Problem 1
What are essential amino acids? How do they differ from non-essential amino acids? Give two examples of each and write their structures.
Problem 2
Explain the classification of amino acids on the basis of their chemical nature.
Problem 3
Give two examples of each of the following, along with their structure: (a) Neutral amino acids (b) Acidic amino acids (c) Basic amino acids (d) Semi-essential amino acids (e) Sulfur containing amino acids (f) \(\alpha\) -imino acids
Problem 4
In general, the natural amino acids exist in which configuration?
Problem 5
What are zwitterions?
Problem 6
Define the isoelectric point of an amino acid?
Problem 7
Write the structural formula for species that exist predominantly for the given amino acids at pH \(1.0\) and 13 respectively. The isoelectric points are: Amino acid Lysine Glutamic acid Isoleucine Alanine Isoelectric point \(9.7\) \(3.2\) \(6.0\) \(6.0\)
Problem 11
What is ninhydrin reagent? How is it used for identification of amino acids? Explain giving chemical equations.
Problem 12
What is a polypeptide linkage? In a polypeptide, what do the terms 'Nterminal' and 'C-terminal' refer to?
Problem 14
What do you understand by N-terminal and C-terminal protection? Write the structure of the species obtained by the reaction of the following amino acids and protective reagents. (a) Valine \(+\) di tert. butyldicarbonate (b) Leucine + benzylchloroformate (c) Alanine + benzyl alcohol
