3.1.1 During which month was the abscisic acid concentration the lowest?
3.1.2 Explain the trend of the graph from March to May - NSC Life Sciences - Question 3 - 2023 - Paper 1
Question 3
3.1.1 During which month was the abscisic acid concentration the lowest?
3.1.2 Explain the trend of the graph from March to May.
3.1.3 Suggest ONE reason for the d... show full transcript
Worked Solution & Example Answer:3.1.1 During which month was the abscisic acid concentration the lowest?
3.1.2 Explain the trend of the graph from March to May - NSC Life Sciences - Question 3 - 2023 - Paper 1
Step 1
During which month was the abscisic acid concentration the lowest?
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Answer
The abscisic acid concentration was the lowest in November.
Step 2
Explain the trend of the graph from March to May.
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Answer
From March to May, the abscisic acid concentration shows an increase, reaching its peak around May. This signifies that the tree is preparing for leaf shedding in the following months.
Step 3
Suggest ONE reason for the dormancy in cherry trees during the winter months.
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Answer
Cherry trees enter dormancy in winter due to reduced photosynthesis resulting from less sunlight and cold temperatures, which lowers their energy demand.
Step 4
Describe the role of auxins in roots.
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Answer
Auxins play a critical role in the development of roots. They promote downward growth, leading to root elongation and positively influencing geotropic responses, thereby aiding the plant in acquiring water and nutrients.
Step 5
Explain the difference in the response of the stem and the roots after a few days.
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Answer
In response to horizontal placement, auxins accumulate on the lower side of the stem, prompting it to bend upwards as it grows towards the light. In contrast, auxins in the roots stimulate growth on the lower side, causing the roots to bend downwards.
Step 6
Name the gland that secretes aldosterone.
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Answer
The gland that secretes aldosterone is the adrenal gland.
Step 7
Identify the: (a) Independent variable
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(a) The independent variable is the aldosterone level.
Step 8
(b) Dependent variable
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(b) The dependent variable is the blood pressure.
Step 9
Give TWO reasons why the results of the investigation may be considered reliable.
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The results may be considered reliable because 1,688 volunteers were involved, and the measurements were repeated four times for each participant, ensuring consistent data.
Step 10
Explain TWO reasons why it was important for the participants to follow the same diet during the investigation.
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It is important for participants to follow the same diet to ensure that dietary factors do not influence the blood pressure measurements, hence maintaining experimental control.
Step 11
Explain why the participants’ blood pressure was measured before the start of the investigation.
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Participants’ blood pressure was measured before the study to establish a baseline reading for comparison with post-injection values.
Step 12
Explain why the levels of salt in the urine of participants is expected to decrease after being injected with aldosterone.
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After injecting aldosterone, the permeability of renal tubules increases for sodium. Consequently, more sodium is reabsorbed, leading to a decrease in salt levels in the urine.
Step 13
Describe how the secretion of adrenaline causes increased energy production in an emergency situation.
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In an emergency, adrenaline stimulates the conversion of glycogen to glucose, which increases blood glucose levels. This process also heightens metabolic activity, leading to increased blood flow and oxygen transport, thereby enhancing overall energy production.
Step 14
Identify structure F.
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Structure F is the iris.
Step 15
State TWO functions of fluid A.
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Fluid A serves to maintain the shape of the eye and plays a role in the refraction of light.
Step 16
Describe the structural difference between area B and area C.
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Area B contains a high concentration of photoreceptors (rods and cones), while area C has no photoreceptors, making it less sensitive to light.
Step 17
Name the visual defect that occurs when the curvature of part E is uneven.
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The visual defect caused by an uneven curvature of part E is known as astigmatism.
Step 18
Explain how the sight of a person will be affected if cataracts developed in part D.
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Cataracts in part D would cause the lens to become cloudy, obstructing light transmission and resulting in blurred vision or decreased clarity.
Step 19
Describe the process of accommodation that takes place when an object is less than 6 metres away from the eye.
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When an object is closer than 6 metres, the ciliary muscles contract causing the lens to become thicker to increase its refractive power, enabling clear vision of the nearby object.
