Antibiotic

Question 1

What is antibiotic?

Answer 1

Natural sub obtained from microorganisms;

Inhibit bacterial growth;

Kill bacteria by disrupting metabolism of prok cells

Question 2

Two types of antibiotic and their function

Answer 2

1. Bacteriostatic
   - inhibits growth/cell division
2. Bactericidal
   - kill bacteria undergoing cell division by binary fission

Question 3

3 major pathways disrupted by antibiotic

Answer 3

1. Cell wall synthesis;
2. Protein synthesis;
3. n.a synthesis

Question 4

Describe the features of peptidoglycan cell wall

Answer 4

High internal osmotic pressure;

Rigid cell wall maintains the shape of bacterium

Question 5

Describe the action of penicillin

Answer 5

Binds to tranpeptidase, inhibiting the formation of cross-links bt adj chains;

Weakens bacterial cell wall of dividing bacterial cells;

Osmotic lysis @ dividing bacterial cells as cell wall synthesis is inhibited;

Question 6

Function of tranpeptidase

Answer 6

Catalyses the formation of cross-links bt peptides that are attached to NAM residues;

-> high tensile strength