Biology 9700 · AS & A Level · Control and coordination in mammals

Control and coordination in mammals — practice question

(a)[2]

Outline the biological mechanism behind the effect of the contraceptive pill.

(b)

In Uganda, a large number of children acquire HIV from their mothers. This is known as vertical HIV transmission. Uganda has used two approaches to try to reduce vertical HIV transmission: increasing the use of antiretroviral drugs (ARVs) by HIV-infected pregnant women, and cutting, through contraception, the number of unwanted pregnancies.

(b(i))[2]

It is estimated that, had no ARVs been used in 2007, 27200 children would have been born with HIV infection. Calculate how many children were actually born with HIV infection in 2007. Show your working.

(b(ii))[2]

Using Table 5.1, explain how ARVs and contraception differ in their effects on the number of pregnancies in HIV-infected women.

(b(iii))[3]

Only a limited budget is available for HIV prevention in Uganda. With reference to Table 5.1, suggest reasons for allocating at least as much money to improving access to contraception as to supplying ARVs to HIV-infected pregnant women.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Has oestrogen and progesterone, or progesterone alone

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