Chapter 7 Set 4

Question 1

What are Antibiotics?

Answer 1

Class of drugs used to fight micro-organisms – usually bacteria.

Question 2

Are antibiotics generally preventive?

Answer 2

Generally not preventative – they are given after infection to help kill the pathogen

Question 3

List the 3 classes of antibiotics? (Not too important)

Answer 3

Penicillins: prevent bacteria from developing cell walls, therefore inhibiting reproduction

Actinomycins: interfere with protein synthesis in bacterial cells

Cephalosporins: interfere with bacterial cell wall synthesis

Question 4

List the two main types of antibiotics

Answer 4

• Bactericidal
• Bacteriostatic

Question 5

How do Bactericidal Antibiotics work?

Answer 5

kill bacteria by:
Inhibiting cell wall synthesis
Inhibiting bacterial enzymes
Inhibiting protein translation within the bacterium

Question 6

How do Bacteriostatic Antibiotics work?

Answer 6

Prevent bacteria from multiplying while the immune system deals with them.
This is done by:
Inhibit bacterial protein production
Inhibiting bacterial DNA replication
Interfering with other aspects of bacterial metabolism

Question 7

What is the difference between broad-spectrum and narrow-spectrum antibiotics?

Answer 7

Broad spectrum:
Work against a wide range of bacterial types.

Narrow-spectrum
Effective against a narrow range.

Question 8

Describe why antibiotic resistance occurs?

Answer 8

Bacteria evolve over time, to become resistant to antibiotics.

Question 9

What are 3 factors that contribute to antibiotic restistance?

Answer 9

• Overuse of antibiotics, even when not necessary.
• Agricultural use as ‘growth promoters’ in livestock.
• Incorrect prescribing: giving an antibiotic that won’t work, or as a preventative without good reason.

Question 10

What are Antivirals made for?

Answer 10

Specifically for viral infections.

Question 11

Why is it difficult to find drugs for antivirals?

Answer 11

This is because a virus enters cells so any drug that interferes with virus may also harm host cell.

Question 12

What do antivirals do to viruses rather than immediately kill it?

Answer 12

Antivirals inhibit development of virus, rather than killing it.

Question 13

What are some examples of antivirals?

Answer 13

• “Zovirax” (acyclovir) – herpes
• Interferons – Hepatitis B
• AZT (azidothymidine) - HIV
• “Tamiflu” (Oseltamivir) - influenza