The diagram below represents a germinating seed - NSC Life Sciences - Question 3 - 2017 - Paper 1
Question 3
The diagram below represents a germinating seed. Assume that the radicle and plumule were exposed to uniform light from all directions.
3.1.1 Define tropism.
3.1.2... show full transcript
Worked Solution & Example Answer:The diagram below represents a germinating seed - NSC Life Sciences - Question 3 - 2017 - Paper 1
Step 1
Define tropism.
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Answer
Tropism is the growth of a plant or part of a plant in response to a stimulus, which can be directional (toward or away from the stimulus).
Step 2
Draw a labelled diagram to show the position of the radicle and plumule in the seedling one week later.
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Answer
The diagram should depict the radicle (young root) growing downwards and the plumule (young stem) growing upwards with leaves branching off. The labels should clearly indicate each part.
Step 3
State where auxins are produced in a plant.
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Auxins are produced in the tip of the stem, root apical meristem, and terminal bud.
Step 4
Describe the effect of auxins on a plant stem that is exposed to unilateral light.
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Auxins promote cell elongation on the side of the stem that is away from the light. This causes the stem to bend towards the direction of the light source, optimizing light absorption for photosynthesis.
Step 5
Name the group(s) (A, B or C) in which the average mass of the rats increased.
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Answer
The average mass of the rats increased in Group A and Group C.
Step 6
For this investigation state the:
(a) Independent variable
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The independent variable is the diet the rats received.
Step 7
(b) Dependent variable and how it was measured.
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The dependent variable is the metabolic rate, which was measured by the change in mass and oxygen consumption of the rats.
Step 8
Arrange the diets (X, Y and Z) in order of increasing amounts of thyroxin that would be found in the rats after they were given these diets.
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Answer
The order of the diets in increasing amounts of thyroxin is: X, Z, Y.
Step 9
Which group (B or C) was given diet Y?
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Group B was given diet Y.
Step 10
Refer to changes in mass and oxygen consumption of the rats in the table above. Explain your answer to QUESTION 3.3.4.
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Answer
The mass of the rats that received diet Y decreased, indicating that energy was used for metabolism due to the presence of thyroxin. Additionally, the oxygen consumption was highest in group B, which suggests that thyroxin increased metabolic rate.
Step 11
Identify:
(a) B
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B is the Auditory nerve.
Step 12
(b) D
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D is the Round window (Fenestra rotunda).
Step 13
Which part of the brain will receive impulses from part C?
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Part C sends impulses to the Cerebellum.
Step 14
Describe the role of the semi-circular canals in maintaining balance.
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The semi-circular canals detect changes in speed and direction via the cristae within them, which respond to the movement of fluid (endolymph) during changes in head position, helping maintain balance.
Step 15
Describe how an increased production of mucus in the nose and throat may lead to the bursting of part E.
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Increased mucus production can block the Eustachian tube, preventing air from entering or leaving the middle ear. This leads to pressure imbalance, which can cause part E to burst due to excess pressure.
Step 16
Explain why fusion of the structures at A may lead to hearing loss.
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Fusion of the structures at A can prevent the ossicles from vibrating effectively. If the ossicles do not vibrate, sound waves cannot be transmitted to the cochlea, leading to reduced or lost hearing capability.
