Which of the following acids behaves like a salt in aqueous solution?

The number of peptide bonds in the compound is:

The prosthetic group of haemoglobin is

Which among the following is a globular protein?

Which of the following amino acids contains an alcohol functional group?

The structure of a peptide is given below. If the absolute values of the net charge of the peptide at $pH = 2$,$pH = 6$,and $pH = 11$ are $|z_1|$,$|z_2|$,and $|z_3|$,respectively,then what is $|z_1| + |z_2| + |z_3|$?