Question

Justify the placement of the different amino acids in their respective classes. Also, what is special about each class of amino acids (eg. acidic, aromatic, etc.)?

Answer 1

there are two major groups of amino acids, hydrophobic and hydrophilic. these two groups are then subdivided into groups such as acidic, basic, neutral, etc.

Explanation:

please take a look below on the picture showing classification of amino acids(aa)

Hydrophilic group

group which has electrically charged side chain have amino acids having the capability to either donate or accept, a hydrogen ion (`H^+`) or a pair of electron. So, whenever they accept or donate hydrogen ion or pair of electron they become electrically charged.

1. AA which have Nitrogen in their side chain are basic aa. These aa are very good `H^+` or electron pair acceptor but as it accepts charged particle it imparts a positive charge to the aa.

2. AA which have Carboxylic group (`-COOH`) in their side chain are acidic aa which can easily donate `H^+` ions to other and leaving a negative charge on itself.

3. The group with Polar aa are uncharged yet hydrophilic aa as they have an alcohol (`-OH`) functional group in their side chain, being a polar functional group they interact with water molecules as water is also polar.

Hydrophobic group

The non-polar group is characterised by its alkyl group in the side chain. the alkyl group is either an aromatic ring or a simple hydrocarbon chain.

1. AA which have aromatic group (benzene group) in their side chain are aromatic aa. remeber proline is not an aromatic aa as it has unique structure where the aliphatic chain is forming bond with the amino group of aa

2. AA which have alkyl group in their side chain are aliphatic aa. there are some special aa which have Sulphur/sulfur in the side chain but they are still non polar.

to sum up what I have discussed the video below explains it with interactive animationclassification of amino acids