Presentation (amino Acid & Protein)

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½ Amino acids are the subunit that make up proteins. ½ Amino acid contain carbon, hydrogen, oxygen, and

nitrogen. ½ It have three important functional group. A. Amino group (-NHΩ) B. Carboxyl acid group (-COOH) C. R group (side chain)

½ khere are four groups of amino acid : non-polar, polar,

basic and acidic. a. non-polar : no electrical charge. : Hydrophobic molecules. b. Polar : R composed of polar molecules and the electrical charge are asymmetrical. : Hydrophilic molecules. c. Basic : Contain basic amino side chain. d. Acidic : consist of additional carboxyl group in the side chain.

½ k o amino acid joined together through condensation ½ ½ ½ ½

reaction. khe process ill produce dipeptide. Breakdo n of peptide bond can be done by hydrolysis reaction. Polypeptide contains hundreds of hundreds of amino acids. khe repeated sequence (-N-C-C-N-)is the polypeptide backbone.

½ A polypeptide chain can fold or coil or become

associated ith other polypeptide chains to form a protein. ½ It is usually refer to four separate levels of organisation, namely: Õ
     
      

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Primary

describe the sequence of amino acids in the protein & usually determines its eventual shape & biological function. Linear sequence of amino acids linked together by peptide bond.

Secondary

the linear structure of protein chain begins to fold/t ist, forming a 3-D spring like structure called Ʉ-helix/Ʌ-pleated sheet. hydrogen bond hold this structure together.

kertiary

once they have been folded by hydrogen bond, polypeptides may then fold into a globular shape hich is maintained by hydrogen bonds, ionic bonds and covalent bonds bet een sulphur atoms in the residual chains of the amino acids.

Quaternary

consist of more than one polypeptide chain. Example, human haemoglobin. Consist of 4 chains rapped around an iron haem group.