Use the information in the next paragraph to answer the following two questions

Question

Use the information in the next paragraph to answer the following two questions below: Marine cone snails from the genus Conus are estimated to consist of up to 700 species. These predatory molluscs have devised an efficient venom apparatus that allows them to successfully capture polychaete worms, other molluscs, or in some cases fish as their primary food sources.... conotoxins from Australian species of Conus have the capacity to inhibit specifically the nicotinic acetylcholine receptors in higher animals. (B. G. Livett, K.R Gayler, and Z. Khalil. 2004. Drugs from the sea: Conopeptides as potential therapeutics Current Medicinal Chemistry 11:1715-23.) 82. This particular conotoxin inhibits acetylcholine receptors that promote the depolarization of skeletal muscle cells. These receptors are located A) on the presynaptic membrane of the neuromuscular junction B) on the postsynaptic membrane, on the muscle cel C) along the motor neuron axon D) on motor neuron dendrites 83. What is the adaptive value of this toxin? l) It would cause muscle spasms in the prey Il) It would result in paralysis of the skeletal muscle of the prey Il) It would stimulate digestive tract smooth muscle to cause nausea and vomiting in the prey A) only I B) only lI C) only il D) only I and II 84. Rods exposed to darkness will A) hyperpolarize due to the closing of sodium channels B) hyperpolarize due to the closing of potassium channels C) depolarize due to the opening of sodium channels D) depolarize due to the opening of potassium channels 85. In the light rhodopsin will be -. t transducin will be bound to , and the concentration of cyclic guanosine monophosphate (cGMP) in rod cells will be A) inactive, GDP, lower B) inactive, GTP: lower C) active, GTP, lower D) active; GDP: higher 86. A mouse carrying a homozygous mutation in the TRPV1 channel, which opens with hot temperature, is likely to be unresponsive to hot temperature as well as to A) hot chilli peppers B) firm touch C) cold temperature D) red ight 87, Transient receptor potential (TRP) channels can be gated by-_. A) voltage B) neurotransmitters C) temperature D) light 88. You learned in lecture and through an NPR radio clip that UC Berkeley scientist Diana Bautista's work supports the concept of a "labeled line" in sensory transduction. Which of the following results would best support the concept of a "labeled line"? A) the Sichuan pepper activates taste neurons in the tongue B) the 'buzz' from your cell phone activates vibration sensitive neurons in your tongue C) both vibration and the Sichuan pepper activate the same neurons and cause the perception of a "buzz D) the Sichuan pepper causes hyperpolarization of neurons in your tongue Page 12 of 22

Explanation / Answer

82). B. on the post synaptic membrane, on the muscle cell.

The skeletal muscles are innervated by the somatic nervous system and the neurotransmitter released is acetyl choline. Acetylcholine acts on nicotinic receptors of acetylcholine (post synaptic) and causes skeletal muscle contraction. Conotoxins inhibit this effect of acetylcholine.

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