Friday, July 13, 2012

STPM Biology - chapter 1: Reision essay question 16


16. Describe briefly the primary,secondary ,and tertiary structures of proteins.State the importance of  these structure which are related to the properties of protein.

Answer:

The Primary structure of protein refers to the linear sequence of amino acids in a polypeptide chain.The amino acids are linked by peptide bonds .The polypeptides chain consists of an amino and a carboxyl terminal .The R-group determines the properties of the protein .The sequence of amino acids dictates the biological function of protein.The secondary structure of protein refers to a way particular linear polypeptide chain is coiled or pleated .It is dependent on the availability of specific R-groups of the amino acids to form hydrogen bonds in the protein , to produce an α-helix or β-pleated structure.The α-helix structure provides elasticity to protein. The β-pleated structure is highly resistant to stretching .The tertiary structure of protein refers to the three-dimensional ,compact and globular shape polypeptide . The arises when a polypeptide chain bends and folds extensively.The tertiary structure is maintained by the interaction of hydrogen bonds ,ionic bonds, disulphide bridges and hydrophobic interactions .A protein denatures when its tertiary structure is destroyed .

Assignment submitted by C.Y., Tan, B.X., Loh, J.E., Tai, W.L., Kwan, G.H., Tan  2011/2012 (IBM)


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