Antibiotics are a group of chemicals which destroy bacteria They can kill bacteria or stop their growth The agar plate below shows a clear area around antibiotic discs where bacteria have been killed Antibiotics

They are not as specific as antibodies as they may combat a range of bacteria However different antibiotics have differing effects on different bacteria Certain antibiotics will have no effect on some bacteria

An example of Natural Selection It is now a major problem and is making some antibiotics ineffective It has been caused by overuse which has resulted in mutated forms of bacteria (which are resistant) becoming the most common Bacterial Resistance

Many of the resistant bacteria are now called “Superbugs” One very common one is MRSA which has become a serious problem in hospitals Example - MRSA

What is causing the rise in MRSA? Poor hygiene in some hospitals Patients in hospital have weak immune systems Patients in hospital have wounds which could allow the microbes to enter

Hospitals provide an antibiotic rich environment where microbes can come in contact with antibiotics – these kill non- resistant microbes and consequently any survivors are antibiotic resistant

Eradicating MRSA Hygiene – Immediate cleaning of spills – Wearing gloves – All visitors, patients and staff use antiseptic handwashes Patients in hospital have weak immune systems Patients in hospital have wounds which could allow the microbes to enter

Eradicating MRSA More care in using antibiotics Isolating patients with MRSA

The first antibiotic developed was Penicillin A Scottish microbiologist named Alexander Fleming was growing bacteria on agar plates A number had been contaminated with mould (fungus) He noticed that the bacteria did not grow near the mould Discovering Antibiotics

His conclusion was that the mould was producing a substance that stopped the bacteria growing. He called the substance Penicillin since the mould was called Penicillium However he was unable to produce a pure form of the substance In the early 1940’s two scientists called Florey and Chain isolated a pure form of penicillin

Large scale production began but at first penicillin was only available to the military During World War II, penicillin made a major difference in the number of deaths and amputations caused by infected wounds among Allied forces See notes on biodigesters (insulin production) for large scale production of penicillin

Chemicals which people take for other reasons than because they are ill Include – Alcohol – Nicotine (cigarettes) – Recreational drugs (cannabis, cocaine etc) Other Drugs

Why do teens drink so much? Peer pressure Experimentation Trying to escape from problems Alcohol

Harm caused by alcohol Liver damage Foetal damage in pregnancy Societal issues – Violence – Family breakup – Relationship problems – Drink driving – Absenteeism from school or work

Reducing Harm Drinking less each time refraining from bingeing Drinking on fewer occasions Education – knowing limits and units Not drinking and driving Not drinking until 18

Binge drinking Defined as as drinking over double the daily unit guidelines in one session. For men this is over eight units, and for women, over six. However, because individuals are all different, the rate at which they reach intoxication varies.

Binge drinking Binge drinking is a major factor in accidents, violence and anti- social behaviour

Smoking Cigarette smoke contains over 4000 different chemicals However there are 3 main constituents – Nicotine – Tar – Carbon monoxide

Nicotine Addictive Causes irregular heart rate Encourages the body to lay down cholesterol in the coronary arteries (leads to heart disease)

Tar Causes bronchitis (narrowing of the bronchi and bronchioles) Causes emphysema (damage to the alveoli that reduces the surface area) Causes lung cancer (abnormal cell division)

Carbon Monoxide Combines with haemoglobin to reduce the amount of oxygen red blood cells can carry

Illegal Drugs Cannabis Widely used in UK as it is readily available and cheap Causes the user to be relaxed Can lead to taking harder drugs Can also cause mental health problems in some people

Cocaine Causes the user to have a “high” It’s a stimulant Very addictive Effects are short lived and users often need to increase their dose with time An overdose can be fatal