Question

Triglycerides are fatty acid esters of glycerol, which are formed by the esterification of molecule(s) of fatty acids with molecule(s) of glcerol. (a) one, two (b) one, three (c) three, one (d) two, one

Short answer

The correct answer is (c) three, one, as triglycerides are formed from the esterification of one molecule of glycerol with three molecules of fatty acids.

Step-by-step solution

Understanding Triglycerides

Triglycerides are a type of fat found in the blood. They are made from one molecule of glycerol and three molecules of fatty acids. The process of forming triglycerides is known as esterification, where fatty acids bind to the glycerol molecule.

Identifying the Correct Ratio

Since the structure of a triglyceride includes one glycerol molecule and three fatty acid molecules, we need to find the option that correctly represents this ratio.

Selecting the Correct Answer

Based on the known structure of triglycerides, which consists of one glycerol and three fatty acids, option (c) three, one is the correct answer.

Key concepts

Glycerol

Glycerol, sometimes referred to as glycerine, serves as the backbone of triglycerides. It is a three-carbon molecule with hydroxyl (-OH) groups attached to each carbon.

When we consider its structure, glycerol is a simple polyol compound. It's highly soluble in water due to the presence of the hydroxyl groups, which can form hydrogen bonds with water molecules. This aspect of glycerol makes it a valuable ingredient in various pharmaceutical and cosmetic formulations. In the context of triglycerides, these hydroxyl groups are essential as they provide the sites for fatty acid attachment through the process of esterification.

In biology and biochemistry, glycerol's role extends beyond just a component of fats. It also is used as an intermediate in carbohydrate and lipid metabolic pathways, showcasing its importance in biological energy storage and consumption.

Fatty Acids

Fatty acids are long chains of hydrocarbons terminating with a carboxyl group (-COOH). They are key components of various types of lipids, including triglycerides.

The length of a fatty acid's chain and the degree of saturation determine its physical properties. Saturated fatty acids contain no double bonds between carbon atoms, resulting in straight chains that can pack closely together, often leading to solid forms at room temperature. Conversely, unsaturated fatty acids have one or more double bonds causing kinks in the chain, which often results in the substance being liquid at room temperature.

Importance of Fatty Acids

These molecules are not only structural components of fat but also involved in important biological functions such as energy storage, cellular signaling, and acting as precursors to bioactive lipids. They are also integral in establishing cell membrane structure and function, especially impacting fluidity and permeability.

Esterification

Esterification is a chemical reaction in which an alcohol and an acid react to form an ester and water. In the context of triglycerides, this reaction involves the hydroxyl groups of glycerol and the carboxyl groups of fatty acids.

The esterification process for creating triglycerides is a dehydration synthesis reaction, where each ester bond formation releases a molecule of water. This step is crucial for the storage of fats in biological systems as it allows for the compact storage of energy-rich fatty acids, linked to the glycerol backbone.

Biological Significance

Ester bonds in triglycerides are broken down during metabolism to release fatty acids, which can then be converted into energy by the body. This metabolic breakdown is known as hydrolysis, essentially the reverse process of esterification. Understanding this reaction is not only important for biochemistry but is also pivotal in industrial applications such as the production of biofuels and the synthesis of various esters used in fragrances and flavorings.