Antibiotic Resistance 2 Flashcards
How can you tell if an antibiotic is more effective than another
An antibiotic is more effective than another if there is greater clear area.
What happens if an antibiotic is a larger molecule than another
If an antibiotic is larger than another then large molecules diffuse slower through agar so does not reach as many bacteria so clear area of larger molecule is reduced.
Why are antibiotics ineffective against viruses
Antibiotics are 8neffective against bacteria as:
They exist inside cells
Have no cell walls
Viruses use host cell for protein synthesis
How could you measure effects of antibiotic on bacteria
Could measure effects of antibiotic on bacteria by:
Using agar plates and spread bacteria with sterilised equipment (with aseptic techniques)l
Use 5 different concentrations of antibiotic.
Incubation (tape plates closed)
Control :disc alone
Measure clear area
Why is there a need to keep searching for new antibiotics
Need to keep searching for new antibiotics because bacteria develop resistance, enzymes destroy antibiotic and bacteria mutate rapidly.
Why are mammalian cells used to test antibiotic
Mammalian cells are used to test antibiotic to ensure safe use on people as mammalian cells are similar to human cells.
How have bacteria developed resistance to antibiotics
Bacteria have developed resistance to antibiotics because:
Random mutation may result in resistance
Exposure to antibiotic selects resistant mutants which are more likely to survive and reproduce so descendants also have resistance.
Natural selection
Evolve horizontally to share plasmids.
Why does resistance to antibiotics seldom used develop slower
Resistance to antibiotics seldom used develops slower because used less frequently so fewer bacteria exposed so less likely to select resistant mutant.
How can antibiotics counter resistant bacteria
Antibiotics may counter resistant bacteria by preventing bacteria enzyme from working, may block active site so antibiotic not broken down and can act on bacterium.
Why is prescribing antibiotics limited
Prescribing antibiotics is limited because antibiotic acts as a selection pressure and some bacteria become resistant, survive and reproduce so antibiotic is no longer effective.
Also, some infection can’t be treated with antibiotics.
How can experiment be adapted
Experiments can be adapted by changing independent variable and controlling other variables e.g temperature
How can hospitals prevent an increase of resistant strains
Hospitals can prevent increase of resistant strains by:
Putting hand washing regimes
Having Policy for dealing with hospital acquired infections
Improved laundry of bed linen eg higher washing temp
Clothing rules (no ties, watches or long sleeves)
