9700/12 Biology Oct Nov 2021 Online Test | Cambridge AS and A Level MCQ

What occurs during protein denaturation by extremes of pH?
1 breakage of peptide bonds leading to loss of shape of active site
2 disruption of existing ionic bonds between amino acid R-groups
3 loss of $\alpha $-helical regular arrangement of amino acids
4 loss of protein tertiary structure resulting in loss of function