BRAINCAKEAntibiotic Resistance
Antibiotic resistance means that an antibiotic no longer kills or inhibits the growth of a bacterium at the doses normally used.
How resistance arises. Resistance starts with a random mutation in bacterial DNA. Mutations are not caused by the antibiotic; they occur by chance, for example as errors in DNA replication. Because bacteria divide so often and populations are huge, resistant mutants appear quite frequently.
Mechanisms of resistance. A resistance gene can protect a bacterium in several ways:
• making an enzyme that breaks down the antibiotic, such as β-lactamase (penicillinase), which breaks the β-lactam ring of penicillin;
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Key terms in this lesson
- plasmid
- A small, circular piece of DNA, separate from the main bacterial chromosome, that can be transferred between bacteria and often carries genes such as antibiotic resistance.
More in Bacteria and Disease
- Protein synthesis Inhibitors
- Cell Wall Agents
- Cell Membrane Agents
- DNA Gyrase Inhibitors
- Creating Drug-Resistant Bacteria
- MRSA
- Clostridium difficile
- Prevention and Control of Infection
All 30 lessons in Bacteria and Disease · All Edexcel A-level Biology topics