1 Block = Amino Acid
2 Blocks = Dipeptide
3+ Blocks = Polypeptide
Polypeptide chain = Protein
The bond which holds the Amino acids together is called a Peptide Bond. Two Amino Acids held together is called a Dipeptide, when there are three or more it is then called a polypeptide and when a polypeptide reaches certain size it is then called a protein.
The body is unable to use protein in the form that it is eaten, so the body will break down the protein into individual Amino Acids then rearrange them into a new order to make the protein needed by the body for growth and repair of tissues. All though the body can make the Amino Acids needed for the body from what is eaten, there are eight which the body must eat in their original form, the body can not make these Amino Acids from protein eaten. These eight Amino Acids are called The eight essential Amino Acids and are classed as first class protein, there are found in animal protein. Therefore if someone is a vegan it is essential that they take a supplement containing these acids otherwise they will become deficient of these acids.
Proteins have to be folded within the body as they are enormous and the body simply wouldn’t have room for them all. There are three levels of folding that takes place:
- Primary structure – This is the sequence of Amino Acids before they are folded.
- Secondary structure – The primary structure is folded into either alpha helix or a beta pleated sheet shape.
- Tertiary structure- The secondary structure is then folded into a globular or fibrous shape depending how the protein prefers to be folded.
There are many functions of protein in the body such as being used for growth and repair of tissues, producing antibodies to defend the body from antigens, enzymes which make biochemical reactions easier and hormones which coordinate certain bodily activities. The average adult requires 48g of protein daily.
Carbohydrates are known as macronutrients and are needed in large amounts daily by the body. They contain the elements:
C Carbon
H Hydrogen
O Oxygen
Carbohydrates are divided into two groups either sugars or starches. Sugars are then divided into Monosaccharides that typical is glucose and Disaccharides which typical known as sucrose which can be added to tea or coffee. These are quick release sugars and are soluble in water, these are the sugars we usually crave. Disaccharides are made from adding together two Monosaccharides in a condensation reaction where water is lost. Starches are known as Polysaccharides, they are typical known as starch, cellulose and glycogen. These are slow release energy carbohydrates and are used for storage.
The simplest form of carbohydrates are Monosaccharides, they are a white crystalline solid, which dissolve in water. Their name is given to them according to how many carbons are present. If they have six carbons they are known as a hexose sugar, if there is five then they are called pentose.
Polysaccharides are insoluble in water, they are a storage carbohydrate that are found in plants. Cellulose are found in plant cell walls and Glycogen are found in animal cells especially the liver and muscle cells.
Carbohydrates are mainly eaten to provide us with energy, we need to eat approx 30g of cellulose polysaccharide, which is our fibre requirement daily.
Sugar is ok for us to eat but should be restricted to small amounts and should always be eaten after a meal. This is because when we eat a meal 20 minutes after finishing we have an acid attack where the natural bacteria in our mouths turns to acid which then attacks the enamel on our teeth this can then lead to tooth decay. It isn’t the amount of sugar we eat that destroys ours teeth but the amount of times which we eat it.
Lipids are classified as either a solid fat or liquid oil. Neither of them can dissolve in water. They provide us with energy for the body, keep us warm and help us float. They contain the elements:
C Carbon
H Hydrogen
O Oxygen
All lipids are made up of two different types of blocks which are :
The most common types of lipids are:
- Triglyceride which contain 3 fatty acids and 1 glycerol
- Phospholipids which contain 2 fatty acids, 1 glycerol & 1 phosphate group
When a fatty acid joins with a glycerol unit it loses water which is called a condensation reaction. The bond between the units is called an Ester bond.
If a lipid contains its full amount of hydrogen’s it is said to be saturated which could be called a bad fatty acid, this can cause a build up in the arteries and then cause a heart attack. If there isn’t the correct amount of hydrogen then it is called an unsaturated fatty acid. The body needs certain fatty acids but is unable to make them itself. These acids are called essential fatty acids. These essential acids can be found in vegetables, seeds and fish. The body only requires small amounts of these acids and are usually present in healthy diets. They play a role in the immune process and vision and also help in the production of hormone like substances.
Cholesterol is a steroid which has lipid like properties. Cholesterol is required to build and maintain . It also forms some hormones such as Oestrogen and Testosterone. The liver produces about 1 gram of cholesterol per day through the bile, which contains cholesterol, excess can cause gall stones.
Diseases such as Anorexia can cause the suffer from losing most of their body fat from starving themselves, this can therefore leave them feeling very cold, which in turn causes their bodies to develop hair all over their bodies which is called Langugo in order to keep them warm.
