0610 IGCSE Biology - B15 Drugs
[CORE]
Definition
A drug as any substance taken into the body that _____________ or affects
________________ reactions in the body
Antibiotics
Antibiotics are substances which kill bacteria, but do not
harm other living cells. Most often are made by ___________.
It is thought that the fungi make antibiotics to kill bacteria
living near them - bacteria and fungi are both decomposers,
so they might compete for food.
The first antibiotic to be discovered was ________________.
It is made by the fungus Penicillium, which you might
sometimes see growing on decaying fruit. Many antibiotics kill bacteria by damaging
their ______________. Viruses do not have cell walls, so they are unharmed by
antibiotics. Some bacteria are ____________ to antibiotics which reduces the
effectiveness of antibiotics
[Extended]
The more we use antibiotics, the more selection
pressure we put on bacteria to evolve resistance.
People did not realise this when antibiotics were first
discovered, and used them for all sorts of diseases
where they did not help at all, such as diseases caused
by viruses. Now doctors are much more careful about the
amounts of antibiotics which they prescribe. We should only use antibiotics when they
are really needed - this will help to limit the development of resistant bacteria such as
MRSA (Methicillin-resistant Staphylococcus aureus).
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