1. BIO HELP PLS!!!! a. Numerous interesting drugs and toxins act on channels and
ID: 34764 • Letter: 1
Question
1. BIO HELP PLS!!!!
a. Numerous interesting drugs and toxins act on channels and transporters. One such drug is scopolamine, which is used to treat vertigo, motion sickness, and smooth muscle spasms. Scopolamine was first isolated from Jimson Weed, which produces a beautiful white flower also called Sacred Datura and it was used by the native americans for religious purposes because it can produce hallucinations and time distortions. Imagine you are the first to purify scopolamine and are trying to determine how it works. You find that you incubate isolated muscle cells with scopolamine, subsequent addition of acetylcholine no longer causes membrane deporalization and cell contraction as does in absence of scopolamine.
Which of the following statements best explains how scopolamine might exert its effects? 3 pts
A. it binds to acetylcholine-gated Na+ channels and inhibits its opening. B. It inhibits opening of the Ca2+ channel in the sarcoplasmic reticulum C. It inhibits transporters that import Na+ during an action potential
D. It inhibits voltae gated K+ channels during an action potential.
b. Scorpion ? toxin, a component of the scorpion venom, dramatically prolongs the change in membrane potential during the firing of a nerve impulse as shown in figure below:
Which of the following hypotheses best explains how ? toxin exerts its effects? 3 pts
A. it accelerates the opening of voltage gated K+ channels B. It opens the voltage gated Na+ channel at a lower voltage C. It promotes the opening of a ligand gated Na+ channel
D. It slows the inactivation of the voltage gated Na+ channel
c. Extracts from the African plant stropthantus gratus were once used to make poison arrowheads for hunting. The active compound in the extract is extremely toxic.; when concentrated and placed on an arrowhead, it can kill a hippopotamus. Imagine that you treat cells with the compound and observe that they begin to swell and eventually burst. Which of the following actions would best explain the effects of the toxic compound? 3 pts
A. Closing of K+leak channels
B. Closing of na+ channels
C. Inhibition of glucose transporters D. Inhibition of the N+K+ pump.
Explanation / Answer
1.B. It inhibits opening of the Ca2+ channel in the sarcoplasmic reticulum.
b. B.It opens the voltage gated Na+ channel at a lower voltage.
c. D. Inhibition of the N+K+ pump
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