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p The Role of Protein in Biology Proteins are an important molecule that plays a vital role in living organisms . More than 50 of dry mass of most cells is

protein . Proteins have many different functions and some of them are

Despite having an enormous range of functions , proteins are made up from the same basic components . These are Amino

acids

Proteins are involved in a wide range of jobs in biology , some of which have been mentioned in the above list . Using amino

acids bonds can be made such as

a peptide bond . Also structures can be made by different types of bonds to make

primary /secondary /tertiary /quaternary structures . Each of which have their own shape but they can be made up in so many

different ways by changing the amino acids or replacing one amino acid with another and so on Collagen is probably the most important building block of the animal world as more than a third of the body 's protein is

collagen it makes up 75 of our skin . Collagen acts as a sort of scaffolding for our bodies as it is a structural protein . Collagen

controls cell shape and differentiation and is the reason why bones regenerate and wounds heal

Collagen is a fibrous protein that is found in skin , tendons , cartilage bones and the walls of blood vessels . It is an important

structural protein for not only just us humans but almost all animals Like all proteins collagen is made up of the basic

components of amino acids A collagen molecule consists of three polypeptide chains (it is not an Alpha-helix as it isn 't as tightly wound . The three helical

polypeptides wind round each other to make a three stranded `rope shape . Inside each polypeptide chain there are amino

acids and almost every third amino acid is glycine . This allows the three strands to lie close together because of its small size

The three strands that wind up are held together by hydrogen bonds . Each complete collagen molecule (three stranded

interacts with other collagen molecules which run parallel to it . Bonds form between the R groups of lysine in molecules lying

next to each other . These cross-links made hold many collagen molecules together which are side by side , this forms fibres . The

ends of these parallel molecules are staggered if they weren 't there would be a weak spot running right across the collagen

fibre . Collagen has tremendous tensile strength it needs to be like this as it needs to withstand large pulling forces Protein has a countless amount of jobs and another one is transport . The most obvious transport protein in the human body is

haemoglobin . Haemoglobin , the oxygen carrying pigment which is found in red blood cells , is a globular protein . It is made up

of four polypeptide chains . Two of the four chains make an identical pair and they 're called `Alpha chains . The other two

make another identical pair but are different from the first two pair and...