The role of carbohydrates, lipids, water and proteins in living organisms

Carbohydrates are a large group of organic molecules containing the elements of carbon, hydrogen and oxygen. All Carbohydrates are made up of units of  simple sugar molecule called saccharide. Carbohydrates like glucose are broken down during respiration to release energy. Cellulose is a Carbohydrate mainly used in the formation of cell walls.

Lipids are composed of carbon, hydrogen and oxygen elements.  Lipid molecules are made up of glycerol and three fatty acids. Fatty acids and glycerol are bounded together by Ester bonds. Fats are a major source of energy they also act as insulating layer against heat loss. Fats also help form the waterproof cuticle in leaves to reduce water loss. Lipids are part of a structure of a cell surface membrane. 

Water is a solvent that dissolves solutes to make solutions. Water is a good solvent that is why it is a transport medium for many blood molecules. Water aids in removal of metabolic wastes whereby the wastes dissolve in blood plasma to be transported to excretory organs.

Protein molecules contain the chemical elements carbon, hydrogen, oxygen and nitrogen. (CHON). Amino acids are the building blocks of proteins. Amino acids are bounded together by peptide bounds . Proteins are mainly responsible for growth. They help repair damaged tissues and also provide energy in the absence of carbohydrates and fats.