Practise IB Biology HL C2.2 with membrane-potential traces and synapse data covering action potentials, neurotransmitters, saltatory conduction, summation and drugs.
130 questions in this syllabus scope, with question parts counted together.
117 papers analysed · Tagging incomplete
Young and old rabbits were tested in a classic reflex conditioning experiment. The ringing of a bell (conditioned stimulus) was followed after a delay of either 600 or 750 milliseconds (ms) by an eyeblink stimulus consisting of a mild puff of air to the cornea (unconditioned stimulus). Conditioned learning was measured by the percentage of rabbits that blinked their eyes with the ringing of the bell only. The graph shows the outcome after several trials.
The diagram shows a reflex arc.
On the diagram, label
On the reflex arc diagram, label a motor neuron.
On the reflex arc diagram, label a sensory neuron.
What occurs during the establishment of a resting membrane potential of a neuron?
Both sodium and potassium ions are pumped outside the neuron.
Sodium ions are pumped out while potassium ions are pumped into the neuron.
Both sodium and potassium ions are at rest inside the membrane of the neuron.
Sodium ions leave by diffusion and potassium ions enter the neuron by active transport.
Where could an action potential occur in a motor neuron?
Anywhere on the cell membrane
Dendrites only
Cell body only
Axon only
The conduction velocity of electrical impulses was measured in different myelinated nerve fibres.
Which hypothesis would explain the higher conduction velocity of nerve fibre R, compared to nerve fibres P and Q ?
It is the longest.
It has the thinnest myelin sheath.
It has the largest diameter.
It has the greatest number of mitochondria.
The diagram shows the synaptic transmission of nerve impulses by the neurotransmitter acetylcholine.
What is the fate of acetylcholine immediately after binding to the receptor?
It is pumped into the postsynaptic neuron.
It diffuses into the presynaptic neuron.
It is broken down in the synaptic cleft.
It binds to another receptor in the postsynaptic neuron.
What occurs during the transmission of an impulse at a synapse?
I. Acetylcholine is released into the synaptic cleft by exocytosis when calcium ions enter the presynaptic neuron.
II. Acetylcholine diffuses across the synaptic cleft and binds to receptors on the postsynaptic membrane.
III. Acetylcholine is broken down by cholinesterase and resorbed into the presynaptic neuron once an impulse has been initiated on the postsynaptic membrane.
I and II only
II and III only
I and III only
I, II and III
Atropine drops are used by opticians to dilate the pupil, so that a thorough examination of the retina can be performed. Atropine binds to acetylcholine receptors in synapses.
What is the effect of atropine binding in synapses?
Inhibits the binding of acetylcholine at the presynaptic membrane
Inhibits the release of acetylcholine from the presynaptic neuron
Prevents binding of acetylcholine at the postsynaptic membrane
Prevents transport of acetylcholine through the postsynaptic membrane
The graph below shows an action potential.
Where on the graph do the sodium channels open?
At 1
Between 1 and 2
At 2
Between 2 and 3
The image shows human red blood cells.
Explain the propagation of nerve impulses along the membrane of a neuron.
The graph shows an action potential.
What is the change in membrane potential from resting potential to complete depolarization?
-70 mV
15 mV
40 mV
110 mV
The image shows a neuron.
What is the function of X ?
Increases the speed of transmission along the axon
Increases the rate of exchange of sodium and potassium ions
Holds bundles of neurons together to form a nerve
Determines the direction of the action potential
Diagrams X and Y show the possible action on synaptic transmission of two exogenous chemicals.
Key:
- neurotransmitter
- neonicotinoid or cocaine
Cocaine and neonicotinoids have different modes of action. Which statement identifies the correct mode of action of one of these chemicals?
Y shows cocaine because it prevents binding of the neurotransmitter to the postsynaptic membrane.
X shows neonicotinoid because it is taken up by the presynaptic terminal.
Y shows neonicotinoid because it binds to the neurotransmitter.
X shows cocaine because the neurotransmitter cannot be taken up by the presynaptic terminal.
No public sample questions are available for this syllabus point yet.
An organism's diminished response to a repeated stimulus is referred to as habituation. The diagrams show the experiments performed on habituation to a stimulus in a sea slug (Aplysia californica). The sea slug is a mollusc that has an external gill for gas exchange. If the siphon of the sea slug is stimulated mechanically, it withdraws the gill in a simple reflex action.
Control
Control
With repeated stimulus (habituation), the sea slug no longer withdraws the gill.
Habituated
With reference to the withdrawal of the siphon in Aplysia californica, explain the concept of summation.
No public sample questions are available for this syllabus point yet.
Compare and contrast the scan results for the healthy controls with the scans for the stroke survivors.
