Published on 17th August 2018

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A compound is made when atoms of different elements join together through chemical bonds. 
This means that compounds will always exist as molecules, not separate atoms. The diagrams show some molecules of common compounds.

Most of the chemicals in the body are compounds. There are two different types of compounds, organic and inorganic. 
Organic Compounds: 
• Contains Carbon and Hydrogen atoms. • The main organic compounds found in the body are:     Carbohydrates, lipids, proteins, nucleic acids, ATP. • They are basically molecules that are associated with living organisms hence ‘organic’. 
Inorganic Compounds: 
• Don’t contain Carbon atoms for example and are not living:       Water, Salts, Metals, Carbon Dioxide, Oxygen. 

Organic Compound Molecules  
Carbohydrates  Carbon / Hydrogen /Oxygen 

There are three main types of carbohydrates:

• Monosaccharides: simple sugars, glucose.
• Disaccharides: fructose, galactose
• Polysaccharides: starches (main carbohydrates found in the body), glycogen (energy reserve stored in the liver and skeletal muscle), cellulose aka fibre is built by plants (we eat this however it cannot be digested so it creates bulk which aids the movement of food through our intestine) 

Lipids (fats and oils)  Carbon / Hydrogen / Oxygen 

Lipids have over double the energy value of carbs and proteins which is easily converted into body fat.  They are composed of glycerol and fatty acids. There are three types of Lipids:
• Triglycerides (neutral fats): the most plentiful fats found in the body and in your diet are solids (fats) or liquids (oils) at room temperature.  They are stored as adipose tissue in the body
• Phosopholipids: those which form an integral part of the cell membrane and also found in high concentration in the nervous system.
• Steriods: also a type of lipid, examples include androgens and cholesterol (the later which can form plaque inside the arteries leading to arteriosclerosis). 

Proteins Carbon / Hydrogen / Oxygen / Nitrogen / Sulphur  Proteins are the most abundant and most important class of molecules in the human body. All body functions require proteins for muscles growth and repaires. Cells are essentially protein factories. Proteins can be seen as building blocks of the body as bone is built from collagen, hair and nails from keratin. They determine cell shape and tissue properties. Almost all cell functions are performed by proteins. The seven major functions of proteins are: • Support: structural proteins
• Movement: contractiles proteins (myosin & actin)
• Transport: transport proteins
• Buffering: regulation of pH
• Metabolic Regulation: enzymes
• Coordination and Control: hormones which regulate the body e.g. insulin & blood glucose levels) • Defence: antibodies protect against invading microbes.
Nucleic Acids Carbon / Hydrogen /  Oxygen / Nitrogen /Phosphorus Nucleic acids are important molecules they are found inside a cell.
There are two types of Nucleic Acids:
• Deoxyribonucleic Acid (DNA) is found inside the nucleus of cells and makes up chromosomes which contain genes.  DNA is the inherent genetic material inside every cell.  It provides instructions for building every protein in the body and it replicates itself before a cell develops ensuring the information inside every body cell is identical.
• Ribonucleic Acid (RNA) is found outside the nucleus and is referred to as the ‘molecular slave’ to DNA.  It carries out the commands of DNA and is used to create specific proteins as per the genetic code. 
Adenosine Triphosphate (ATP) Carbon / Hydrogen / Oxygen / Nitrogen / Phosphorus.  This is the main energy-transferring molecule in the body and provides a form of chemical energy that can be used by all body cells.



These are organic compounds that are needed in small quantities to sustain life. They are essential nutrients that play a crucial role in our body. Because our body cannot produce enough of them on its own, it has to get it from food. Insufficient amounts can cause deficiency and diseases.
They can be divided into two groups:
– Fat-soluble: Vitamins A, D, E & K.
– Water-soluble: Vitamin B complex & C. 

  Function  Found in 
Fat soluble vitamins
Vit A  Building block of the colour pigment in our eyes, antioxidant, helps with procreation, fertility and the development of sex hormones. Tripe, milk and dairy, cheese, fatty fish
Vit D Improves calcium and phosphorus absorption, prevents tooth decay, strengthens bones.  Fatty animal products, herring, salmon, mackerel, fish liver, egg yolk, milk and diary. 
Vit E Antioxidant, protects against free radicals, improves the absorption of vitamine A, boosts immune system, regulates blood pressure.  Many foods, mainly vegetable oils, seeds, nuts, cacao beans, whole grain wheat, avocados and tomatoes.
Vit K  Required for blood coagulation.  Present in all vegetables and leafy vegetables such as broccoli, peas, green cabbage, lettuce, spinach. 
Water soluble vitamins
Vit B complex  helps increase energy levels, lowers risk of heart disease, improves brain & memory function, keeping skin eyes and the nervous system healthy, helping the body release energy from carbohydrate Vegetables, peas, fresh and dried fruit, eggs, wholegrain breads, liver, milk, rice, meat, fish, potatoes, porridge, tomatoes, kidney, broccoli, spinach. 
Vit C Production of collagen, antioxidant, enhances iron absorption, increases production of infectionfighting white blood cells.  Fresh fruit and vegetables, leafy vegetables, cabbage, potatoes, berries, oranges, tangerines, grapefruit and lemon. 
Inorganic Compound
Water  Hydrogen / Oxygen  • The most abundant substance found in the body, it is the ‘universal solvent’ for body fluids (meaning different substances and materials can dissolve in it).
• Water also aids in maintaining our body temperature as it able to absorb and release heat.
• Acts as a lubricant for internal organs, especially when they are in close proximity to bones and tendons, along with creating buoyancy or cushioning (CSF protecting the brain). 
Salts  Sodium Chloride  Salt helps maintain the fluid in our blood cells and is used to transmit information in our nerves and muscles. It is also used in the uptake of certain nutrients from our small intestines. The body cannot make salt and so we are reliant on food to ensure that we get the required intake


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