Biology 1a

Microorganisms that enter the body and cause disease are called Pathogens.

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Diet and Metabolic Rate

You need to have the right balance of foods in your diet, because each food group has a different use.

Carbohydrates release energy

Fats keep you warm and release energy

Protein for growth, cell repair and cell replacement

Fibre to keep everything moving smoothly through your digestive system

Vitamins and Minerals to keep your skin, bones, blood and everything generally healthy

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Metabolic Rate

You need energy to fuel the chemical reactions in the body to keep you alive, they are called your metabolism. Muscle needs more energy than fatty tissue , so people with a higher porportion of muscle to fat in their bodies will have a higher metabolic rate, and people who are generally bigger (taller) will have a higher metabolic rate than smaller people.

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Factors affecting Health

People who have a bad diet (out of balance) are classed as malnourished, they can be fat or thin, or unhealthy in other ways.

Obesity is common in developed countries, defined as being 20% over maximum reccomended body mass.  Health problems as a result of obesity are: high blood pressure, arthritis, type 2 diabetes, heart disease and put you at more risk of some kinds of cancer.

Too much saturated fat can cause high cholestrol.

Too much salt can cause high blood pressure and heart problems. 

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Eating too little

Lack of food is common in developing countries. The effects on malnutrition vary on what foods are missing from the diet. Problems commonly include slow growth, fatigue, poor resistance to infection, irregular periods in women.

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Pathogens

The two main types of Pathogen are: Bacteria and Viruses.

Bacteria are small living cells, they make you feel ill by doing two things. They damage your cells and the produce toxins (poison).

Viruses are not cells and they're smaller than bacteria. They reproduce by invading your cells and produces many copies of themselves. The cell bursts releasing all the new viruses and the cell damage is what make you feel ill.

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Fighting Diseases

Your skin, hairs and mucus stop a lot of microorganisms getting inside your body. Platelets (small fragments of cells) help blood clot quikcly to seal wounds, if there is a low number of platelets it will clot slowly.  The most important part is your white blood cells. They travel in your blood, when there is an ivading microbe they have three ways to destroy it.

1. White blood cells can engulf foreign cells and digest them.

2. Every cell has Antigens on the surface, if your white blood cells come across a foreign antigen is will produce proteins called antibodies which kill the invading cells. If a person is infection with the same Pathogen again, the white blood cells will quickly produce antibodies to kill it, because the person has become immune to it.

3. They produce antitoxins, the counter toxins are produced by the invading bacteria.

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