Question

Give 2 examples of saturated fatty acids and answer each of the following aspects:

1. Describe chemical characteristics and graph the structure of the two
2. What is the function in the organism of the two examples
3. Classify and explain if it is Saponifiable or non-saponifiable from the two examples

Answer 1

In general fatty acids have long hydrocarbon chains with a carboxylic acid at the end. Saturated fatty acids do not have double bond between their carbon atoms (C-C). But unsaturated fatty acids have double bonds in their carbon atoms (C=C).

Palmitic acid (16C) and Arachidonic acid (20C) are the examples of saturated fatty acids.

# Palmitic acids are backbones of triglycerides. They are the most stored form of fatty acids. When there is shortage of glucose, these molecules will be taken to fulfill the energy need. Palmitic acids found in the majority of organisms. It accounts for almost 30% of our body fat.

# Arachidonic acids are the precursor for prostaglandins and eicosanoids. Prostaglandins and eicosanoids play a very important role in immune related functions. Arachidonic acids act as a precursor for phospholipids which are the integral part of plasma membrane.

# Saponifiable lipids will be easily hydrolysed by NaOH and those generally have ester linkages. Both the fatty acids mentioned above can form ester bonds with glycerol. This bonds form inbetween acid of fatty acid alcohol of glycerol. So both of them can form soap when they are treated with sodium hydroxide and they are saponifieable. Examples for no-saponifieable fat are cholestrol and prostaglandins.