Biology 1-Health

• Healthy- When you have the correct weight and BMI also if you have no illness
• Factors that influence health: weight, BMI, height, diet

Healthy

• good diet, fitness, hygiene, sleep

Non-Healthy

• drugs, obesity, alcohol

Essential Nutrients

• Carbohydrates- provide energy e.g. glucose
• Fats- Provide energy, act as an energy store and provide insulation
• Proteins- Proteins are needed for growth and repair of tissue, and to provide energy for emergencies
• Vitamins- Various functions e.g. vitamin C  is needed to prevent scurvy
• Minerals- Various functions e.g. iron is needed to make haemoglobin for healthy blood
• Water- We need a constant supply to replace water lost through urinating, breathing and sweating.

Carbohydrates are made up of simple sugars like glucose.

Fats are made up of fatty acids and glycerol.

Proteins are made up of amino acid. Some amino acids can't be made by the body, so you have to get them from your diet- these are called essential amino acids. You can get all the essential amino acids by eating protein that comes from animals, these animal proteins are called 1st class proteins.

Energy and Nutrient Levels Vary

• Age- Children and teenager need more protein for growth. Older people need more calcium to protect again degenerative bone diseases like osteoporosis
• Gender- Females need more iron to replace the iron lost in menstrual blood
• Physical activity- Active people need more protein for muscle development and more carbohydrates for energy

Metabolic Rate- the speed you consume energy at

Obesity

• Obesity is defined as being 20% or more over your recommended body weight
• Caused by too much sugary or fatty foods and too little exercise
• Also caused by underactive thyroid gland
• Obesity can increase the risk of diabetes, arthritis, high blood pressure, coronary heart disease and even forms of cancers e.g. breast cancer

Malnutrition

• Lack of specific types of food or not enough of any sort (starvation)
• Common problems include slow growth, fatigue and poor resistance to infection
• Too little protein can cause kwashiorkor, a symptom is a swollen stomach.

Eating Disorders

• Psychological disorders can cause under-nutrition
• Anorexia Nervosa leads to self-starvations
• Bulimia Nervosa involves bouts of binge eating followed by intentional vomitting
• Can cause liver failure,kidney failure,heart attacks, muscle wastage, low blood pressure etc.

• Drugs- substances that alter the chemical reactions in the body, some drugs are medically useful others are dangerous.
• Drug addiction- you have a physical need for the drug if you don't have it you experience withdrawal symptoms.
• Tolerance develops with some drugs- the body gets used to have it and so you need a higher dose to get the same effect.

Drug Classification

• Class A- heroin, LSD, ecstasy, Cocaine, Amphetamines for injection
• Class B- amphetamines (speed), Cannabis
• Class C- anabolic steroids, tranquillisers

Effect on behaviour

• Many drugs affect your nervous system, they can interfere with the way signals are sent around the body from receptors to the brain and from the brain to muscles.
• Effects of drugs on the nervous system can alter behaviour, e.g. driving isn't safe if you've taken certain drugs
• Drugs also affect judgement, it could mean people taking more risks e.g. sharing needles.
• Drug abuse can also weaken your immune system

Sedatives (or depressants) slow you down, e.g. alcohol. These decrease the activity of the brain, therefore slowing down the responses of the nervous system causing slow reactions.

Stimulants speed you up, e.g. nicotine, ecstasy, caffeine. These do the opposite of depressants- they increase the activity of the brain, making you feel more alert and awake.

1) Computer models are often used in early stages to stimulate human response.

2) Developed further by testing on human tissue. However human tissue can't be used to test drugs that affect whole or multiple body systems.

3) Next, the drug is tested on live animals. The British law states a drug must be tested on two different live mammals.

4)After the drug has been tested on animals, it is tested on human volunteers in a clinical trial- this determines side effects.

Clinical Trials

• Involves two groups of patients.
• One group is given the new drug, the other is given the placebo. A placebo is used so scientists can see the actual difference that the drug makes- it allows for the placebo effect.
• Clinical trials are blind- the patient in the study doesn't know whether they're getting the drug or the placebo, sometimes they're double blind meaning neither the patient nor the scientist knows until the results have been gathered.

Smoking

• Tobacco smoke contains carbon monoxide- this combine irreversibly with haemoglobin in blood cells meaning the blood can carry less oxygen.
• Tobacco smoke also contains carcinogens- chemicals that can lead to cancer.
• Smoking also causes disease of the heart and blood vessels and damage to the lungs.
• The tar in cigarettes damages the cilia in your lungs and windpipe. 
• Nicotine in tobacco causes it to become addictive

Alcohol

• The main effect of alcohol is to reduce the activity of the nervous system-slowing your reactions
• Too much leads to impared judgement, poor balance and coordination, lack of self control, unconsciousness and even coma.
• Alcohol in excess causes dehydration, which can damage brain cells causing a noticeable drop in brain function, and also severe liver damage.
• Dehydration

Pathogens

• Infectious diseases are caused by pathogens, these are microorganisms.
• They include some bacteria, protozoa, fungi and viruses.
• All pathogens are parasites- they live off their host and give nothing in return.
• Microorganisms can reproduce very fast inside a host organism.

