Compare and contrast the four major organic molecules. be sure to include details about their composition, functions, monomers,

All organisms need four types of organic molecules, these are nuclei acids, proteins, carbohydrates and lipids

i) Nucleic acids.
Nuclei acids are ribonucleic acids(RNA) and DeoxyribonucleiC acids (DNA). They are responsible in making proteins that are present in almost every structure and perform every function in the body. DNA exists as a double helix while RNA takes many different shapes, depending on the function. Both are made of backbones consisting of alternating molecules of phosphate and sugar, Nucleotides bases make up the rungs attached to the backbone. 
 
ii) Proteins
They are the most vast among the four molecules making up many structures and carrying out various functions. The building blocks are called amino acids that make up proteins. The amino acids have an almost the same composition but differ in the R group which  gives them uniqueness. May amino acids joined by peptide bonds form proteins.The amino acids also determine the structure and properties of a protein, they are organised to four levels of structure.

iii)Carbohydrates
They consist the largest number of organic molecules, they are sugars, which originate from the process of photosynthesis. Glucose is the simplest sugar, a molecule that is used to provide fuel for many types of organisms. The carbohydrates are classified as monosaccharides (glucose, galactose, etc.), disaccharides and polysaccharides such as starch and cellulose. Monosaccharides are the building blocks of all sugars.

iv) Lipids,
They are mostly known as fats contain the most energy of all the organic compounds. Fats perform many functions in the body e.g phospholipids and the cholesterol which are both components of the cell membrane. They are made up of glycerol backbone and fatty acids, such as triglycerides. One major property of lipids is that they are hydrophobic (insoluble in water)