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Figure 4 shows how hormone concentrations vary during a normal human menstrual cycle if a woman does not become pregnant - AQA - GCSE Biology Combined Science - Question 6 - 2018 - Paper 2
Question 6
Figure 4 shows how hormone concentrations vary during a normal human menstrual cycle if a woman does not become pregnant. Calculate the rate of increase in LH con... show full transcript
Worked Solution & Example Answer:Figure 4 shows how hormone concentrations vary during a normal human menstrual cycle if a woman does not become pregnant - AQA - GCSE Biology Combined Science - Question 6 - 2018 - Paper 2
Step 1
Calculate the rate of increase in LH concentration between day 9 and day 12
Answer
To find the rate of increase of LH concentration between day 9 and day 12, first, we need to extract the LH values from both days from Figure 4.
From the graph:
- On day 9, LH concentration is approximately 33 arbitrary units.
- On day 12, LH concentration is approximately 72 arbitrary units.
The increase in LH concentration is:
Now, to find the number of hours from day 9 to day 12, we calculate:
Finally, the rate of increase is calculated as follows:
ext{Rate} = rac{ ext{Increase}}{ ext{Time}} = rac{39}{72} ext{ arbitrary units per hour} \\ ext{Rate} ext{ (to 2 significant figures)} = 0.54 ext{ arbitrary units per hour}.
Step 2
Describe the sequence of hormone interactions in the menstrual cycle.
Answer
During the menstrual cycle, hormones interact in a specific sequence:
- FSH (Follicle Stimulating Hormone): Produced by the pituitary gland, stimulates the ovaries to mature an egg.
- Oestrogen: Released by the developing follicles in the ovaries, it causes the thickening of the uterus lining during the first half of the cycle.
- LH (Luteinizing Hormone): The surge of oestrogen from the mature follicle stimulates the pituitary gland to release LH, which triggers ovulation (day 14).
- Progesterone: After ovulation, the empty follicle transforms into the corpus luteum, which secretes progesterone to maintain the uterine lining.
- If there is no pregnancy, progesterone levels fall, leading to menstruation.
Step 3
Suggest one advantage of using a progesterone patch rather than a progesterone oral contraceptive.
Answer
One advantage of using a progesterone patch is that it has a lower dose of the hormone compared to oral contraceptives, resulting in fewer side effects. Additionally, the patch lasts longer and does not require daily administration, which enhances convenience for the user.