Question

draw the general chemical structures of the following class of lipids. show the chemical structure of the backbone explicity in each cases.

1.Fatty acids

2.Wax

3.Triglycerols

4.Glycerophospholipid

Answer 1

1. Fatty Acids

Fatty acids consist of a carboxylic acid (C-O-OH functional group) with a long un-branched hydrocarbon chain. They serve as a precursor for other lipds and are used by the body for energy storage. Fatty acids always have an even number of carbons, which is most commonly 12 or 20. They can be divided into two categories: saturated or unsaturated. Saturated fatty acids have single bonds between each carbon. Dietary saturated acids are abundant in animal products such as cheese, butter, and meat. An example is lauric acid (found in coconut milk), whose structure is shown below:

2. Waxes

Waxes are a class of simple lipids that are esters derived from a fatty acid and a long-chain alcohol. In general, their chemical structure consists of two hydrocarbon chains on either side of an ester group:

Biologically, waxes are used by both plants and animals for protection and water-repellence. For example, waxes coat the leaves of many plants in order to minimize water evaporation. They also coat the feathers of birds to minimize wetting. Beeswax produced by bees to create the structure of honeycomb cells. It includes wax called myricyl cerotate, whose structures are shown below as an example:

3. Triglycerides

Triglycerides, also known as triacylglycerols, are fatty acid triesters of glycerol, consisting of a glycerol molecule attached to three fatty acid "tails". They are the most common form of lipids and can be labeled as a fat if solid at room temperature and an oil if liquid. The synthesis of triglycerides is shown below as an example of their structure:

4. Phospholipids

Phospholipids are the second most common group of natural lipids. They are the main structural lipid group, as they form the major component of biological membranes. Other cell membrane lipids include a related group, sphingolipids, and cholesterol. Phospholipids are formed from glycerol esterfied with two fatty acids (a diglyceride) and one phosphate group. The general structure of phospholipids features a hydrophilic phosphate head attached to the hydrophobic fatty acid, as illustrated below :