Biology 1

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B1.1 Keeping Healthy

The effect of food on health.

  • balanced diet and regular exercise is needed to keep the body healthy
  • food is needed for energy

Lifestyle effects disease.

  • If you have a lazy lifestyle you will take longer to fight disease.

Claims made by slimming products.

  • Often they exaggerate how much you will slim with them.
  • usually advised to be used with a "blanaced diet" and "regular exercise". Both things that aong without the slimming product would help you to loose weight.

Our bodies provide an excellent environment for many microbes which can make us ill once they are inside us. Our bodies need to stop microbes getting in and deal with any which do. Vaccination can be used to prevent infection. 

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B1.1.1 Diet and Exercise

  • Carbohydrates
  • Fats 
  • Proteins
  • Minerals/ Vitamins
  • Cereals
  • Dairy
  • Vegetables

Carbohydrates, fats and proteins are sued by the body to release energy and to build up cells. Minerals and vitamin ions are needed in small amounts for healthy functioning of th body.

A person can become malnourished if their diet isn't balanced. This may lead to a person becoming overweight and underweight. An unbalanced diet may also lead to deficiency diseases or conditions such as Type 2 diabetes.

A person looses mass when the energy content of the food taken in is less than the amount of energy expended by the body. Exercise increases the amount of energy expended by the body.

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B1.1.1 Diet and Exercise

The rate at which chemical reactions take place in the body is called the metabolic rate. It varies with the amount of activity you do and the proprtion of muscle to fat in your body. Metabolic rate may also be affacted by inherited factors.

Inherited facors also ffect our health (cholesterol).

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B1.2 How our bodies defend themselves against infe


Hungarian Doctor


Noted that doctors (medical students in particular) were not washing heir hands from looking at dead people with puerperal fever to delivering babies. He noticed that then the mothers began dying of puerperal fever.


Used to treat bacterial infections however can cause bacteria to become immune to antibiotics are only given if competely neccessary. 

Mutations of bacteria and virses

this can cause epidemics and or pandemics because when the bacteria and viruses multiply it can become hugely wdespread. An example of an epidemic is swineflu.

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B1.2 How our bodies defend themselves against infe


Advantages Disadvantages

- Not only you are protected, so are  - Painful

  people who aren't vaccinated 

  because most people are.

- You can fight some fatal diseases


- safer for babies

- body produces white bloodcells and 

  thus antibodies for specific disease


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B1.2 How our bodies defend themselves against infe

Microorganisms that cause disease are called PATHOGENS. 

Bacteria and viruses may produce rapidly inside the body and may produce toxins that make us feel ill. Viruses also damage the cells in which they reproduce as virsues live inside host cells.

White blood cells are split into two groups:

Phagocytes - these ingest the pathogens

Lymphocytes - these produce anti bodies and anti toxins.

The anti bodies then either engulf the pathogen or surround the pathogen and wait for the Phagocytes to engluf it.

The immune system of the body produces specific antibodies to kill a particular pathogen. This leads to immunity from that pathogen. In some cases, dead or inactive pathogens stimulate the bodies antibody production. If a large proportion of the population is immune to a pathogen, he spread of the pathogen is very much redced. 

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B1.2 How our bodies defend themselves against infe

Some medicines such as painkillers do not help your body fight the disease they just relieve the symptoms. 

Antibiotics such as penicllin are medicines that help to cure a bacterial disease by killing infectious bacteria which is inside the body. Antibiotic cannot kill viral pathogens which ive and produce inside host cells.

Specific bacteri should be treated with specific antibiotics. The use of antibiotics ahs greatly reduced the number of deaths from bacterial diseases. However over and inappropriate usage has increased the ate of resistant strains of bacteria.

Many strains of bacteria, including MRSA, have developed resistance through natural selection. 

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