Question

Question #2b03f

Answer 1

At pH=1; charge is +1

At pH=7; charge is zero

Explanation:

The amino acid side chains have no pKa values, so the only things that will have charge is Tyr amino group (pka about 9.0) and the Met COOH group (pka about 2.0).
At pH=1, all protons are on, even on the COOH...so the only charge present is on the amino group (+), so the overall charge is +1.

At pH=7, the COOH group is now a COO- (the proton was falling off at pH=2.0, and at 7.0, it is long gone). The amino group proton is still on, so the amino group is +1, the COO- group is -1, and the overall charge is zero.