biology unit 1 summary notes

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Diet, exercise and Health

A healthy diet

we need to eat food for three reasons:

  • For growth and repair

  • For energy

  • To keep us healthy

    Food is made out of five main groups: carbohydrates, fats, proteins, mineral ions, and vitamins.


Why you need to eat it



For energy

Bread, pasta, rice, sugary food


For energy

Butter, cheese, fried food


To build cells and repair tissue

Meat, fish, cheese, nuts

Mineral ions and vitamins

Needed in small amounts to keep the body healthy

Fresh fruit and vegetables

A healthy body is a balanced one with the right amount of foods and energy to match the body’s needs.

A balanced diet- a diet that has the right amount of proteins, fats, carbohydrates, vitamins, minerals, water, and fibre and gives you enough energy.


A person is malnourished if their diet is not balanced. There are two main types of malnourishment:

  • Being underweight- this occurs when people eat too little or exercise too much. Their diet has too little food or energy and they lose body mass.

  • Being overweight- this occurs when people eat too much or exercise too little. Their diet will contain too much food or energy for their needs and the gain body mass.

    The body lacking some food groups, such as vitamins or minerals, can be an effect of malnourishment. This can lead to deficiency diseases, for example, rickets, caused by a lack of vitamin D.


Name of deficiency


Sources of vitamin

Vitamin C


Bleeding and swelling of the gums, loss of teeth, tiredness, muscle and joint pain

Citrus fruits, leafy green veg

Vitamin D


Bone pain

Eggs, oily fish

Vitamin A

Night blindness

Difficult to see in dim light

Dairy products, oily fish



Weak bones and teeth, poor clotting of blood, muscle spasms

Cheese, eggs, milk, green leafy veg



Tired, weak, blood doesn’t transport enough oxygen

Liver, red meat, beans, nuts, dried fruits

Dietary Fibre



Fruit, vegetables, cereal

Metabolic rate

Metabolism- all the chemical reaction going on in cells.

Metabolic rate- the rate at which the chemical reactions in your body occur.

Factors that affect metabolic rate:

  • Exercise – the more you exercise, the more reactions, like respiration, occur in the cells, so the metabolic rate is higher.

  • Proportion of muscle to fat – more muscle and less fat in the body will increase the metabolic rate because reactions occur in the muscle. The more muscle the higher the metabolic rate.

  • Genetic – people inherit factors that will increase their metabolic rate. For example, tall people have a higher metabolic rate.

    Disease and medicine


    Pathogen- microorganism that can cause infectious disease.

    Bacteria and viruses may reproduce rapidly inside the body and may produce poisons, toxins, that make us feel ill.


  • Are much smaller than bacteria

  • When viruses get into our body they need to get into our cells. There they will reproduce rapidly and



I hope this is useful for people taking the biology 1 aqa gcse exam on Tuesday these are my notes, they are slightly different layout to how my original notes were but I really hope it helps people :)

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