You discover a new species of poison-dart frog which secretes a neurotoxin in the skin mucous with LD50 of 0.5 mg/kg in humans. The toxin causes numbness, paralysis, arrhythmias, cardiac failure, and death. Based on the patch-clamp record of inward currents when the neurotoxin was applied to squid axon shown in Figure 2, suggest the mechanism of action of the neurotoxin. 500 PA 5 ms Figure 2 (Source: Google image)

First, we will build a model for the total amount of drugs in the gut. At time \(t = 0\), \(10mg\) of the drug is present in the gut. From the gut, it passes slowly into the blood. The passage of the drug to the blood has first-order kinetics; that is, every hour \(42\%\) of the drug remaining in the gut is passed from the gut into the blood. No more pills are taken, so no extra drug is added to the gut.   Let \(a_t\) be the sequence representing the amount of Adderall XR in the patient’s gut \(t\) hours after the pill was taken. Write down a recursion relation for \(a_t\).   Find an explicit formula for \(a_t\).   Calculate the time at which the amount of drug remaining in the gut drops to \(1\%\) of its starting value; that is, find \(t\) for which \[a_t = 0.01a_0\] Find \(\lim_{t\to\infty}a_t\), what does it represent?   Now let’s build a model for the amount of drug in the patient’s blood. Define another sequence \(b_t\) that represents the amount of Adderall XR in the patient’s…

i found this past paper but cant find the answers for my revision. please can you answer question 1e

1) Which statement about the electric organ is FALSE? A) the electric eel has postively charged cells on one of its body and negatively charged cells on the other B) the electric organ consists of a stack of cells with Na+ channels on one side C) an electric eel can maximize the shock delivered to a prey animal by contacting it with both ends of its body D) in the electric organ positive ions diffusing into the cells make the surrounding membrane positive 2) Which of the following sensory systems does NOT use hair cells with kinocilia and stereocilia that have ion channels at their bases? A) lateral line system B) vestibular apparatus C) hearing D) All of these sensory systems utilize hair cells with kinocilia and stereocilia.

Experimenters injected increasing amounts of bark scorpion venom into mouse neurons and measured the flow of sodium ions (current) across the cell membrane.  The scorpion toxin binds to the voltage-gated sodium channel Nav1.8.  What effect does the venom have on Nav1.8 in grasshopper mouse, that allows it to ignore scorpion bark stings?

Which treatment would eliminate the early inward current in a squid giant axon? O Applying a calcium channel blocker Removal of external potassium Removal of external sodium O Applying a potassium channel blocker

In paralytic shellfish poisoning, the dinoflagellates involved produce a type of neurotoxin.  What does the neurotoxin do to action potentials?