Introduction to Macromolecules | Main Types with Functions


All the living organisms around us are made up of chemical building blocks composed of biological macromolecules. The macromolecules are large polymers composed of smaller units called monomers. To know more about this broad term macromolecules, let’s read on to find the main types and examples of macromolecules. 

What are Macromolecules?

Macromolecules in biology are the large and complex molecules, formed as a product of smaller molecules like the proteins, lipids, and carbohydrates. The word macromolecules is a polymer, i.e., derived from the Greek word poly (many units). Macromolecules play a primary role in cell structuring and carrying out various functions. 

Types of Macromolecules 

While studying the types of macromolecules, there are four main types classified under the main head. Here is a brief study of each macromolecule in greater detail.


The first type of macromolecule is carbohydrates. These are the sugars and fibers found in food products like fruits, grains, vegetables, and milk products. As per the American Diabetes Association, the carbohydrates are the main source of energy for the body made up of carbon, hydrogen, and oxygen. Being an essential part of the daily nutrients that the body must consume, the intake of carbohydrates should be moderate. According to the National Institutes of Health, on average, a non-diabetic adult must consume 135 grams of calories. 

PS:- Each carbohydrate equals four calories. 

Functions of Carbohydrate

  • Provide energy to the central nervous system and the muscles
  • Enable fat metabolism
  • They influence mood and memory and perform brain functions

Sources of Carbohydrate

The main sources of carbohydrate include leafy green vegetables, bright, sweet potatoes, berries, whole wheat grain, fruits, etc. The lack of a deficiency of this type of macromolecule causes hyperglycemia. 


Lipids are a group of structurally and functionally diverse organic compounds that remain insoluble in the water. This is another type of macromolecules that further classify into fats, phospholipids, and steroids. The lipids are hydrophobic molecules that are formed of both carbon and hydrogen. 

Functions of Lipids

  • Storage of energy, e.g.:- triglycerides
  • Plays hormonal roles such as estrogen and testosterone 
  • Protects internal organs
  • Provide both thermal and electrical insulation

Sources of Lipids

Food High in Unsaturated Fats

soybean oil, canola oil, flaxseed, walnuts, and fatty fish

Foods Rich in Saturated Fat

coconut oil, cocoa butter, and palm oil

Foods With Trans Fat

cookies, frozen pizzas, doughnuts, and other deep-fried fast foods 

Foods Containing Sterols

chicken liver, beef liver, eggs, and chicken


Proteins are large and complex macromolecules that play a major role in regulating the body’s tissues and organs. These types of macromolecules are composed of smaller units called amino acids. 

Functions of Proteins

Here are the functions performed by different types of proteins:-

  • Antibodies bind to viruses and bacterias to protect the body
  • Enzymes carry out various chemical reactions in the cells
  • Proteins bind atoms and smaller molecules together to levitate throughout the body
  • The type of macromolecule a proper structure and support to the cells

Sources of Proteins

The main sources of protein include meat, poultry, fish, eggs, legumes, yogurt, tofu, etc.

Nucleic Acid  

Nucleic acids are another primary macromolecules found in cells and viruses. The two main types of nucleic acids are DNA and RNA. Nucleotides bind up together to form a five-carbon sugar backbone, phosphate group, and a nitrogen base. The chief role played by nucleic acids are regulation and expression of genes. 

DNA includes phosphate-deoxyribose sugar backbone and the nitrogenous base adenine (A), guanine (G), cytosine (C), thymine (T)

RNNA includes ribose sugar and the nitrogenous bases A, G, C, and uracil (U). 

Functions of Nucleic Acid 

  • Store genetic information and enable protein production

Sources of Nucleic Acid

Vegetables. Beans, peas, lentils, spinach, mushrooms, etc


The Complete Information on Macromolecules in a Nutshell 


MacromoleculeBasic Formula, key featuresMonomerExamplesUses
Proteins CHON

−NH2 + −COOH +R group

Amino acidsmeat, poultry, fish, eggs, legumes, and yogurtStorage; Signals; Structural; Defensive; Enzyme; Transport; 
Lipids C:H:O

Greater than 2:1 H:O (carboxyl group)

Fatty acid and glycerolButter, oil, cholesterol, Energy storage; Protection of internal organs; Storage of energy;


MonosaccharidesGlucose, Fructose, Starch, Glycogen, CelluloseEnergy storage; Structure; enable fat metabolism 
Nucleic AcidsCHONP

pentose, nitrogenous base, phosphate

NucleotidesDNA, RNAStores genetic information;


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