by clostridium botulinum bacteria
• toxins secreted by bacteria disrupt signaling at neuron-muscular junction
• bacteria lives well without oxygen, can breed in canning

Question 2

correctly functioning pathway of muscle

Answer 2

neuron exocytoses signaling molecule to initiate signaling cascade in muscle cells that cause contraction

Question 3

disrupted pathway of muscle

Answer 3

toxins secreted by bacteria chop up proteins that mediate exocytosis in neurons; if neurons unable to exocytose ligand, muscles have no signal to respond to (cannot contract, paralysis)

Question 4

caffeine

Answer 4

• binds to an adenosine receptor to promote dopamine release at synapse of neurons
• is an inhibitor / antagonist

Question 5

cholera

Answer 5

• acute diarrheal disease
• infection of small intestine caused by bacteria vibrio cholerae - sticks to epithelial cells of small intestine
• comes from contaminated water

Question 6

pathway of cholera

Answer 6

1. bacteria releases toxin
2. toxin binds to GPCR
3. g protein is activated causing overproduction of cAMP
4. cAMP triggers CFTR channels to stay open (allows Na and Cl ioins to leave cell and go into intestine)
5. Cl and Na leave cell
6. osmosis
7. symptoms