Bacteria and Viruses

• Bacteria are very small cells which can reproduce rapidly, they make you feel ill by damaging your cells and producing toxins. Some bacteria are useful if they're in the right place e.g. your digestive system
• Viruses are not cells. They're usually no more than a coat of protein around genetic material. They replicate themselves by invading your cells and using the cell machinery to produce many copies of themselves. Then they cause the cell to break open, releashing new viruses into your body.

• Vitamin deficiency e.g. lack of vitamin C causes scurvy
• Mineral deficiency e.g. a lack of iron leads to anaemia
• Genetic Inheritance e.g. red-green colour blindness
• Body Disorders are caused by body cells not working properly e.g. diabetes and cancer

• Immunisation involves injecting dead or inactive microorganisms. These carry antigens which cause your body to produce antibodies to attack them, even though the microorganism is harmless. If live microorganism then attack then white blood cells can rapidly mass-produce antibodies to kill of the pathogens 

Benefits

• Stops you from getting ill
• We can deal with the illness before it attacks
• Vaccines can slow down or stop the spread of illness

Risks

• Short-term side effects
• If you're already ill you can't have some vaccines
• Some people think immunisation can cause other disorders e.g. a study suggested the MMR jab caused autism

• Genetic counselling is where people are told about genetic disorders or faulty genes that they may carry

Pros

• People can find out if they are carriers of faulty genes in order to ensure their children will be healthy

Cons

• Life insurance may be difficult to get if the insurance company know you suffer from a genetic illness
• Jobs might be harder to get as employers will want healthy people who won't have a lot of days off sick

Gene Therapy means correcting faulty genes- usually a healthy copy of the gene is added

Example- Cystic Fibrosis

• A person with cystic fibrosis has inherited two faulty alleles for a certain gene on one of their chromosomes.
• One method being trialled is the use of a virus to insert a healthy copy of the gene into cells in the airways
• The treatment involves inhaling a fine spray of liposomes into the airways of the lungs. These liposomes will merge with the cells lining the airways.
• However, since this kind of gene therapy involves only body cells (and not reproductive cells) the faulty gene would still be passed on to children.

Problems

• the alleles may not go into every target cell
• the alleles may join with the chromosomes in random places, so they do not work properly
• treated cells may be replaced naturally by the patient's own untreated cells

Food additives are chemicals that are added to food to improve its shelf-life, appearance and flavour

Implications:

• Hyperactivity in children
• allergies
• asthma
• migraines
• cancer

Food Labelling

• Monosaturates and Polyunsaturates are UNSATURATED fats
• Saturated fat- higher cholesterol level

Energy from food which is in excess is stored as fat in the body. People need to consume the right amount of energy in order to keep their weight at an appropriate level. Energy is measured in Kilojoules but most are more familiar with calories.

Apparatus A

• Using test tube, water, thermometer and burning food 
• Lower results as heat lost to surrounding air

Apparatus B

• Using thermometer, copper coil, air filled jacket, water, stirrer
• High results as: stirrer gives even distribution of heat throughout the water, burning of food is more complete because oxygen is fed in, isulation is present which reduces heat loss

Argument For

• Without animal testing, many procedures or new drugs would be extremely unsafe.
• It would be much more inhumane to test drugs on children and adults.
• Take much longer to be tested on humans instead of animals because of life length
• Cheap- animals are easily bred

Argument Against

• Some animals are treated in a cruel and inhumane way.
• Results of some animal testing may not be applicable to humans
• Alternative methods (e.g. computer modelling) can be used
• The cruelty of animals is used for cosmetics such as make up/shampoo
• Some drugs have been withdrawn from the market because of the side-effects

• Smoking has now proven to be dangerous to health (emphysema, cancer etc.)
• Health warning are now on packets
• Number of smokers in this country decreasing overall- people trying to give up (help lines, adverts for smoking patches)
• More young females smoke than young males
• Smoking becoming socially unacceptable (passive smoking)
• More banning of smoking in public places
• Much less advertising/sponsorship
• Minimum age for buying cigarettes
• Nicotine causes addiction
• Asthma

Carbon monoxide combines with the haemoglobin in red blood cells- reduces the ability of the blood to carry oxygen- pressure on circulatory system-can lead to heart disease/strokes

Contains many carcinogens including tar (substances that can cause cancer).

Smoking increases the risk of lung cancer, mouth cancer and throat cancer.

Smoking also covers the mucus in the lungs with tar which makes removal of bacteria from the lungs harder increasing chance of infection

• Genetically (e.g. cystic fibrosis)
• By coming into contact with people/air around them (e.g. chicken pox)
• Food entering the body (e.g. food poisoning)