(3.1.4.1) general properties of proteins

Question 1

what is the general structure of an amino acid?

Answer 1

• they all contain an amine group (-NH2) on one end, an carboxyl group (-COOH) on the other, and a single hydrogen
• have a variable R group side chain that they differ by

Question 2

how are dipeptides formed?

Answer 2

• when two amino acids undergo a condensation reaction between the amine group of one amino acid and reacts with the carboxyl group of another
• creates a peptide bond between the two and eliminates a water molecule

Question 3

what are polypeptides?

Answer 3

polymers made up of many amino acid monomers chemically joined together by peptide bonds formed by condensation reactions

Question 4

describe the primary structure of a protein

Answer 4

the primary structure of a protein is the sequence of amino acids in a simple polypeptide chain

Question 5

describe the secondary structure of a protein

Answer 5

• when the primary structure folds and twists
• the folds are called beta-pleaded sheets and the twists are alpha helices; they are held in place by hydrogen bonds

Question 6

describe the tertiary structure of a protein

Answer 6

• secondary structure folds even further into a specific 3D shape
• shape is held in place by bonds between R-groups, including hydrogen bonds, ionic bonds and disulphide bridges.

Question 7

describe the quaternary structure of a protein

Answer 7

formed of more than one polypeptide chain joined together