INTRODUCTION

1. INTRODUCTION TO MACROMOLECULES

This module introduces the pupils to the major macromolecules of life such as carbohydrates, lipids, proteins and nucleic acid. This biomolecules plays crucial role in cellular functions and processes within living organisms..

Macromolecules are large, complex molecules formed by the polymerization of smaller subunits (monomers). They have high molecular weights and complex 3D structures.

This module introduces the pupils to the major macromolecules of life such as carbohydrates, lipids, proteins and nucleic acid. This biomolecules plays crucial role in cellular functions and processes within living organisms.. 

1.1. Formation of Macromolecules

HOW ARE MACROMOLECULES FORMED?

1.2. Carbohydrates

 Carbohydrates are biomolecules, found abundantly in living organisms. 

They contain more than one hydroxyl group (-OH) In addition to aldehyde (COH) or ketone group (C=O). Thus, they form in to polyhydroxy aldoses or polyhydroxy ketoses. 

Carbohydrates can be classified inTo 

Monosaccharide : Mono is the smallest sugar unit. For example glucose

Disaccharide: is made up of two monosaccharides joined by glycosidic linkages. for example Sucrose

Polysaccharides: example is cellulose

Composition: carbohydrate molecule contain Carbon, hydrogen, and oxygen (1:2:1 ratio).

Functions:

•       Energy source (e.g., glucose in respiration).

•       Structural components (e.g., cellulose).

•       Energy storage (e.g., glycogen, starch).

1.3. Protein

Living systems are made up of Proteins which are the dehydration polymers of amino acids.

Composition: Carbon, hydrogen, oxygen, nitrogen, and sometimes sulphur.

 Each amino acid residue is joined by a peptide linkage to form proteins. 

Proteins are the molecular instruments in which genetic information is expressed, Hormones, Antibodies, transporters, the lens protein, the architectural framework of our tissues and a myriad of substances having distinct biological activities are derived. 

The type, nature and number of amino acids impart characteristic properties to the proteins. 

 There are about 300 amino acids, but only 20 are coded by DNA of higher organisms. 

The structural organization of proteins could be primary, secondary, tertiary and quaternary. 

The three dimensional structure is the most biologically active one. In addition, the unfolding and disorganization of the proteins results in denaturation, the process is mostly irreversible. Such a protein may lose its biological function. 

1.4. Lipid

Lipids are organic compounds that contain hydrogen, carbon, and oxygen atoms, which form the framework for the structure and function of living cells.

These are organic compounds and nonpolar molecules, which are soluble only in nonpolar solvents and insoluble in water because water is a polar molecule. 

In the human body, these molecules can be synthesized in the liver and are found in oil, butter, whole milk, cheese, fried foods and also in some red meats.

1.5. Nucleic acid

Nucleic acids are the large macromolecules in the cells which are very long linear polymers, called polynucleotides.

They composed of nucleotides 

A nucleotide contains:  five-carbon sugar molecules

One or more phosphate groups

A nitrogenous base 

DNA: A, T, G, C  

RNA: A, U, G,C