| Date | May 2022 | Marks available | 2 | Reference code | 22M.2.SL.TZ1.5 |
| Level | Standard level | Paper | Paper 2 | Time zone | Time zone 1 |
| Command term | Describe | Question number | 5 | Adapted from | N/A |
Question
The graph shows the change in the membrane potential of an axon during an action potential.
State the approximate value of the membrane potential at X.
Y is the threshold potential. State what happens when the threshold potential is reached.
Describe the movements in ions that occur during time t.
Explain how a nerve impulse is passed on to other neurons.
Markscheme
0 mV; (accept answers in the range of – 10 mV to +10 mV) (Units required)
sodium channels (start to) open
OR
depolarization/axon begins to depolarize
OR
action potential occurs;
Reject pumping of ions.
Na+/sodium ions diffuse into the axon (in the first part/half of t);
K+ /potassium ions diffuse out of the axon (in the second half/part of t)
Do not accept the name of the element without indication that it is an ion.
- impulses pass to another neuron at a synapse/across synaptic gap/cleft;
- (depolarization causes) Ca2+/calcium ions to diffuse into the (presynaptic) neuron/axon;
- depolarization (of presynaptic neuron) causes release of a neurotransmitter
OR
neurotransmitters diffuse across the synapse; - (neurotransmitters) bind to receptors on postsynaptic neuron/membrane;
- (if the threshold potential is reached) an action potential occurs/sodium gates open (in the postsynaptic neuron);
Examiners report
There were some truly brilliant answers to Question 5. However, the weakest answers in the examination were also found here. Of the questions, these were the most commonly left blank.
Candidates were often unable to approximate X. Missing units resulted in no marks awarded.
Fundamental terms such as action potential or depolarization were not used in Q5(b) and (c). Some candidates failed to distinguish between elements and ions.
Some candidates talked about ion movement but with no reference to a specific ion; some described the Na+/K+ pump here and received no marks.
Use of term "synapse" was often missing; involvement of the brain was sometimes built into the passage of a nerve impulse to another neuron.
Syllabus sections
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17N.1.SL.TZ0.28:
Which structure in the motor neuron is required for saltatory conduction?
[Source: https://commons.wikimedia.org/wiki/File:Anatomy_and_physiology_of_animals_Motor_neuron.jpg]
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22M.2.SL.TZ1.5a:
State the approximate value of the membrane potential at X.
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22M.2.SL.TZ2.1a.iii:
Compare and contrast the cumulative increase in mass of the three groups of colonies once they were placed in the field.
- 21M.1.HL.TZ1.23: Which structural feature enables saltatory conduction? A. Nodes of Ranvier between Schwann...
- 21M.2.HL.TZ2.2a.iii: On the diagrams, label with a letter P a location where a neonicotinoid pesticide could bind.
- 20N.1.HL.TZ0.25: The graph shows the changing membrane potential during a nerve impulse. Which letter...
- 18M.1.HL.TZ2.36: Neurons transmit electrical impulses. Which statement describes part of this process? A. K+...
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21M.2.SL.TZ2.1g:
Explain how neonicotinoids affect synaptic transmission in insects.
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22M.1.SL.TZ2.28:
The diagram shows the synaptic transmission of nerve impulses by the neurotransmitter acetylcholine.
[Source: Zhang, X. A Mathematical Model of a Neuron with Synapses based on Physiology. Nat Prec (2008).
https://doi.org/10.1038/npre.2008.1703.1 available at https://www.nature.com/articles/npre.2008.1703.1
Source adapted.]What is the fate of acetylcholine immediately after binding to the receptor?
A. It is pumped into the postsynaptic neuron.
B. It diffuses into the presynaptic neuron.
C. It is broken down in the synaptic cleft.
D. It binds to another receptor in the postsynaptic neuron.
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18M.1.SL.TZ1.2:
Common pesticides used by gardeners contain neonicotinoids.
[Source: © International Baccalaureate Organization 2018]
What is the effect of a neonicotinoid pesticide on the transmission of a nerve impulse between neurons in an insect?
A. It prevents the release of acetylcholine from the presynaptic membrane.
B. It widens the synaptic cleft so diffusion of acetylcholine across the gap is slower.
C. It irreversibly binds with acetylcholine receptors on the postsynaptic membrane.
D. It interferes with the enzymatic breakdown of acetylcholine by acetylcholinesterase.
- 18N.1.HL.TZ0.25: The diagram shows an action potential moving along a neuron. Which part of the diagram...
- 22M.2.SL.TZ2.1a.ii: State the cumulative increase in the mass of control colonies at 7 weeks.
- 22M.2.SL.TZ2.1a.iv: Suggest a reason for the changes in mass in the colonies between weeks 6 and 8.
- 22M.2.SL.TZ2.1c.i: Identify the species whose eggs are most affected by a high dose of neonicotinoid.
- 18M.1.SL.TZ1.3: How does potassium move across the membrane of a neuron during repolarization? A. Simple...
- 17M.1.SL.TZ1.24: The diagram below shows part of the membrane of a neuron. What stage of the action potential...
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19M.1.SL.TZ2.28:
The diagram shows a motor neuron.
[Source: © International Baccalaureate Organization 2019]
What are the biochemical nature and function of the myelin sheath?
A. The myelin sheath is mainly protein which allows growth of the axon.
B. The myelin sheath is mainly protein which acts as membrane carriers.
C. The myelin sheath is mainly lipid which allows saltatory conduction.
D. The myelin sheath is mainly lipid which provides an energy source.
- 19M.2.SL.TZ2.1d: Distinguish between the effects of the mouse alarm compound and the effects of the control...
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19M.1.SL.TZ1.29:
The diagram shows a graph of an action potential.
[Source: https://www.ncbi.nlm.nih.gov/books/NBK538143/figure/article-17127.image.f1/?report=objectonly
Physiology, Action Potential by Michael H. Grider and Carolyn S. Glaubensklee.
Copyright © 2019, StatPearls Publishing LLC
https://creativecommons.org/licenses/by/4.0/]What is happening at X?
A. Sodium channels close.
B. Calcium channels open.
C. Sodium channels open.
D. Potassium channels close.
- 17M.1.SL.TZ1.25: Neurotransmitters are released into the synaptic cleft from the presynaptic neuron and travel...
- 17M.1.HL.TZ2.35: What is essential for conduction of nerve impulses to be saltatory? A. Wrapping of myelin...
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22M.2.SL.TZ2.1b:
Using the data in the graph, predict how the use of neonicotinoid pesticides will affect bumblebee populations.
- 20N.2.HL.TZ0.2c.i: State the name of the structure shown.
- 17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive...
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19M.1.HL.TZ1.24:
The diagram shows a neural synapse in the central nervous system of a honey bee (Apis mellifera).
[Source: © International Baccalaureate Organization 2019]
How do neonicotinoid pesticides cause paralysis and death of honey bees?
A. They destroy I.
B. They bind to II.
C. They inhibit the release of III.
D. They block the activity of IV.
- 20N.2.SL.TZ0.3b.i: State the name of the structure shown.
- 17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
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18M.2.HL.TZ1.6b:
Outline how neurons generate a resting potential.
- 20N.2.HL.TZ0.2c.ii: X indicates the movement of a structure in the neuron. Explain what events trigger this...
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22M.2.SL.TZ1.5d:
Explain how a nerve impulse is passed on to other neurons.
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22M.2.SL.TZ1.5b:
Y is the threshold potential. State what happens when the threshold potential is reached.
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22M.2.SL.TZ2.1a.i:
Describe the effect of neonicotinoid pesticides on the nervous system of insects.
- 21M.2.HL.TZ2.2a.i: On the diagrams, label with a letter H the hydrophilic end of a phospholipid.
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16N.1.HL.TZ0.24:
The decline in European honeybee (Apis mellifera) populations may be linked to neonicotinoid pesticides. What effect do these pesticides have on the nervous system of insects?
A. They prevent acetylcholinesterase from breaking down acetylcholine.
B. They inhibit depolarization in the presynaptic neuron which increases the levels of acetylcholine.
C. They produce an inhibitor that promotes the binding of acetylcholine.
D. They block synaptic transmission by binding with postsynaptic acetylcholine receptors. -
21M.2.HL.TZ2.2d.i:
State the action of the enzyme acetylcholinesterase.
- 22M.1.SL.TZ1.28: The image shows a neuron. What is the function of X? A. Increases the speed of...
- 21M.2.SL.TZ1.4a: Estimate the resting potential for this axon.
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19M.2.SL.TZ2.1b:
Using evidence from the chart, identify, giving a reason, which group of neurons responded most to the chemicals.
- 19M.2.SL.TZ2.1a: State the percentage of G2 neurons in the mice that respond to the fox scent. . . . . . . ....
- 19N.1.SL.TZ0.28: The graph shows an action potential. What is the threshold potential for this cell? A....
- 19M.2.SL.TZ2.1g: The molecular structures of the mouse alarm compound and fox scent are very similar. Suggest...
- 18M.1.SL.TZ2.29: What process is blocked by neonicotinoid pesticides in insects? A. Transmission of the nerve...
- 20N.2.SL.TZ0.3b.ii: X indicates the movement of a structure in the neuron. Explain what events trigger this...
- 19M.2.SL.TZ2.1f: Deduce whether there is a correlation between the neural traces and the percentage of...
- 19M.2.SL.TZ2.1c: State the name of the instrument used to make these traces.
- 17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
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21N.2.HL.TZ0.3c:
Explain the propagation of nerve impulses along the membrane of a neuron.
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21M.2.HL.TZ1.6c:
Compare and contrast hormonal and nervous communication.
- 21M.2.HL.TZ2.2a.ii: On the diagrams, label with a letter E a vesicle involved in exocytosis.
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21M.2.HL.TZ2.2c:
Explain how acetylcholine initiates an action potential in a postsynaptic membrane.
- 21N.1.SL.TZ0.28: The graph shows changes in the membrane potential in an action potential. What is the...
- 17M.1.HL.TZ2.36: If schizophrenia is caused by an overabundance of the neurotransmitters dopamine and...
- 20N.1.SL.TZ0.29: How do neonicotinoid pesticides cause paralysis and death in insects? I. Acetylcholine...
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21M.2.SL.TZ2.1h:
Companies that manufacture neonicotinoid pesticides have argued that they do not cause significant harm to honeybees. Construct an argument, based on the data in this question, for serious concern about the manufacture and use of neonicotinoid pesticides.
- 21M.2.SL.TZ1.4b: Outline the role of the sodium–potassium pump in maintaining the resting potential.
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21M.2.HL.TZ2.2b:
Outline how depolarization of the membrane of an axon occurs.
- 17N.1.HL.TZ0.24: What happens when an action potential reaches motor end plates? A. Calcium ions are absorbed...
- 17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
- 18M.2.SL.TZ2.5c: Explain the events that occur during a nerve impulse and how the impulse is propagated along...
- 18N.1.SL.TZ0.28: The image shows a neuron. Which letter shows the myelin sheath?
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22M.2.SL.TZ2.1d:
Deduce, based on the data presented, whether the levels of neonicotinoids used in agriculture cause direct harm to B. terrestris.
- 17M.1.SL.TZ2.29: If schizophrenia is caused by an overabundance of the neurotransmitters dopamine and...
- 19M.2.SL.TZ2.1e: Compare and contrast the effects of the mouse alarm compound and stoat scent on the G1 neurons.
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21M.1.HL.TZ2.24:
The electron micrograph shows a transverse section through a myelinated neuron.
[Source: Transmission electron micrograph of a myelinated axon. https://commons.wikimedia.org/wiki/File:Myelinated_neuron.jpg. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license (https://creativecommons.org/licenses/by-sa/3.0/deed.en).]
What process is facilitated by the presence of the structure labelled X?
A. Repolarization of the nerve cell membrane
B. Generation of an action potential
C. Saltatory conduction
D. Synaptic transmission
- 21M.1.HL.TZ1.22: Which statement applies to an axon at rest? A. There is no electric potential difference...
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22M.2.SL.TZ2.1c.ii:
Describe the overall effects of low and high doses of neonicotinoid on the egg lengths of all four species.
![https://commons.wikimedia.org/wiki/File:Anatomy_and_physiology_of_animals_Motor_neuron.jpg]](https://commons.wikimedia.org/wiki/File:Anatomy_and_physiology_of_animals_Motor_neuron.jpg%5D){kind=link}
