The diagrams below represent various phases of meiosis - NSC Life Sciences - Question 2 - 2018 - Paper 1
Question 2
The diagrams below represent various phases of meiosis.
2.1 Identify the phase of meiosis in diagram:
(a) A
(b) B
2.1.2 Draw a labelled diagram to show the cells t... show full transcript
Worked Solution & Example Answer:The diagrams below represent various phases of meiosis - NSC Life Sciences - Question 2 - 2018 - Paper 1
Step 1
Identify the phase of meiosis in diagram (a) A
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Answer
The phase of meiosis in diagram A is Prophase.
Step 2
Identify the phase of meiosis in diagram (b) B
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Answer
The phase of meiosis in diagram B is Anaphase.
Step 3
Draw a labelled diagram to show the cells that will be formed at the end of meiosis from the cell in diagram C
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The cells formed at the end of meiosis from the cell in diagram C will consist of two daughter cells, each containing one set of replicated chromosomes. The labelled diagram should include:
Cell membrane
Nucleus
Nucleolus
Chromosomes
Cytoplasm
Step 4
State ONE function of testosterone not mentioned in the extract.
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Testosterone stimulates the development of secondary male characteristics, such as deeper voice and increased muscle mass.
Step 5
According to the extract, state TWO ways in which cryptorchidism is treated.
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Administering testosterone/hormonal treatment.
Surgery.
Step 6
What percentage of premature male babies are born with cryptorchidism?
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Approximately 10% of premature male babies are born with cryptorchidism.
Step 7
From the extract, give ONE reason, other than infertility, why cryptorchidism needs to be treated if the condition is not resolved naturally.
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It increases the risk of testicular cancer.
Step 8
Explain why undescended testes may lead to infertility in young males.
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The temperature of the testes may be too high, which can affect sperm maturation and lead to poor blood circulation, thereby impacting spermatogenesis.
Step 9
Give ONE reason why the women were asked for their height and mass.
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To calculate their BMI (Body Mass Index).
Step 10
Determine how many of the participants were subfertile smokers with a BMI ≥30. Show ALL calculations.
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Based on the graph, 41% of women with a BMI ≥30 were subfertile. To calculate this:
Total number of subfertile women = 1 510
Subfertile smokers with BMI ≥30 = 41% of 1 510 = 0.41 * 1 510 = 619.1, which rounds to 619.
Step 11
Suggest why only women with planned pregnancies were included in the investigation.
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Only women with planned pregnancies can indicate how long it took them to fall pregnant accurately.
Step 12
State ONE factor that was kept constant in this investigation.
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All the women were at least 20 years old.
Step 13
Based on the information in the graph on page 12, what advice should be given to women who want to increase their chances of falling pregnant?
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Do not smoke if your BMI is <20 or ≥30.
Step 14
The investigation was carried out in another country and the results below were obtained.
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Similar/same results were obtained in the second/repeated investigation.
Step 15
Give ONE function of part (a) A.
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Transmits sound waves to the tympanic membrane.
Step 16
Give ONE function of part (b) E.
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Equalises pressure on either side of the tympanic membrane.
Step 17
Write down only the LETTER of the part where sound is transmitted in the form of (a) A pressure wave in a liquid.
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C.
Step 18
Write down only the LETTER of the part where sound is transmitted in the form of (b) An electrical impulse.
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D.
Step 19
Explain the effect if the receptors in region C are damaged.
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The receptors cannot convert the stimuli into impulses. As a result, fewer impulses are transmitted to the cerebrum, impairing hearing.
Step 20
Describe how the parts of the middle ear, including the membranes, assist with amplifying sounds.
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The sound vibrations are transmitted from the large tympanic membrane through the ossicles, which are arranged from largest to smallest. This arrangement concentrates the vibrations, amplifying them.
Step 21
Describe the role of the semi-circular canals in maintaining balance.
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A change in speed/direction of movement stimulates the cristae. This sends signals to the cerebellum, which then commands the muscles to restore balance.
