Structure and Function of Macromolecules Within a Living Organism

1141 Words Oct 24th, 2010 5 Pages
Structure and function of macromolecules within a living organism ‘Some biological molecules in organisms are small and simple containing only one or a few functional groups, others are large, complex assemblies called macromolecules’ [1].

The term macromolecule is convenient because the bulk properties of a macromolecule differ from those of smaller molecules. These large chemical compounds have a high molecular weight consisting of a number of structural units linked together by covalent bonds, giving them a variety of structures and functions in the body. Macromolecules (also known as supermolecules) are commonly grouped into four major categories: proteins, nucleic acids, lipids and carbohydrates. These are mainly composed of
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A lipid is a substance such as a fat, oil or wax that dissolves in alcohol but not in water. They are easily stored in the body and so serve as a source of fuel. Lipids also come in a compound form when combined with another type of chemical compound, which comprise the lipoproteins, glycolipids and phospholipids.

Phospholipids play an essential role in the cell as they compose the basis for all cellular membranes. They are composite molecules made up of glycerol, fatty acids, and a phosphate group that contains a polar head and two nonpolar tails, forming a protective, yet selectively permeable, fluid outer layer.

Other lipids are used for the capture of light energy (carotinoids), hormones and vitamins (steroids and modified fatty acids), thermal insulation, electrical insulation of nerves and water repellency (waxes and oils).

The Roles of Macromolecules in Biology
The turn of the 20th century saw the start of some major development in the understanding of macromolecules. Although proteins had yet to be crystallised and there was uncertainty about their chemical nature, Emil Fischer had synthesised a protein called octadecapeptide and followed with groundbreaking work on carbohydrates. Concurrently, Pheibus Levine & Walter Jacobs were making headway with their work on the structure of nucleic acids. This development in the understanding of macromolecules lead

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