Hormones are important for regulating the menstrual cycle - AQA - GCSE Biology - Question 7 - 2023 - Paper 2

To find the number of follicles, we first calculate the volume of one follicle:

1. The radius (r) of a follicle is half of the diameter = ( \frac{22}{2} = 11 ) mm.

2. Using the formula for the volume of a sphere: $V = \frac{4}{3} \pi r^{3} = \frac{4}{3} \times 3.14 \times (11)^{3}$

3. Calculating gives: $V \approx 5572.45 \text{ mm}^3$

4. The total volume of follicles at day 11 from Figure 12 is 39,000 mm³.

5. Therefore, the number of follicles is: $\frac{39000}{5572.45} \approx 7$

Thus, the answer is 7.

The lack of FSH in the woman's blood prevents the development of follicles in the ovaries. Without developing follicles, the production of oestrogen is also reduced. Oestrogen is crucial for the development of breast tissue; hence, its absence leads to underdeveloped breasts.

To show how the woman's parents could have a child that does not produce FSH, we can draw a Punnett square diagram using the following genotypes:

• Let the mother's genotype be ( hh ) (homozygous recessive for not producing FSH) and the father's genotype be ( HH ) (homozygous dominant for producing FSH).

The possible gametes are:

• Mother: ( h )
• Father: ( H )

The Punnett square is: [ \begin{array}{c|c|c} & H & H \ \hline h & Hh & Hh \ \hline h & Hh & Hh \ \end{array} ]

All offspring would be ( Hh ), which means they could produce FSH. However, if we assume one parent carries a recessive allele, the possibility of an offspring being ( hh ) exists, leading to a child that does not produce FSH.

In this scenario, the father is heterozygous (( Hh )), meaning he has one allele for producing FSH and one for not producing it. If the mother has genotype ( hh ), then when we perform the genetic cross, the possible offspring genotypes are:

• From ( H ) (father) and ( h ) (mother): ( Hh ) - can produce FSH
• From ( h ) (father) and ( h ) (mother): ( hh ) - cannot produce FSH.

Thus, the ratio of producing to non-producing FSH children is 1:1, giving a probability of 0.5 for the child to be able to produce FSH.