3.1 State ONE change in the nerve tissue of the brain that can cause Alzheimer's disease - NSC Life Sciences - Question 3 - 2023 - Paper 1
Question 3
3.1 State ONE change in the nerve tissue of the brain that can cause Alzheimer's disease.
From the extract, state:
(a) ONE symptom of Alzheimer's disease
(b) A gene... show full transcript
Worked Solution & Example Answer:3.1 State ONE change in the nerve tissue of the brain that can cause Alzheimer's disease - NSC Life Sciences - Question 3 - 2023 - Paper 1
Step 1
State ONE change in the nerve tissue of the brain that can cause Alzheimer's disease.
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Answer
One change in the nerve tissue that can cause Alzheimer's disease is the degeneration or wasting away of nerve tissue.
Step 2
From the extract, state:
(a) ONE symptom of Alzheimer's disease
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Answer
A symptom of Alzheimer's disease is the worsening ability to remember new information.
Step 3
(b) A genetic risk factor
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Answer
A genetic risk factor for Alzheimer's disease is family history.
Step 4
(c) TWO functions of the hippocampus.
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Answer
The hippocampus is responsible for learning and memory, as well as orientation.
Step 5
Name TWO factors that were considered when selecting the participants for this investigation.
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Answer
The two factors considered were that participants were all females and aged between 65 and 75.
Step 6
Explain why this investigation cannot be used to show that regular exercise reduces the risk of Alzheimer's disease.
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This investigation cannot show that regular exercise reduces the risk of Alzheimer's disease because it did not establish a direct relationship between exercise and the prevention of this disease, as no changes in the nervous tissue were measured.
Step 7
Explain how exercise may improve blood flow to the brain and maintain higher-order thinking abilities in people at risk of developing Alzheimer's disease.
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Answer
Exercise may improve blood flow to the brain by dilating blood vessels, which increases oxygen and nutrient delivery. This improvement in circulation helps maintain the volume of the hippocampus, which is critical for cognitive functions, thus preventing a decrease in higher-order thinking abilities.
Step 8
Identify:
(a) Organ X
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Answer
Organ X is the kidney.
Step 9
(b) The system to which the adrenal gland belongs.
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The adrenal gland belongs to the endocrine system.
Step 10
State TWO characteristics of the type of glands that belongs to the system identified in QUESTION 3.2.1(b).
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The adrenal glands release hormones directly into the blood and are ductless.
Step 11
Describe the relationship between the adrenal gland and organ X in maintaining homeostasis when salt levels in the blood are low.
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When salt levels in the blood are low, the adrenal glands are stimulated to secrete more aldosterone, which helps the kidneys reabsorb more salt and thus restore normal salt levels.
Step 12
Explain the effect that a secretion of the pituitary gland will have on organ X when a person experiences dehydration.
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When a person experiences dehydration, the secretion of Antidiuretic Hormone (ADH) from the pituitary gland increases, leading to an increase in the permeability of the renal tubules in the kidney, causing reabsorption of more water and helping to restore hydration.
Step 13
Name the:
(a) Homeostatic mechanism that brings about the change in skin temperature.
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Answer
The homeostatic mechanisms involved are thermoregulation.
Step 14
(b) Part of the brain that is responsible for the mechanism named in QUESTION 3.3.1(a).
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The part of the brain responsible is the hypothalamus.
Step 15
From the diagram, identify the following parts:
(a) P
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Part P is a sweat gland.
Step 16
(b) Q
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Part Q is a capillary.
Step 17
Calculate the percentage decrease in the average skin temperature of the boy before and directly after exercise. Show ALL working.
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Answer
The average skin temperature before exercise is 37.4 °C and after is 35.4 °C. The percentage decrease is calculated as follows:
ext{Percentage Decrease} = rac{37.4 - 35.4}{37.4} imes 100 = 5.35\%.
Step 18
Explain the roles of part P and Q in the change in skin temperature from before exercise to directly after exercise.
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Part P (sweat glands) increases activity to produce sweat, which evaporates to cool the skin. Part Q (capillaries) dilates to increase blood flow to the skin, facilitating heat loss through radiation and convection.
Step 19
For this investigation, state:
(a) Independent variable.
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The independent variable is the presence or absence of auxins.
Step 20
(b) Dependent variable.
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The dependent variable is the growth of lateral branches.
Step 21
Explain why all the plants were exposed to the same environmental conditions.
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All plants were exposed to the same environmental conditions to ensure the validity of the investigation by eliminating external factors that could affect growth.
Step 22
Explain why agar without auxins was used in plant C.
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Agar without auxins was used in plant C to serve as a control, ensuring that any observed effects on growth could be attributed to the presence of auxins in the other plants.
Step 23
State a conclusion for this investigation.
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The presence of auxins stimulates the growth of lateral branches.
