Friday, July 13, 2012

STPM Biology - chapter 1: Reision essay question 26


26. Describe briefly the primary, secondary and tertiary structure of proteins. State the important of these structures which are related to the properties of proteins. [11]

Answer:

A)   Primary structure:
-sequences of amino acid in the polypeptide chain.
-polypeptide chain consists of amino/N-terminal and carboxyl/-terminal.
-numbering of sequence starts from N-terminal.
-the amino acids are linked by peptide bonds
-total amino acid/R-group/ side-chain/functional group determine protein to be basic, acidic or neutral/ soluble/ insoluble.
Secondary Structure:
-depends on hydrogen bonds.
-Produces α-helix and β-pleated structure.
-α-helix gives high elasticity/ cylindrical structure/ coiled in the helical structure.
-β-pleated is for padding and cushion.
-both structures may be present in a protein.
Tertiary Structure:
-depends on disulphide bridge/ bonds.
-hydrophobic interaction/ bond, ionic bond and Van der Waals effect.
-forming globular structure gives/ determines biological activity
destroyed.

Assignment submitted by L.E., Teh, E. L., Wong,Tan Findy

2011/2012 (IBM)






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