Antibiotic resistance: selection acts on bacteria
| English | Français |
|---|---|
| strain/streɪn/ | déformation |
| antibiotic resistance/ˌæntɪbaɪˈɒtɪk rɪˈzɪstəns/ | résistance aux antibiotiques |
What would explain this observation?
- It is the bacteria that become resistant to a drug, rather than the patient becoming resistant. Antibiotic exposure changes which bacterial variants survive.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- Mutations produce bacterial variants, some resistant to a particular antibiotic. Susceptible bacteria are killed or inhibited while resistant ones survive and reproduce. Fast reproduction can rapidly increase the resistant strain 菌株’s population, and it can spread between hosts. MRSA is the specification’s example of antibiotic resistance 抗生素耐药性; resistance to one antibiotic does not automatically mean resistance to every possible treatment.
- antibiotic resistance: Ability of a bacterial strain to survive or grow despite a particular antibiotic; strain: A form within a bacterial species with particular inherited features.
Which explanation accounts for increasing resistance frequency?
The specification calls for avoiding inappropriate antibiotic prescribing, including use against viral infections, restricting agricultural antibiotic use and completing prescribed treatment. Current NHS information likewise says to follow the healthcare professional’s directions. New antibiotic development is slow and expensive. The selection explanation must not say bacteria mutate deliberately because treatment was stopped or that every resistant infection has no treatment.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- The specification calls for avoiding inappropriate antibiotic prescribing, including use against viral infections, restricting agricultural antibiotic use and completing prescribed treatment. Current NHS information likewise says to follow the healthcare professional’s directions. New antibiotic development is slow and expensive. The selection explanation must not say bacteria mutate deliberately because treatment was stopped or that every resistant infection has no treatment.
- Analyse supplied before/after counts and distinguish resistant frequency from total bacterial number. Use paper models or prepared data, never culture resistant pathogens. This teaching task does not set treatment length or advise medication changes; the NHS stewardship reference provides the clinical wording alongside the exam specification.
Which two habits make the investigation or model in this case more defensible?
Analyse supplied before/after counts and distinguish resistant frequency from total bacterial number. Use paper models or prepared data, never culture resistant pathogens. This teaching task does not set treatment length or advise medication changes; the NHS stewardship reference provides the clinical wording alongside the exam specification.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: a model has 10 resistant and 90 susceptible bacteria before exposure. Afterwards, 10 resistant and 10 susceptible remain. Resistant number stays 10, but frequency rises from 10% to 50%. This selection event alone changes frequency without requiring a new mutation during exposure. Later reproduction can increase absolute numbers.
Eight resistant and 12 susceptible bacteria remain in a supplied model. Find resistant percentage. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Eight resistant and 12 susceptible bacteria remain in a supplied model. Find resistant percentage.
The result is 40 %. Known: a model has 10 resistant and 90 susceptible bacteria before exposure. Afterwards, 10 resistant and 10 susceptible remain. Resistant number stays 10, but frequency rises from 10% to 50%. This selection event alone changes frequency without requiring a new mutation during exposure. Later reproduction can increase absolute numbers.
Check the conclusion and its limits
- Antibiotics do not treat viral infection. Finishing a prescribed course does not guarantee that every bacterium in every real infection is killed. Mutation supplies variants and selection changes their representation; these processes must not be confused. NHS stewardship reference.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
A patient’s own body becomes the resistant bacterial strain. This claim is false: Antibiotics do not treat viral infection. Finishing a prescribed course does not guarantee that every bacterium in every real infection is killed. Mutation supplies variants and selection changes their representation; these processes must not be confused. NHS stewardship reference.
Antibiotic resistance: selection acts on bacteria: The specification calls for avoiding inappropriate antibiotic prescribing, including use against viral infections, restricting agricultural antibiotic use and completing prescribed treatment. Current NHS information likewise says to follow the healthcare professional’s directions. New antibiotic development is slow and expensive. The selection explanation must not say bacteria mutate deliberately because treatment was stopped or that every resistant infection has no treatment.
A patient’s own body becomes the resistant bacterial strain.
Antibiotics do not treat viral infection. Finishing a prescribed course does not guarantee that every bacterium in every real infection is killed. Mutation supplies variants and selection changes their representation; these processes must not be confused. NHS stewardship reference.
Ability of a bacterial strain to survive or grow despite a particular antibiotic: write the technical term.
antibiotic resistance means Ability of a bacterial strain to survive or grow despite a particular antibiotic.