1.Based on the discussion about neurons in lecture, a. the nucleus and most of t
ID: 199107 • Letter: 1
Question
1.Based on the discussion about neurons in lecture, a. the nucleus and most of the organelles are contained in the cell body b. the dendrites are bushlike projections that bring information from other neurons or sensory cells to the cell body c. the axon carries information away from the cell body d. all of the above e. b and c, but not a 2. Based on the discussion in lecture, which of the following statements about the ion channels in the plasma membranes of neurons is FALSE? a. Some channels are gated, meaning that th ey open under some conditions but not others whereas other channels are always open. b·The channels are protein molecules and allow ions to move across the plasma membrane from regions of low concentration to regions of high concentration c. The channels are selective, in that they may allow only a single type of ion to pass through d. Some channels open or close in response to a change in the voltage across the plasma membrane 3. The potassium equilibrium potential is the point at which the movement of K ions into the neuron due to the negative electrical potential a. is balanced by the diffusion of K ions out of the neuron due to the concentration gradient. b. is equal to the rate at which K ions are moved out of the neuron by the sodium-potassium pumps c. both of the above d. none of the above 4. Voltage-gated sodium channels in the plasma membrane of a neuron a. are mostly open at normal membrane resting potentia b. enable Na ions to move out of the neuron along an electrochemical gradient when their activation gates are open c. are primarily responsible for generating and propagating action potentials d. all of the above e. b and c, but not a 5. Based on the discussion in lecture about the postsynaptic cell at a synapse between a motor neuron and a skeletal muscle cell, a. the plasma membrane of the postsynaptic cell contains receptors that bind acetylcholine b. activated receptors in the plasma membrane of the postsynaptic cell open chemically-gated sodium channels, which leads to depolarization c. both of the above d. none of the aboveExplanation / Answer
1.
All of the given statements are true. Hence, the answer is d. all of the above.
2.
b. the channels are protein molecules and allow ions to move across the plasma from regions of low concentration to regions of high concentration. The opposite also occurs, the channels allow the otherwise impermeable ions to move across the membrane.
3.
a. is balanced by the diffusion of K+ ions out of the neuron due to the concentration gradient. However, the electrical potential difference counterbalances diffusion due to the concentration difference is the equilibrium potential.
4.
a. are mostly open at normal membrane resting potential.
5.
c. Both the above. The membrane of the postsynaptic cell contains receptors that bind acetylcholine, and activated postsynaptic cell open chemically-gated sodium channels, which lead to depolarization.
6.
e. and b, but not c. Endorphin and glutamate are neurotransmitters, but not cAMP. cAMP is a second messenger.
7.
a. GABA is an excitatory neurotransmitter in the synapses between neurons in the CNS.
8.
d. all of the above
9.
e. a and b, but not c. Pressure waves in the cochlea cause the basilar membrane to flex, and ossicles in the fluid-filled inner ear amplify and transmit vibrations of the oval window.
10.
d. all of the above. When activated, the plasma membrane of the sensory cell is depolarized, the action potential is generated and propagated in the plasma membrane of the sensory cell, and the sensory cell releases a neurotransmitter.
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