Bio 152 Final Exam Review (With A+ Graded solutions)

For a neuron with an initial membrane potential at -70 mV, an increase in the movement of potassium ions out of that neuron's cytoplasm would result in the _____. correct answers hyperpolarization of the neuron The operation of the sodium-potassium "pump" moves _____. correct answers sodium ions out of the cell and potassium ions into the cell ATP hydrolysis directly powers the movement of _____. correct answers Na+ out of cells The "threshold" potential of a membrane is the _____. correct answers minimum depolarization needed to operate the voltage-gated sodium and voltage-gated potassium channels The membrane's permeability to sodium ions is at its maximum at _____. correct answers -50mV The cell is not hyperpolarized; however, repolarization is in progress, as the sodium channels are closing or closed, and many potassium channels have opened at _____. correct answers the maximum mV of graph If you experimentally increase the concentration of K+ inside a cell while maintaining other ion concentrations as they were, what would happen to the cell's membrane potential? correct answers The membrane potential would become less negative. If the activity of the sodium-potassium pump was completely stopped, what would happen to the neuron's membrane potential? correct answers slow decrease of resting potential Tetrodotoxin blocks voltage-gated sodium channels and ouabain blocks sodiumpotassium pumps. If you added both tetrodotoxin and ouabain to a solution containing neural tissue, what responses would you expect? correct answers immediate loss of action potential with gradual loss of resting potential Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In freshwater, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon's moves between freshwater and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following? A) evolution B) trade-off C) acclimatization D) adaptation correct answers C) acclimatization