Antibiotics Unit 2 Flashcards
Give 3 ways in which antibiotics can prevent the growth of bacteria.
Prevent cell wall formationcause (cell) lysis inhibit ribosomes inhibit protein synthesis prevent DNA replication affect function of cell membrane
Describe how bacteria can become resistant to antibiotics by vertical gene transmission.
(Plasmid/genes transmitted through) cell division/reproduction/replication/generations
Penicillins are antibiotics. Some bacteria produce an enzyme that breaks down one sort of penicillin.The gene that codes for this enzyme may be passed from one species of bacteria to another species. Describe howSaskia - this question comes up a lot my girl!!
- Horizontal (gene) transmission2. (Gene passed by) conjugation/through pilus
A bacterial infection that cannot be treated with one sort of penicillin can be treated with a different sort. Use your knowledge of enzyme action to explain why the different sort of penicillin is effective in treating the infection (3)
Shape1. Different penicillin has different shape/structure/ enzyme/active site has specific shape/structureBinding2. No longer fits/binds to active site/not complementary to active site/does not form E-S complexConsequence3. (Different) penicillin not broken down;
Farmers often keep large numbers of cattle together. Farmers used to give cattle food which had antibiotics added to it.Suggest how adding antibiotics to the food of the cattle increased profit for the farmers (3)
- Kills pathogenic/harmful bacteria/pathogens2. Disease less likely/improves health/animals healthier/reduces spread of infection3. Faster growth/more productive animals/more food converted to meat/greater survival/lower vet‟s bills/increased yield/less energy (for „fighting infection‟);
Adding antibiotics to the food of cattle is now banned in many countries. Use your knowledge of selection to explain why adding antibiotics was banned.
- (Adding antibiotics) selects in favour of antibiotic resistance/resistant bacteria more likely to survive2. Increase in numbers/higher proportion of resistant bacteria3. May infect humans/may spread resistance to other species/ horizontal transfer
Why is it becoming difficult to treat TB?
some populations of TB bacteria have evolved resistance to the most effective antibiotics, natural selection has led to populations that are resistant to a range of different antibiotics - the populations are multidrug-resistantTo try to combat the emergence of resistance, TB treatment now involves taking a combination of different antibiotics for about 6 months.TB is becoming harder to reat as multidrug-resistant strains are evolving quicker than drug companies can develop new antibiotics
How has bacterial populations evolve antibiotic resistance by natural selection?
1) some individuals in a population have alleles that give them resistance to an antibiotic2) the population is exposed to that antibiotic, killing bacteria without the abntibiotic resistance allele.3)The resistant bacteria surviver reproduce without competition, passing on the allele that gives antibiotic resistance to their offpsring.4) After some time most organisms in the population will carry the antibiotic resistance allele
The number of patients infected with the bacterium MRSA has increased in some hospitals. Scientists have suggested ways to reduce the transmission of MRSA in hospitals. Suggest two ways to reduce the transmission of MRSA in hospitals.
Isolation / quarantine / ‘kept separate’Screening/testing (of patients/doctors etc)Sterilisation of wards/equipment / method to improve hygiene
The minimum inhibitory concentration (MIC) is the lowest concentration of a substance that prevents the growth of a microorganism.When antibiotics are prescribed for treating patients, higher doses than the MIC are recommended. Suggest two reasons why.
May not all be absorbedMay be broken down /metabolised/excreted quicklyTo kill the microorganisms/bacteriaReference to antibiotic resistance
