16.Compounds that generate nitrous acid (such as nitrites, nitrates, and nitrosamines) change DNA molecules by:(A)breakage of phosphodiester bonds.(B)deamination of bases.(C)depurination.(D)formation of thymine dimers.(E) transformation of A→T.

7.The isoelectronic point of an amino acid is the point where (A)the pKa of the a-carboxylic acid is the same as the pK, of the a-amino group. (B)the a-carboxylic acid is protonated and the a-amino group is unprotonated. (C)the solubility of the amino acid is maximized. (D)the a-carboxylic acid and the a-amino group are both half protonated.(E)the amino acid carries no net electrical charge.

16.Compounds that generate nitrous acid (such as nitrites, nitrates, and nitrosamines) change DNA molecules by:
(A)breakage of phosphodiester bonds.
(B)deamination of bases.
(C)depurination.
(D)formation of thymine dimers.

(E) transformation of A→T.

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