Question

Please let me know about the clear differences b/w Alkaloid and Fatty acid ??

Answer 1

The main difference is that fatty acids have no nitrogens at all, but alkaloids usually do. Also, alkaloids typically contain rings, but fatty acids usually do not (exception here).

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ALKALOIDS

Alkaloids sounds similar to alkaline, which implies basic.

There are multiple types of alkaloids, so it is usually not sufficient to say "alkaloid", for example, since there are many derivatives (protoalkaloids, polyamine alkaloids, pseudalkaloids, etc).

In general though, for an alkaloid:

• They usually contain many basic nitrogens, but not always (a terpene is an example of a type of alkaloid that does not necessarily contain nitrogen)
• They may or may not derive from amino acids (such as protoalkaloids vs. pseudalkaloids, respectively)
• They may or may not contain a heterocycle as well (ring with multiple types of atoms on it).

Example:

This is Nicotine, a "true alkaloid", which possesses two basic nitrogens, both of which are in a heterocycle, and derives from an amino acid (Proline). Proline looks like this:

You can see that Nicotine has a pyrrolidine derivative in common (cyclopentane with one carbon replaced with nitrogen).

Overall though, alkaloids are distinct from fatty acids in that fatty acids have no nitrogens.

FATTY ACIDS

Fatty acids will contain a carboxylic acid group on one end, and connected to the alpha carbon is a long aliphatic chain, sometimes with double bonds on it, sometimes not. (Aliphatic just means alkyl, whether it has or doesn't have double bonds.)

If there are no double bonds, you have a saturated fatty acid, such as lauric acid. Otherwise, you have an unsaturated fatty acid, such as oleic acid.

Here is an example of a fatty acid: