B6 - Preventing and treating disease

Question 1

B6 - Explain the steps that must be taken before a drug can be sold on the open market.

Answer 1

Tested on cells and tissues.

Tested on animals.

Tested on small numbers of healthy volunteers (low doses).

Tested on small numbers of sick patients.

Patients given either the drug or placebo (double blind trial)

Tested on larger numbers of sick patients (double blind trial).

Drug tested for toxicity, efficacy and dose at each stage.

The results will then be analysed to check if they are valid/to avoid bias

Question 2

B6 - Explain how a vaccination prevents infection

Answer 2

Vaccines use dead/inactive forms of pathogens.

Immune system makes antibodies.

Antibodies kill the pathogen.

If you encounter a live form of the pathogen, the right antibodies are synthesised quickly because your immune system remembers the correct ones.

This prevents you from becoming infected.

Question 3

B6 - Explain how the overuse of an antibiotic can lead to resistant strains of bacteria.

Answer 3

A bacteria mutates in a way that means it is resistant.

This resistant bacteria is not able to be treated.

Unmutated bacteria die.

The mutated bacteria multiplies and spreads quickly.