Resistant bacteria Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Biology — Foundation

How can antibiotic use make resistant bacteria more common?

The antibiotic kills susceptible bacteria, while resistant bacteria may survive and reproduce, increasing their proportion in the population.

Why does using antibiotics only when essential help limit resistant bacterial populations?

It reduces opportunities for resistant bacteria to be selected and spread.

What is a drug?

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

What are antibiotics?

Drugs used to treat bacterial infections by killing bacteria.

Why are antibiotics ineffective against viral infections?

Antibiotics do not affect viruses.

How does antibiotic resistance affect the treatment of bacterial infections?

It reduces the effectiveness of antibiotics against infections caused by the resistant bacteria.

What is directional selection?

Individuals at one end of a range of variation have greater reproductive success, shifting the distribution of a heritable characteristic over generations.

How can an antibiotic affect resistant and susceptible bacteria differently?

A resistant bacterium may survive and reproduce, while susceptible bacteria are inhibited or killed.

Why can resistant bacteria become a larger proportion of an antibiotic-exposed population?

Surviving resistant bacteria reproduce and pass resistance alleles to their descendants.

Does an antibiotic produce resistance mutations because bacteria need them?

No. The antibiotic selects resistant bacteria; it does not produce a mutation because bacteria need it.

How can a new antibiotic-resistant bacterial strain arise?

A mutation can produce a strain resistant to an antibiotic.

Why can bacterial populations change over many generations in a short time?

Bacteria reproduce rapidly.

How can antibiotic resistance become established in a bacterial strain?

Resistance can be inherited by descendants over generations.

When can a resistant bacterial strain spread particularly readily between people?

When people lack immunity to the strain.

What effect does antibiotic resistance have on treating and limiting the spread of an infection?

It makes the infection harder to treat. Without an effective antibiotic, treatment cannot readily eliminate the infection and limit its spread.

How does reducing unnecessary antibiotic use limit antibiotic resistance?

It reduces opportunities for resistant bacteria to be selected.

When should antibiotics not be prescribed for infections?

For viral infections or for non-serious infections when antibiotics are not needed.

Why should patients complete their prescribed antibiotic course?

The aim is to eliminate the infection so bacteria do not survive and multiply, creating further opportunities for resistant variants to arise and be selected.

Does completing a prescribed antibiotic course guarantee that every bacterium is killed?

No.

How does restricting agricultural antibiotic use help limit resistance?

It reduces bacterial exposure to antibiotics and opportunities for resistant populations to be selected.

Why is it important to preserve the effectiveness of existing antibiotics?

Developing new antibiotics is costly and slow and may not keep pace with the emergence of resistant strains.