c. As a building block for making proteins
*d. To enable it to metabolize glucose
63. Dalton has been diagnosed with Korsakoff’s syndrome. What likely caused his disorder?
a. He is an alcoholic and has damaged his nervous system such that glucose cannot cross the blood-brain barrier.
b. He has been exposed to a virus that has now started killing neurons.
*c. He doesn’t have enough thiamine probably as a result of chronic alcoholism.
d. His glial cells are overactive and are damaging healthy neurons.
64. Korsakoff's syndrome ____.
*a. is marked by severe memory impairments
b. results from too much thiamine
c. results from lack of oxygen to the brain
d. is due to a breakdown of the blood-brain barrier
65. The membrane of a neuron is composed of ____ with ____ embedded in them.
a. carbohydrates; purines
*b. phospholipids; proteins
c. proteins; neurotransmitters
d. benzene molecules; carbohydrates
66. What term describes the difference in voltage that typically exists between the inside and the outside of a neuron?
a. Concentration gradient
b. Generator potential
*c. Resting potential
d. Shock gradient
67. In order to change the amount of polarization of a neuron, Professor Alley would need to change the difference in voltage between _____.
a. the dendrites and the axon hillock
b. the axon and the soma
c. inside the nucleus and outside the nucleus
*d. inside the cell and outside the cell
68. The resting potential is mainly the result of ____.
*a. negatively charged proteins inside the cell
b. positively charged proteins inside the cell
c. negatively charged proteins outside the cell
d. positively charged proteins outside the cell
69. Professor Durrant explained to his students that the resting potential of a neuron is the ______.
a. total amount of positive charge inside the neuron relative to the outside
*b. total amount of negative charge inside the neuron relative to the outside
c. total amount of sodium ions compared to potassium ions
d. the amount of positive charge in the dendrites compared to the axon
70. Pok is in the lab and is measuring the resting potential of neurons. Approximately what should she measure as the resting potential?
a. -65 millivolts
b. 0 millivolts
c. 70 millivolts
*d. -70 millivolts
71. When the neuronal membrane is at rest, the potassium channels ____.
a. permit potassium ions to pass quickly and easily
*b. permit potassium ions to pass slowly
c. prohibit any movement of potassium ions
d. help to open up the sodium channels
72. Jena is reviewing her notes on action potentials for a quiz. She makes an extra notation that before the action potential when the neuron is at rest, sodium channels _____.
a. are open and allow sodium ions to flow through easily
*b. are closed and don’t allow sodium to pass through.
c. are partially open, so sodium leaks through slowly
d. are partially open but at equilibrium, so the sodium doesn’t move
73. Professor Rhodus is lecturing about selective permeability of neurons. What would he tell the class?
a. All ions can only travel in one direction across the membrane.
b. All molecules must cross the membrane via a designated channel.
*c. Only certain molecules can cross the membrane freely.
d. Only sodium and potassium ions can cross the membrane.
74. When a neuron’s membrane is at rest, the concentration gradient tends to move sodium ____ the cell and the electrical gradient tends to move it ____ the cell.
*a. into; into
b. into; out of
c. out of; into
d. out of; out of
75. When a neuron’s membrane is at rest, the concentration gradient tends to move potassium ____ the cell and the electrical gradient tends to move it ____ the cell.
a. into; into
b. into; out of
*c. out of; into
d. out of; out of
76. Electrical gradients lead to the ____.
a. general movement of ions into the neuron
b. general movement of ions out of the neuron
c. movement of ions to areas having the same electrical charges
*d. movement of ions to areas having opposite electrical charges
77. Under which conditions would the sodium-potassium pump likely be far less effective in creating a concentration gradient?