Biology 9700 · AS & A Level · Antibiotics

Antibiotics — practice question

Treatment for people with active tuberculosis (TB) continues for six months and uses a mixture of antibiotics. This is usually highly effective when the person has a susceptible (non-resistant) strain of $\textit{Mycobacterium tuberculosis}$, the organism that causes TB. Table 2.1 gives one recommended treatment plan based on combined antibiotics.
(a)[4]

Susceptible strains of $\textit{Mycobacterium tuberculosis}$ will be destroyed by any one of the antibiotics listed in Table 2.1. However, combination treatment is preferred because it is one way to reduce the effect of antibiotic resistance on society. Using Table 2.1, explain how combination treatment for TB can reduce the effect of antibiotic resistance more effectively than single-antibiotic treatment.

(b(i))[1]

RNA polymerase catalyses the production of messenger RNA (mRNA) from DNA. State the name of this process.

(b(ii))[3]

As RNA is being formed, several events take place that depend on RNA polymerase. Suggest ways in which rifampicin can affect the activity of RNA polymerase.

(c(i))[1]

Complete Table 2.2 to show the amino acid changes that have occurred in strains F and G.

(c(ii))[1]

Using Table 2.2, list the strains of Mycobacterium tuberculosis that show the greatest resistance to rifampicin.

(c(iii))[3]

Suggest reasons to explain why strains C, D and E show: • resistance to rifampicin • different levels of resistance to rifampicin.

(i)[1]

Complete Table 2.2 to show the amino acid changes that have occurred in strains F and G.

(ii)[1]

Using Table 2.2, list the strains of $M.\ tuberculosis$ that show the greatest resistance to rifampicin.

(iii)[3]

Suggest reasons to explain why strains C, D and E show: • resistance to rifampicin • different levels of resistance to rifampicin.

Worked solution & mark scheme

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