The isoelectric point of alanine is $pH = 6$. At which $pH$ will the maximum concentration of the zwitterion of alanine be present?

Nitrogen is an essential constituent of which of the following?

The total number of amino acids present in insulin is

Choose the correct Zwitter ionic form for aspartic acid.

Assertion $(A)$: In aqueous solution,amino acids exist in dipolar ion form.
Reason $(R)$: Most of the naturally occurring amino acids have $L$-configuration.
The correct option among the following is:

What is the total number of essential amino acids?