High School Biology : Nervous System
Study concepts, example questions & explanations for High School Biology
All High School Biology Resources
Example Questions
Example Question #1 : Understanding Neurotransmitters
Which of the following ions is required for vesicles containing neurotransmitters to be released into the synaptic cleft?
Vesicles containing neurotransmitters must bind to the membrane at the axon terminal in order to release their contents into the synapse. This binding is dependent upon an influx of calcium ions that occurs with an action potential. The other ions listed are important for other parts of the action potential, but it is calcium that is crucial for this particular step.
Example Question #5 : Understanding Neurotransmitters
Fill in the blanks with the best answers:
__________ gated potassium channels are the primary mediators of __________ of the neuronal membrane. They permit the postively charged potassium ions to flow out of the cell once the peak of the action potential has been reached.
Voltage . . . equilibration
Voltage . . . depolarization
Ligand . . . permeabilization
Ligand . . . repolarization
Voltage . . . repolarization
Voltage . . . repolarization
Voltage-gated potassium ion channels are responsible for bringing the membrane potential back to or below resting the potential. This is achieved when these channels open, which can only happen at very positive voltages (hence voltage-gated), and as the potassium ions rapidly leave the cell, the cell repolarizes to a negative potential.
Example Question #6 : Understanding Neurotransmitters
Which of the following receive messages from other neurons?
Dendrites
Nodes of Ranvier
Neurotransmitters
Synapses
Axons
Dendrites
The dendrites receive the messages sent from other neurons. Neurotransmitters are released into synaptic clefts between two neurons and bind receptors on the postsynaptic neuron's dendrites. Axons are nerve fibers that carry electrical impulses away from the cell body of a neuron. The nodes of Ranvier are unmyelinated spots on myelinated axons that facilitate conduction of a nerve impulse down an axon.
Example Question #7 : Understanding Neurotransmitters
Which of the following mechanisms would prolong the effects of the neurotransmitter acetylcholine?
Inhibiting acetylcholinesterase, an enzyme that degrades acetylcholine
More acetylcholine re-uptake receptors on the post-synaptic membrane
Adding acetylcholinesterase, an enzyme that degrades acetylcholine
More acetylcholine re-uptake receptors on the pre-synaptic membrane
More receptors on the post-synaptic membrane
Inhibiting acetylcholinesterase, an enzyme that degrades acetylcholine
The effect of acetylcholine is terminated by acetylcholinesterase breaking down acetylcholine. If acetylcholinesterase is inhibited, the degradation of acetylcholine would not occur, and the effects of acetylcholine will be prolonged.
Example Question #8 : Understanding Neurotransmitters
In the human brain, what is the primary inhibitory neurotransmitter?
Acetylcholine
Glutamate
Norepinephrine
GABA
Glycine
GABA
GABA is only found in the brain and has an inhibitory function. Although glycine is also inhibitory and found in the central nervous system, it's mainly concentrated in the spinal cord and brainstem. Glutamate and acetylcholine are also found in the central nervous system, but are excitatory. Norepinephrine is excitatory and associated with the adrenal glands, not the central nervous system.
All High School Biology Resources
