Chapter 15

Question 1

Describe a drug

Answer 1

a substance taken into the body that modifies or affects chemical reactions in the body

Question 2

Describe the use of antibiotics

Answer 2

treatment of bacterial infections – destroy bacteria without harming the host:
- prevent bacteria from reproducing
- cause them to burst open
- interfere with protein synthesis – stop bacterial growth

Question 3

Explain resistance of bacteria

Answer 3

– some bacteria can mutate into forms that are resistant to these drugs, reducing the effectiveness of antibiotics

– when bacteria are initially exposed to an antibiotic, those most susceptible to the antibiotic will die quickly, leaving any surviving bacteria that mutate and pass on their resistant features to succeeding generations – reproduce rapidly, in 20 minutes

Question 3

Why aren’t antibiotics used to treat viral infections

Answer 3

antibiotics work by disrupting structures in bacteria such as cell walls and membranes, or processes associated with protein synthesis and replication of DNA. viruses have totally different structures and characteristics to bacteria, so antibiotics do not affect them

Question 4

Explain how to limit the development of resistant bacteria
such as MRSA

Answer 4

– antibiotics should be used only when essential, otherwise there could be a build-up of a resistant strain of bacteria; the drug - resistance can be passed from harmless bacteria to pathogens

– a course of antibiotics should always be completed and not used in a diluted form; otherwise, bacteria that have been exposed to the antibiotic but not killed may mutate into resistant forms