Using drugs to treat disease.

Lesson objectivesTo describe the difference between

painkillers and antibiotics.To explain that antibiotics only kill bacterial

pathogens.

Describe how you feel when you are ill.

Medicines.

• Some drugs have no effect on the pathogens and just ease the symptoms.

• Remember aspirin just reduces pain it does not stop the cause.

Antibiotics

• These drugs actually target the pathogens.

• People use antiseptics and disinfectants to kill bacteria outside the body but these are far too poisonous.

• They would kill our cells and the pathogen.

Antibiotics

• Antibiotics have really changed how we treat infectious diseases.

• Alexander Fleming studied bacteria wanting to find ways of killing them.

• However, he was a sloppy scientist.

Alexander Fleming

• When he came home from a holiday he notices most of his cultures had mould growing on them.

• However, some had a clear ring around the mould.

• He investigated this and discovered penicillin although he failed to make a stable version.

Ernst Chain and Howard Florey

• They managed to produce penicillin on an industrial scale and saved many lives in the Second World War because of this.

• Antibiotics kill bacteria by damaging the cells without harming our own cells.

• Antibiotics have helped cure diseases such as plague and TB.

Problems

• Antibiotics do not kill viral diseases, and finding drugs that do, has been very difficult.

• Why is this?