Which of the following has two aminogroups in the side chain -
Ans is 'b' i.e., Arginine* Aminoacids have an aminogroup and carboxyl group as functional groups. Apart from these functional groups, they also have a side chain.* Aminoacids are classified based on the side chain asa) Polar aminoacidsb) Non polar aminoacids* Polar aminoacids are aminoacids which are soluble in polar solvents like water. For them to be soluble in polar solvents like water, they should be either charged or they should have polar groups like -OH or -SH or -NH groups, which can form hydrogen bonding with water.* Hence polar aminaocids are classified as# Charged and# Uncharged* Charged polar aminoacids are classified as# Positively charged or basic aminoacids* Histidine, Lysine and arginine* These aminoacids have additional aminogroups in the side chain (other than the functional aminogroup)* Histidine has two iminogroups* Lysine has one aminogroup* Arginine has two aminogroups# Negatively charged or acidic aminoacids* Aspartic acid and Glutamic acid* These aminoacids have additional carboxyl groups in the side chain (other than the functional carboxyl groups)* Uncharged polar amino acids are classified as# Hydroxyl group containing aminoacids* Serine, threonine, tyrosine# Sulphydryl group containing aminoacids* Cysteine* Aminogroup containing aminoacids# Asparagine and Glutamine# These aminoacids have only one additional aminogroup in the side chain* Non Polar aminoacids are classified as:Aliphatic aminoacids# Glycine, Alanine, Valine, Leucine, isoleucine and Methionine# Out of these Valine, Leucine and Isoleucine are branched chain aminoacidsAromatic aminoacids# Phenylalanine and Tryptophan (Though tyrosine is aromatic, it is polar but uncharged, because it has a hydroxyl group).Iminoacid# Proline
Glycine
Arginine
Lysine
Asparagine
Proteins and Amino Acids