Proteins are built up of

At the isoelectric point:

What is the $pH$ of $0.01 \ M$ glycine solution? For glycine,$K_{a1} = 4.5 \times 10^{-3}$ and $K_{a2} = 1.7 \times 10^{-10}$ at $298 \ K$.

Which of the following compounds exists as a zwitterion?

Zwitter ion is formed by

Name two $\alpha$-amino acids which form a dipeptide which is $100$ times more sweet than cane sugar?