2.1.8 biology- levels of protein structure

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Levels of protein structure:

To make a specific protein, amino acids must be bonded together in s specific sequence. This sequence is determined by the DNA. As the amino acids are bonded, the chain becomes longer. To avoid tangling and breaking, parts of the chain are stabilised by being coiled up or pleated as they are made. The coils and pleats are held in place by numerous hydrogen bonds. The amount of coiling or pleating depends on the types of amino acids being added to the chain, and so depends on the primary structure.

Once the whole chain is complete and the polypeptide is formed, the coils and pleats come together in a specific way to form a specific overall three-dimensional shape. Again, the overall shape is determined by the original sequence of amino acids (R-groups in the primary structure), and is held in place by a number of bonds. The levels of protein structure as follows.

 

Primary structure:

This is the sequence of amino acids that forms the protein.

 Secondary Structure:

The proteins secondary structure is formed when the chain of amino acids coils or folds to form an alpha helix or a beta pleated sheet. Hydrogen bonds hold the coils in place. Although hydrogen bonds are quite weak, many are formed, so overall they give great stability to parts

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