Exam 2 - Name ClassTime Second Exam(Color BIO 365R Spring...

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Name__________________________ Class Time______________________ Second Exam (Color)- BIO 365R Spring Semester 2010 There are 60 true-false and multiple choice questions, each worth 1.43 points Question 1.  The increase in intracellular Ca ++  that causes contractions in skeletal muscle comes  from: a. The opening of voltage-sensitive Ca ++  channels in the sarcoplasmic reticulum. b. The opening of ryanodine receptors in the membrane of the T tubules. c. The opening of dihydropyridine receptors in the membrane of the T tubules, which  are mechanically coupled to ryanodine receptors in the sarcoplasmic reticulum. d. The release of Ca ++  from troponin, a Ca ++  storage molecule. Questions 2-5 .   The records on the left are intracellular recordings  from   ventricular cardiac muscle   fibers. The pacemaker was stopped  (don’t worry about how that was done) and action potentials were  evoked by delivering brief electric pulses to the fiber.  The investigator  then performed a number of manipulations on the solutions bathing the  heart.  In one manipulation, drug X, which blocks the Ih current, was  added to the bathing solution.  In another manipulation, TTX was added  to the Ringer solution (no cesium was present).   In a third, a small  amount of tetraethylamonium (TEA) was added (no TTX or cesium  was in the bathing solution).  In the fourth manipulation, cadmium, a  calcium channel blocker, was added to the bath (no TTX or cesium was  in the bathing solution). Mark on your Scantron which of the four  records shown above, A, B, C or D, would have been obtained from the  manipulations described above 2)  ___A___was the record obtained when drug X was added to the  solution.  3)  __D____was the record obtained when TTX was added to the solution. 4)  ___B___was the record obtained when TEA was added to the solution. 5 ) ___C___was the record obtained when cadmium was added to the solution. Question 6.  Adrenalin modulates heart-rate through one of the following mechanisms: a. Adrenalin binds to an ionotropic receptor, which causes the channel to open and  Na+ to  flow in and depolarize the cell. b. Adrenalin binds to a metabotropic receptor, which activates a G-protein mediated  1
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Name__________________________ Class Time______________________            chemical cascade resulting in Ca     ++      influx and thus faster contraction.     c. Adrenalin  binds to an ionotropic receptor, which causes the channel to open and  K+ to  flow out and hyperpolarize the cell. d.
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This note was uploaded on 11/11/2010 for the course BIO 365R taught by Professor Draper during the Fall '08 term at University of Texas.

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Exam 2 - Name ClassTime Second Exam(Color BIO 365R Spring...

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