What is cholesterol?
Cholesterol is a substance which you make in your liver. It gets carried around you body in your blood. You need it to make the membranes of your body cells, your sex hormones and the hormones that help your body deal with stress. Without cholesterol you wouldn't survive.
Why does the body need it?
To make the membranes of your body cells.
Where is it made?
In your liver
Effects of the 2 types of cholesterol:
*the way your liver works
*the amount of fat in your diet
Saturated fats-increase blood cholesterol level, you find them in animal fats like meat, butter and cheese.
What is the metabolic rate?
It is the rate which the chemical reactions in the body cells take place. It is rate at which your body burns calories, it depends on:
*sex: men have a higher metabolic rate because they have a higher proportion of muscle to fat than women
*exercise: increase you metabolic rate and lack of exercise slows it down
*inherited factors: you metabolic rate can also be effected by the factors you inherit from your parents
*temperature: the warmer it is, the less energy you need. This is because you need to use less energy keeping your body temperature at a steady level. You therefore need to take in less food
Benefits of exercise
*keeps you fit
*builds up muscles - leads to a higher proportion of muscle to fat
*keeps you heart healthy
*lowers your blood cholesterol level
*increases the metabolic rate
Pathogens are microorganisms which causes diseases e.g. Bacteria, viruses and fungi.
How do they make us Ill?
*by damaging our body cells
*by making toxins
Properties of bacteria-
*have no true nucleus but genes in the cytoplasm
*reproduce by dividing into 2 every 20 minutes
*causes diseases like tetanus! tuberculosis! food poisoning, pneumonia
*are killed by antibiotics
*fibre-helps with digestion
*protein-growth and cell repair
*fats-insulation store of energy
*water-keep body hydrated
*vitamin and minerals-good health
*fruit and veg
What is a healthy diet?
Contains all 7 nutrients in the correct amount
What happens when we don't eat healthy?
*obese-heart disease, high blood cholesterol
Properties of virus
-are not true living things - only life process carried out is reproduction
-can only survive and reproduce inside living cells
-are made of a protein coat surrounding a few genes
-are a lot smaller than bacteria
-causes diseases like colds flu, HIV, chicken pix
1. The virus attaches itself to the surface of the host cell
2. The virus injects its genetic material into the host cell
3. The genetic material makes copies of itself
4. New viruses are made with chemicals from the host cell
5. The host cell splits open and dies. The viruses are released
Germs can get into the body through your mouth, nose, cuts, eyes, ears and genital. Germs can spread through the air e.g. Sneezes, cough, through food and drinks.
How do white blood cells fight infections?
White blood cells destroy microbes in 3 ways:
1. White blood cells change their shape to engulf microbes
2 some white blood cells make antibodies to destroy specific bacteria and viruses
3. Some white blood cells make antitoxins to neutralise (render the poisons harmless)
Treatment of disease
-painkillers: drugs which get rid of pain. Do not cure diseases e.g. Paracetamol
-antibiotics: are drugs that kill bacteria inside your cells without destroying cells e.g. Penicillin, do not kill viruses
-Antivirals: are drugs which kill viruses, not man safe and effective Antivirals have been produced. This is because viruses can survive inside our cells. It is therefore difficult to kill viruses withOut kill out cells.
Dr.semmelweiss was a doctor in the 1850's. He put forward the idea to wash your hands. He realised hand washing prevents infections after people were dying.
- over use of antibiotics
- not completeing the cource treatment
- taking antibiotics prescribed for some else
- example: MRSA (superbug) is a bacteria that is resistance to many antibiotics due to natural selection
Bird flu: caused by mutation of viruses leading tonew forms of the disease. This can spread rapidly because no one is immune to it
Epidemic: is the spread of a disease in one country
Pandemic: is the spread of a disease world wide
How does antibiotics resistance arise?
Within a population of bacteria, their might be one that mutates (changes) and is slightly different from the others
Antibiotics kill all but the single odd- bacterium - this is resistant to antibiotics
This bacteria grows rapidly, divides and makes copies identical copies of itself due to having no competition.
There is now a population of bacteria that the antibiotics cannot kill. This forms a new disease e.g. bird flu, swine flu. This process is called natural selection
How do vaccines work?
Vaccines contain a dead or weakened organisms.
The antigens in the vaccine stimulate the white blood cells to produce the right antibodies against the pathogens
In the future the white blood cells will make antibodies quicker.
We say that you are immune to future infections by the pathogens
You need to provide them with:
- Nutrients - provided in a agar jelly (contains carbohydrates as energy source) warmth and oxygen
- Once isolated the plates are incubated at 25*c. This reduces the risk of growing harmful pathogens. In industry plates cultered at higher temperature to speed up growth.
Dr Wakefield published that the MMR vaccine linked to the development of Austism.
children died because they didnthave the vacination