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BIOLOGY, M5 2023 HSC 33

Mechanisms of reproduction for both humans and generalised fungi are shown in the diagrams.

 


 

Describe the similarities and differences of reproduction in humans and generalised fungi.  (4 marks)

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Similarities

→ Both human and fungi reproduction use mitosis and meiosis.

→ Both human and fungi reproduction form zygotes with chromosomes from two different individuals.

Differences

→ Humans reproduce through sexual reproduction while fungi use asexual spores or sexual reproduction.

→ Humans produce egg and sperm cells which fuse to form a zygote, while fungi produce spores which germinate to produce mycelium which can be formed sexually or asexually.

Show Worked Solution

Similarities

→ Both human and fungi reproduction use mitosis and meiosis.

→ Both human and fungi reproduction form zygotes with chromosomes from two different individuals.

Differences

→ Humans reproduce through sexual reproduction while fungi use asexual spores or sexual reproduction.

→ Humans produce egg and sperm cells which fuse to form a zygote, while fungi produce spores which germinate to produce mycelium which can be formed sexually or asexually.

Mean mark 56%.

BIOLOGY, M5 EQ-Bank 22

  1. The following data shows the average amount of Human Chorionic Gonadotropin (hCG) produced by pregnant women.
      

    Use the information provided to graph the levels of hCG in a normal pregnancy.   (3 marks)
     
     

  2. Describe the role and changes in levels of a hormone in pregnancy.   (3 marks)

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a.   

b.   The role and changes in levels of hormones in pregnancy.

→ Progesterone is a sex hormone which is initially secreted by the corpus leuteum after ovulation to thicken the endometrium for implantation.

→ Once the placenta has developed, it then increases the progesterone levels which maintain the pregnancy.

→ Progesterone levels eventually drop in the last stage of pregnancy to facilitate delivery.
  

Answers could also include information about other hormones including

→ Oestrogen

→ hCG

Show Worked Solution

a.   

b.   The role and changes in levels of hormones in pregnancy.

→ Progesterone is a sex hormone which is initially secreted by the corpus leuteum after ovulation to thicken the endometrium for implantation.

→ Once the placenta has developed, it then increases the progesterone levels which maintain the pregnancy.

→ Progesterone levels eventually drop in the last stage of pregnancy to facilitate delivery.
  

Answers could also include information about other hormones including

→ Oestrogen

→ hCG

BIOLOGY, M5 2019 HSC 18 MC

The diagram shows the effect of the hormone oxytocin on the uterus during the birth of a mammal.
 

 Which of the following best identifies and explains the feedback loop demonstrated in the diagram?
 

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`B`

Show Worked Solution

→ Oxytocin is a chemical which maintains cervical contractions by releasing more oxytocin when the cervix is contracted, a property of a positive feedback mechanism.

`=>B`


♦♦ Mean mark 31%.

BIOLOGY, M5 2020 HSC 25

Students tested the hypothesis that the number of eggs/young produced was greater in animals using external fertilisation than those using internal fertilisation. They obtained the following data from secondary sources.
 

  1. What conclusion can be drawn from the data? Justify your answer.   (3 marks)

  2. Justify an improvement to the students' experimental design to test the same hypothesis.   (2 marks)

  3. Explain ONE advantage for animals of using external fertilisation.   (2 marks)

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a.   Conclusion: There is little difference

→ The numbers of eggs laid/young born between different species was similar in both external and internal animals (43, 40).

→ The standard deviation (variability of the data) was significantly high (55, 32).

→ These two factors mean that students may conclude there is little to no difference between the number of young produced and the mode of fertilisation.
 

b.   Potential adjustments to improve design

→ Students have selected only twelve species to use in their investigation, which has led to similar results in both internal and external fertilisation.

→ A much larger number of species should be included in a follow up investigation to increase the likelihood of yielding more accurate results.
 

c.   Successful answers should include one of the following:

→ External fertilisation will expend less energy on gestation, as it occurs outside the body.

→ The large number of young produced in external fertilisation will ensure continuity of the species with minimal parental guidance.

Show Worked Solution

a.   Conclusion: There is little difference

→ The numbers of eggs laid/young born between different species was similar in both external and internal animals (43, 40).

→ The standard deviation (variability of the data) was significantly high (55, 32).

→ These two factors mean that students may conclude there is little to no difference between the number of young produced and the mode of fertilisation.


Mean mark (a) 51%.

b.   Potential adjustments to improve design

→ Students have selected only twelve species to use in their investigation, which has led to similar results in both internal and external fertilisation.

→ A much larger number of species should be included in a follow up investigation to increase the likelihood of yielding more accurate results.


♦♦ Mean mark (b) 38%.

c.   Successful answers should include one of the following:

→ External fertilisation will expend less energy on gestation, as it occurs outside the body.

→ The large number of young produced in external fertilisation will ensure continuity of the species with minimal parental guidance.

BIOLOGY, M5 2020 HSC 3 MC

The following four events occur during reproduction in a placental mammal.

  1. Fertilisation
  2. Implantation
  3. Ovulation
  4. Placental formation

In which order do these events occur?

  1. 2, 1, 3, 4
  2. 2, 4, 1, 3
  3. 3, 1, 2, 4
  4. 3, 2, 4, 1
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`C`

Show Worked Solution

→ Ovulation (the production of the female gamete) must occur first, followed by fertilisation of the gamete.

→ Once it is fertilised, it implants itself in the uterine wall, followed by the formation of the placenta.

`=>C`

BIOLOGY, M5 2021 HSC 23

Ovulation in women is associated with a rapid increase in luteinising hormone (LH). Test strips can be used to detect high levels of LH in urine. Once a test strip is used, a control line should appear and the presence of a test line indicates high levels of LH in urine. The image below represents four different results that were obtained.
 

Which of the results indicates a valid test which shows that ovulation is NOT occurring? Justify your answer.   (3 marks)

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→ Test strips 3 and 4 do not contain a control line, therefore are invalid.

→ Test strip 2 contains a control line but no test line, indicating that there was no LH surge.

→ Therefore, test strip 2 indicates a valid negative result that shows ovulation is not occurring.

Show Worked Solution

→ Test strips 3 and 4 do not contain a control line, therefore are invalid.

→ Test strip 2 contains a control line but no test line, indicating that there was no LH surge.

→ Therefore, test strip 2 indicates a valid negative result that shows ovulation is not occurring.

BIOLOGY, M5 2021 HSC 12 MC

The graph shows the levels of three hormones, oestrogen, progesterone and human chorionic gonadotrophin (HCG), measured in the blood of a woman during her pregnancy.
 

Which statement can be inferred from the graph?

  1. Birth occurred about week 36.
  2. Fertilisation occurred at day 0.
  3. Implantation occurred about week 4.
  4. The placenta was formed about week 24.
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`C`

Show Worked Solution

→ HCG is released once the embryo has implanted.

→ Implantation occurs approximately 5-6 days after fertilisation which can take place when ovulation occurs, approximately 2 weeks after the menstrual cycle ends.

`=>C`

♦ Mean mark 49%.

BIOLOGY, M5 2021 HSC 2 MC

Which of the following photographs shows an example of sexual reproduction?
 

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`D`

Show Worked Solution

By Elimination

→ Budding in fungi, binary fission in bacteria and runners in plants are all examples of asexual reproduction (Eliminate A, B and C).

→ Frog spawning requires a female to lay eggs and a male frog to fertilise them with sperm.

`=>D`