Chapter 23.3, Problem 13SSC

Interpretation Introduction

Interpretation:

The structures of fatty acids, triglycerides, phospholipids and steroids should be described.

Concept introduction:

The molecules which contains hydrocarbons and not soluble in water but soluble in nonpolar solvents is known as lipid.

Lipids are classified as:

Triglycerides, Phospholipids and, Steroids and Waxes

Explanation of Solution

The building blocks of fat in our bodies and in food are known as fatty acids. Fatty acid consists of carboxylic acid with long aliphatic chain which can be saturated or unsaturated. Generally, fatty acids exist as: phospholipids, triglycerides and cholesteryl esters. These are important structural components for cells.

The type of lipid found in our blood is known as triglycerides. Triglyceride is obtained by the three glycerol molecules and three fatty acids. Fats and oils consist of molecules known as triglycerides (contain ester bonds).

In structure of triglyceride, three glycerol molecules and three fatty acids linked with each other by ester bonds.

Structure of triglyceride is:

General structure of phospholipids contains a glycerol molecule(s), phosphate group and two fatty acids. The type of lipid which is the main component of cell membrane is known as phospholipid. Phospholipid consists of two fatty acids and a phosphate group.

In the structure of Phospholipid, two fatty acids and a phosphate group linked with each other by ester bonds.

General structure of steroid contains 17 carbon atoms which are linked with each other in four fused rings, three rings contains six carbon atoms that is cyclohexane rings and one is five membered ring that is cyclopentane.

The four ring structure of steroid is: