| Date | November 2016 | Marks available | 2 | Reference code | 16N.3.HL.TZ0.4 |
| Level | Higher level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
| Command term | Suggest | Question number | 4 | Adapted from | N/A |
Question
Defects in the formation of synapses could be the cause of neurological disorders such as Alzheimer’s disease that affects the ability to think and remember clearly. It is more frequent in people older than 65 years of age. The graph shows the changes in synapse number over time. The diagram shows activity-related neural development.
State what happens to unused neurons.
Predict how mental activity might delay the onset of Alzheimer’s disease.
Autism appears early in life and affects how a person communicates and relates to others. There is evidence that autism could be caused by a surplus of synapses. Using all of the information provided, suggest two possible causes of a surplus of synapses in people with autism.
Markscheme
neuron pruning
OR
synapses removed
Do not accept “apoptosis”.
a. more synapses maintained with stimulation/mental activity/OWTTE
b. strong mental activity prevents «neuron» pruning
a. most synapses are formed during childhood/before birth
OR
first years of childhood most important for brain development
b. more synapses «than normal» may be formed «during childhood/before birth in autism»
c. «in autism» pruning of neurons does not occur «causing excess of synapses»
OR
normal synapse elimination does not remove extra synapses
Examiners report
Syllabus sections
- 20N.3.HL.TZ0.4c: Suggest what can happen to neurons that are unused in the nervous system.
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20N.3.HL.TZ0.4a:
Describe the changes occurring in this neuron from day 1 to day 2.
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18M.3.HL.TZ1.4a:
The diagram shows one of the stages in neurulation.
Describe what happens next in neurulation.
- 17N.3.HL.TZ0.07b: Outline how the human brain can reorganize itself following a stroke.
- 17M.3.SL.TZ2.4a: Label the parts I and II on the images.
- 19M.3.HL.TZ1.5b: State what would occur in the embryo immediately after stage IV.
- 17M.3.HL.TZ1.4b: Outline the development of axons in immature neurons.
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18M.3.SL.TZ1.5a:
Evaluate the claim that IGF influences turning angle and neuron extension.
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19M.3.SL.TZ2.5d:
Primates belong to the phylum chordata. The neural tube of chordates is formed by the infolding of the ectoderm followed by the elongation of the tube. Outline the process of formation of neurons from this neural tube in primates.
- 19M.3.SL.TZ1.4b: Explain how patient recovery from a stroke illustrates the property of neural plasticity.
- 18N.3.SL.TZ0.5b: Outline the possible changes to this neuron that could happen during the subsequent...
- 18N.3.SL.TZ0.5c: Suggest how the plasticity of the brain can benefit humans.
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17M.3.HL.TZ1.6b:
List the different types of neurons involved in a reflex arc.
- 16N.3.SL.TZ0.5c: Outline how spina bifida could occur during embryonic development.
- 16N.3.HL.TZ0.4b: Predict how mental activity might delay the onset of Alzheimer’s disease.
- 18M.3.HL.TZ1.4c: Explain the process of neural pruning.
- 17M.3.HL.TZ2.4a.iii: State the condition that arises if the closure of structure X is incomplete during embryonic...
- 17M.3.SL.TZ2.4c: State the condition that arises if the closure of structure X is incomplete during embryonic...
- 18M.3.HL.TZ2.4a: Outline how an immature neuron develops an axon.
- 19N.3.SL.TZ0.4b: Identify the part labelled X.
- 19N.3.SL.TZ0.4c: State a consequence of incomplete folding of the neural tube in humans.
- 19N.3.HL.TZ0.4b: Outline the main feature of neural pruning.
- 18M.3.HL.TZ2.4b: Explain neuroplasticity in terms of the developing neurons.
- 19M.3.HL.TZ2.7: Outline the process that could result in spina bifida during neural tube development.
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18M.3.SL.TZ1.5b:
Outline the development of neurons from when they are first formed in the neural tube.
- 17M.3.SL.TZ2.4b: Structure Y will eventually elongate to form two structures. State the names of these two...
- 17M.3.HL.TZ2.4a.i: Label the parts I and II on the images.
- 18N.3.SL.TZ0.5a: Describe the process taking place.
- 16N.3.SL.TZ0.5b: State what occurs to structure X immediately following its formation.
- 19N.3.SL.TZ0.4d: Explain how the nervous system develops from the cells of the neural tube.
- 19N.3.SL.TZ0.4a: State the name of the stage of embryonic development shown in the diagram.
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17N.3.SL.TZ0.07:
The diagrams illustrate changes in synapse density of the cerebral cortex from newborn to adult.
[Source: THE POSTNATAL DEVELOPMENT OF THE HUMAN CEREBRAL CORTEX, VOLUMES IVIII, by Jesse LeRoy Conel, Cambridge, Mass.: Harvard University Press, Copyright © 1939, 1941, 1947, 1951, 1955, 1959, 1963, 1967
by the President and Fellows of Harvard College. Copyright © renewed 1967, 1969, 1975, 1979, 1983, 1987, 1991.]Explain the processes illustrated by the diagrams.
- 19M.3.HL.TZ1.5c: Outline the consequences of incomplete closure of the neural tube in humans.
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20N.3.HL.TZ0.4b:
Suggest other processes that may occur during neural development.
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19M.3.SL.TZ2.4b:
Scientists demonstrated that cinnamon increased neural plasticity in some parts of mouse brains. Explain how neural plasticity could have affected learning in poor performer mice.
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18M.3.HL.TZ1.4b:
Explain the causes of spina bifida in vertebrates.
- 18M.3.SL.TZ2.7: Explain the stages of development and differentiation of neurons.
- 17M.3.HL.TZ2.4a.ii: Structure Y will eventually elongate to form two structures. State the names of these two...
- 16N.3.HL.TZ0.4a: State what happens to unused neurons.
- 19M.3.HL.TZ1.5a: Describe the process occurring in the diagram.
- 19M.3.SL.TZ1.5b: Neurons are initially produced by differentiation in the neural tube. Outline the mechanisms...
- 19M.3.SL.TZ2.4a: Describe how the use of cinnamon changes mouse performance on the Barnes maze.
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19M.3.SL.TZ2.4c:
It has been suggested that cinnamon might be of benefit to patients who are recovering from a stroke. Suggest one advantage of adding cinnamon to the diet of a patient who has suffered a stroke.
- 17M.3.SL.TZ1.4a: Calculate the rate of movement of the neuron cell body between 0 and 5 h. Working should be...
- 17M.3.SL.TZ1.4c: Outline neural pruning.
- 17M.3.SL.TZ1.4b: Suggest a reason for the migration of neurons in the embryonic nervous system.
- 16N.3.SL.TZ0.5a: Outline the process taking place in the diagram.
