Biology 9700 · AS & A Level · Principles of genetic technology

Principles of genetic technology — practice question

In order to prepare infertile women for in-vitro fertilisation (IVF), the development and maturation of a number of ovarian follicles must be encouraged. This is achieved by administering daily injections of the glycoprotein hormone follicle stimulating hormone (FSH). Each FSH molecule has quaternary structure and is formed from two different polypeptide chains, $\alpha$ and $\beta$.
(a)[1]

Explain what quaternary structure means.

(b)[3]

Human FSH can be obtained from women’s urine (u-hFSH). A method using monoclonal antibodies is employed to make purified u-hFSH. Suggest how monoclonal antibodies can be used to separate purified u-hFSH from urine.

(c)[1]

Recombinant human FSH (r-hFSH) can be made by inserting the genes coding for the $\alpha$ and $\beta$ polypeptide chains of FSH into mammalian ovary cells. Suggest why mammalian cells are needed to make r-hFSH, rather than bacterial cells.

(d)[3]

During IVF treatment, a second hormone, human chorionic gonadotrophin (hCG), is injected after the mature ovarian follicles (Graafian follicles) have developed. Draw a labelled diagram showing the structure of a mature ovarian follicle.

(e(i))[4]

The performance of r-hFSH was compared with that of u-hFSH. Women in the study were randomly split into two groups and given either r-hFSH or u-hFSH. The differences between the two groups of women after FSH treatment are shown in Table 2.1. With reference to Table 2.1, compare the effects of treatment with r-hFSH and u-hFSH and suggest explanations for the differences.

(e(ii))[2]

The probability of the results for the mean number of mature follicles per woman happening by chance is $< 0.002$. Explain what is meant by this probability.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: More than one polypeptide chain

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