Proteins are made up of amino acids. The amino acids are in different sequences in each protein, making them unique. Rather than being a straight chain, proteins fold into distinctive shapes. Their shape determines their function in a cell or organism. It is like those children’s toys where different shapes fit into their corresponding hole. Only circular pieces fit into circular holes. However if one of those circular pieces could be reshaped into a triangle, it wouldn’t fit into the circular hole and the toy wouldn’t function. It is the same with proteins. If one changes its shape then it can no longer function the way it should.

     Proteins, which are chains of amino acids, are known to fold to form a number of shapes. Some take the form of a helix while others are shaped into pleated sheets. In some proteins sections will form helices while other parts of the same protein can form pleated sheets (see Fig. 2).