BIOLOGY

January - May Revision Set

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  • Created by: Kate
  • Created on: 30-05-11 09:47

Pathogens & Disease

* Infectious diseases are caused by microbes entering & attacking your body.

* Microbes that cause disease are called pathogens.              

  In vaccination, pathogens are shot into the body in a weakened form. This causes the body to produce enough white blood cells to protect itself against the pathogens, while not getting diseased.

* Bacteria (B)  and viruses (V) are the main pathogens.

* Once B and V enter the body, they reproduce rapidly, usually making you ill.  

 * The microbes which cause disease are known as  p_______. Once in the body, they reproduce. They destroy your t_____  and may produce t____ which cause the s______ of disease.


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Bacteria and Viruses

BACTERIA: Single celled living organisms. Smaller than animal & plant cells. Bigger than viruses. Many are harmless and somewhat helpful. We use them to make food like yogurt, make medicine and treat sewage. They often productoxins (poisons) which affect our bodies and make us ill. Sometimes they damage our cells directly. Disease caused by bacteria incclude: food poisoning & cholera.

VIRUSES: V can cause disease in every type of living organism from people to bacteria. Smaller than bacteria. A virus can get inside a cell and, once there, take over and make hundreds of thousands of copies of itself Eventually the virus copies fill the whole host cell and burst it open, completely damaging the cell. The viruses are then passed out in the bloodstream, the airways, or by other routes. Very rarely produce toxins. Diseases caused by viruses include chicken pox, aids and mumps.  

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Inheritance and Health

Inheritance affects:

Mainly your appearance and health - metabolic rate, (Respiration is the chemical reaction that allows cells to release energy from food. The metabolic rate is the speed at which such chemical reactions take place in the body.) the way your liver deals with the fat in your diet & makes the different cholesterols etc. 

Cholesterol: Needed for cell membranes and to make your vital hormones. Two forms carried around blood : one is healthy,= High-density lipoproteins and one can cause health problems = Low-density lipoproteins. If the balance between the two is wrong, your risk of getting heart disease increases.

Eating lots of high fat food results in harmful cholesterol  levels. 1 in every 500 inherit factors which mean they'll have high levels what ever they eat. This is an example of how inheritance affects your health.                          Monounsaturated and polyunsaturated oils - as found in vegetable oils - help to reduce cholesterol levels in the blood, and also increase the proportion of HDLs compared with LDLs.

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Exercise

6213 men were studied. The least active men were 4.5 times more likely to die early than the fittest.

* You are less likely to be overweight if you exercise regularly, partly because  you will be using more energy.

* You will have more muscle tissue, which will increase your metabollic rate. If you can control your weight, you are less likely to be affected by problems such as arthritis, diabetes and high blood pressure.

*Your cholesterol levels are affected by exercise. Regular exercise lowers your blood cholesterol levels. It also helps the balance of the different types of cholesterol. When you exercise, your good cholesterol level goes up and the harmful cholesterol level goes down. This lowers your risk of heart disease and other problems.

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Diet and Energy

CARBS, PROTEINS, FATS, VITAMINS, MINERALS, FIBRE, WATER

If you have an unbalanced diet, you will end up malnourished. Our bodies use carbs, proteins and fats to release the energy you need to live and build new cells. We need small amounts of vitamins and minerals for your body to work healthily. Without them, you will suffer deficiency diseasesOur diet can easily be unbalanced in terms of the amount of energy we take in. too much = over weight. not enough = underweight. 

The amount of energy you need depends on many things:

Males need more energy than a female of the same age, with the exception of pregnant women.

Teenagers need more energy than elders (70's ...)

Your food supplies energy to your muscles as they work. So, the amount of exercise you do affects the amount of energy you need.

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Proportions

The more exercise you do, the more food you need, since you use more energy. The temperature where you live also affects how much energy you need. In warmer countries you need to eat less food, since you use less energy keeping your body temp at a steady level.

Men generally have a higher metabolic rate than women. The proportion of muscle to fat in your body affects your m.rate. Men often have a higher proportion of muscle than women. Exercise and inheritance are the other things that affect your m rate.

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Weight Problems

Obesity:  If you take in more energy than you use, the excess is stored as fat. Obesity can lead to serious health problems such as arthritis, type 2 diabetes, high blood presure and heart disease. Obese people are most likely to die early. 3 Main Ways To Lose Mass:

*cutting back the amount of food you eat. In particular; energy rich foods.

* You can increase amount of energy you use by exercising more.

*DO BOTH! reduce energy & increase exercise.

Exercise: helps you to control your weight. Increase the proportion of muscle to fat. Make your heart healthier.

Lack of food: In some places, people are malnourished because there isn't enough food to eat. Civil wars, droughts and pests can all destroy local crops. Deficiency diseases, due to lack of mineral ions and vitamins, are common in people when they never have enough food.

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