Which best describes the contribution of primary (1’) structure of polypeptides to the native conformation of proteins: a) Structure that results from intrachain interactions of amino acid side chains b) Structure that results from interchain interactions of amino acid side chains c) Structure that results from base pairing d)

16.

1) If the pH of the rain drops from 6 to 5 due to air pollution, the rain has become: a) two time more acidic b) four-time more acidic c) ten time more acidic d) one thousand times more acidic 2) which of combination of statement is correct ? the denaturation of protein  1- causes changes in tertiary structure 2- is always an irreversible process 3-has no influence on the solubility 4-occurs only by interaction with heavy metals 5-does not influence covalent bonds and hydrogen bonds select one: a) only 1 is correct b) only 1 and 2 are correct  c) only 3 and 4 are correct d) only 3, 4 and 5 are correct  e) only 1, 2 and 5 are correct

Draw the structure of an α-helix (polypeptide backbone only, no side chains) as accurately as possible (correct number of amino acids per turn, labelled with the correct measurementof the pitch, label each amino acid unit, etc).