antibiotics 3.1.8

• there are two main types of drug, one only relieves the symptoms and one treats the cause and cures the illness
• antibiotics kill bacteria
• antibiotics prevent the bacterias cell wall from forming correctly, so the cells can explode if they absorb water
• antibiotics are naturally produced by fungi to reduce competition from bacteria when there is a shortage of food
• however, some bacteria develop resistance to antibiotics by mutating
• bacteria can be grown on an agar plate and different antibiotics can be tested to determine which is the most effective
• to calculate the zone of inhibition - where bacteria has been killed or prevented from growing, find the diameter and divide by 2 then use the area of a circle: pi r ^2
• advantages of antibiotics are they treat bacterial viruses that killed millions in the past and they can kill a wide range of bacteria
• the disadvantages of antibiotics are they can harm the wrong kind of bacteria, they have no effect on disease caused by viruses, they are difficult to develop, some people can be allergic and some strains of bacteria have become resistant
• it has been more difficult to develop medicines against viruses than it has for antibiotics because viruses reproduce inside the cells of the body and so it is hard to develop drugs without harming the cells and tissues