Chapter 5 Self-test questions

. Why was penicillin not an immediate success as an antibiotic?

It was only effective against a small number of bacteria.

It was difficult to produce in sufficient quantities.

It was very toxic to the patient.

It couldn't be taken orally.

. What the two broad mechanisms of action of antibiotics?

Bacteriostatic and antiseptic.

Bacteriocidal and virucidal.

Bacteriostatic and bacteriocidal.

Bacteriocidal and antiseptic.

. Which of the following statements is NOT a reason why antiviral medications more difficult to develop than antibiotics?

Viruses mutate rapidly, so antiviral medicines need to be very potent and act quickly to destroy all the viruses.

Viruses are difficult to study under laboratory conditions, making testing of medication difficult.

Viruses are not living cells and so cannot be targeted by medication.

Many anti-viral compounds are also very toxic to human cells.

. Why do doctors often use a cocktail of drugs to treat chronic viral infections like hepatitis C and HIV?

To make sure that, even if the virus mutates and becomes resistant to one of the drugs, the treatment is still effective.

To decrease the length of the course of treatment.

To reduce the risk of side effects to the patient.

To attempt to treat multiple different viruses at once.

. Why are antifungal medications challenging to develop?

Fungal cells bear many similarities to human cells, meaning that compounds which kill fungi will often also damage our own cells.

Fungal cells are so different to other prokaryotic and eukaryotic cells that most compounds simply don't affect them.

Fungi replicate too rapidly to allow effective chemical treatment.

Fungal infections are very rare, making it less economically viable to develop antifungal medication compared to antibiotic.

. Why are pesticides usually applied topically rather than orally?

Pesticides are more easily absorbed from the skin than the GI tract.

To improve patient compliance.

To reduce the risk of side effects to the host.

Pesticides might damage the gut microbiome if taken orally.

. What are the two broad methods of action of antihelminthic drugs?

Vermifugal and vermicidal.

Vermifugal and vermistatic.

Vermicidal and vermistatic.

Vermicidal and antiprotozoal.

. How many different strains of Plasmodium parasites cause malaria worldwide?

2

3

4

5

. Why must care be taken over the use of insecticides in the fight against malaria?

Insecticides are ineffective.

Insecticides are too expensive to use widely.

Insecticides do not affect vectors for malaria.

Insecticides may affect a range of organisms and cause environmental damage.

. What role does an adjuvant play in a vaccine?

It stabilises the antigens and enhances the immune response.

It makes the vaccine effective against more than one pathogen.

It means that the vaccine does not need refrigerating.

It makes the vaccine cheaper.

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