Criado por Charlotte Hewson
mais de 9 anos atrás
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Questão | Responda |
what is the word antibiotic derived from? | Greek words meaning against life |
what do antibiotics do? | destroy or inhibit the growth of micro-organisms |
what are most produced by? | Bacteria |
what is penicillin made by | fungi |
who discovered penicillin? | Alexander Fleming, 1928 |
how do they work in basic terms? | stop bacteria from making normal cell walls |
how do bacteria cells resist osmosis? | has a cell wall made of inelastic, tough material.as water enters, contents expand and push against cell wall. this halts further entry of water |
what does this prevent? | osmotic lysis |
how do some antibiotics kill bacteria? | prevent the cell wall forming. |
how do they do this? | inhibit synthesis and assembly of important peptide cross-linkages in walls. |
what does this mean for the walls? | they're weakened and experience lysis, killing the bacterium |
when is this type of antibiotic useful? | when the bacteria is growing |
why aren't viruses killed by antibiotics? | they have a different covering from bacteria |
what is resistance due to? | not a change in tolerance but a mutation within the bacteria |
what was the mutation that allowed them to t=resist? | they produced a new protein. an enzyme which broke down antibiotic penicillin before it could kill the bacteria. |
what was the name given to this enzyme? | penicillinase |
how is the production of penicillinase passed on? | vertical gene transmission |
what eventually happens? | this becomes predominant in the population as the frequency for the allele to form penicillinase increases in the population |
how can this resistance be transferred to other bacterial species? | horizontal gene transmission |
what can this lead to? | certain bacteria accumulating DNA that gives them resistance to a range of antibiotics |
what is the name give to these bacteria? | super-bugs |
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