common macromolecules

Functions of Common Macromolecules


The macromolecules in your body perform a variety of functions. The four major classes of biological macromolecules are carbohydrates, lipids, proteins, and nucleic acids. These molecules all have unique functions that make them essential for life.

In this post, we will discuss the building blocks and the critical functions of these macromolecules: Carbohydrates (sugars), Proteins (amino acids), Nucleic Acids (nucleotides), and Lipids/Fats (lipoproteins). In case you wish to skip this guide, our professional biology writers for hire are ready to cover you by acing that assignment for you.

The Main Types of Biological Macromolecules

Below are the four main types of biological macromolecules, their structures, and their functions.


Carbohydrates are organic compounds that contain carbon, hydrogen, and oxygen. Humans use these biological molecules for energy storage in the form of glycogen. The sugars that form carbohydrates are broken down to release energy in a process called glycolysis.


Image: Chemical structures of carbohydrates

The building blocks of carbohydrates are sugar molecules made up of six carbon atoms and 12 hydrogens. The most common form is a molecule called glucose. Glucose is a monosaccharide, which means it has only one sugar molecule.


Carbohydrates can be broken down into two types: Monosaccharides and Disaccharides

  • Monosaccharides: molecules that contain one sugar molecule or monomer. Examples are glucose, fructose, and galactose.
  • Disaccharides: molecules containing two sugar molecules or monomers joined together through a glycosidic linkage bond. The two most common types of disaccharides are sucrose (table sugar) and lactose (milk).
  • The carbohydrate group also includes polysaccharides, which is a molecule that has many monomers or sugar molecules. Starch and glycogen are examples of carbohydrates that are polysaccharides.


The functions of carbohydrates include providing a source of energy for the body and aiding in fat storage.

When glucose is broken down, they release its stored energy to make ATP (Adenosine Tri-Phosphate). ATP is a molecule that cells use as their primary energy source.

Carbohydrates are also vital for the proper function of many organs, including your kidneys and brain.

They also act as a source of fibre, which can help prevent constipation and certain types of cancer.

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These biological macromolecules are made up of amino acids. Proteins are involved in various bodily processes, including repairing and maintaining cells, hormones, and antibodies.


Image: The 4 levels of the protein structure

Proteins are made up of amino acids that form a chain in the shape of a zig-zag. There are 20 different types of these building blocks, which combine to create different proteins.

The amino acids are linked together by a peptide bond. The joining bond is an amide linkage between the carboxyl group of one amino acid and the nitrogen atom on another amino acid.

The order of the amino acids and their shape and folding determines what function it has in your body.

Examples of proteins are:

Collagen, is found in connective tissue and helps regulate blood clotting. Another example of a protein is hemoglobin, which carries oxygen to your cells.

Functions of Proteins

Image: Examples of proteins in the body

Proteins are involved in a variety of bodily processes, and they perform a wide array of functions. Below are some of the functions of proteins in living organisms:

  • They repair and maintain cells, hormones, and antibodies.
  • Enzymes speed up chemical reactions in the body by lowering their activation energy.
  • Proteins are also a major building block of muscle and tissue, which helps with your growth, strength, and repair process.
  • Hemoglobin carries oxygen from the heart to the rest of the body
  • The hormones thyroxine and insulin coordinate various activities in living things
  • Myosin is a protein that helps living things contract muscles
  • Protein immunoglobulins act as a defence mechanism against harmful foreign elements like viruses.

Nucleic Acids

Nucleic acids are made up of monomers called nucleotides. The building blocks are either purine or pyrimidine, which are nitrogen-containing molecules. The two main nucleic acids are DNA and RNA.


Image: Nucleic acids structures

A nucleotide is the simplest form of these macromolecules. It consists of a phosphate group, a five-carbon sugar (either ribose or deoxyribose), and one of the two nitrogen-containing molecules.

Nucleic acids are found in cells, and they are the molecule that communicates information from DNA to RNA, which translates this information into proteins for body processes.

You may be interested in checking our guide on the Extracellular Matrix Function (ECM), to expand your knowledge of proteins

Functions of Nucleic Acids

  • DNA- It stores the genetic information that is passed down from parents to their offspring.
  • RNA- It is similar to DNA. It is found in cells and also can be used for protein production.
  • There are three types of RNA found in cells:
  • The mRNA (messenger RNA) is used to translate the DNA’s genetic information into proteins. It does this by combining with ribosomes.
  • The tRNA (transfer RNA) is used to put together amino acids into proteins, and it also helps with the production of neurotransmitters, proteins, and hormones.
  • The rRNA (ribosomal RNA) is found in the ribosomes of cells involved in protein production.
  • Nucleic acids also help regulate the cell cycle, which is essential for cellular growth.
  • The nucleic acid contains all of the genetic information that can then be transmitted from parent to the offspring.

Lipids and Fats

These are biological macromolecules consisting of fatty acids. These molecules can be found in your cells, as well as other parts of the body.

Structure of Lipids and Fats

Image: Lipid structure

The building blocks of lipids and fats are fatty acids. The names for these molecules in the two types of macromolecules come from their structure.

In lipids, the fatty acids are linked by ester bonds, and in fats, they’re joined with glycerol molecules through ester bonds.


The two types of lipids are:

  • Triglycerides, consist of three fatty acids linked together by ester bonds to a glycerol molecule.
  • Phospholipids are made up of two fatty acids and one phosphate group connected by ester bonds to a glycerol molecule.

Functions of Lipids and Fats

Image: Lipid layers

The lipid performs a wide array of functions in the body

  • They protect and cushion body organs and tissues.
  • They produce energy to fuel cells, which can be used to keep you going.
  • Lipids and fats also play a role in producing hormones, neurotransmitters, and other important body processes.
  • Fats serve as a reserve of energy and help with the absorption, storage, and release of fat-soluble vitamins.
  • Lipids are a major component in the cell membrane, and they make up the plaques that form on your arteries, leading to a coronary heart attack.
  • Fats and lipids insulate your body to keep it warm and are also present in the myelin sheath around your nerves.
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Process Examples of The Main Macromolecules’ Functions

The following are some of the functional processes of proteins, lipids, carbohydrates, and nucleic acids(DNA and RNA).

Proteins(enzymes) as Catalysts

Enzymes are a type of catalyst that can help with digestion, break down molecules for use as fuel, or make other substances.

Enzymes also break down alcohol before the body eliminates it. They can also help with breaking down foods into sugars for use in cellular respiration.

During a chemical reaction, the catalyst speeds up the process but remains unchanged at the end.

In some cases, an enzyme can combine with a substrate to create a more stable product. In other cases, the substrate may be a waste product that is eliminated from the body.

For example, an enzyme in your stomach called pepsin helps break down proteins into amino acids. The substrate is the protein, and it produces a more stable product, namely a peptide.

Lipids Cushioning Major Organs

Lipids also have a significant role in the heart, liver, and kidneys because they form cushions around these organs to protect them.

A triple layer of lipids cushions the heart, the liver has up to five layers, and four or five layers protect the kidneys.

An example of how lipids protect the heart is that fats are so soft and gooey, that they can fill in any crevices. When heart cells are damaged, the lipids can close up any cracks and fill in gaps to prevent further damage.

Carbohydrates Producing Energy

Carbohydrates are the primary source of energy for our bodies. They first need to be broken down into glucose and then converted into energy. Animals break down carbohydrates into glucose by chewing and digesting them. The body then releases insulin to help transport the sugar from the bloodstream to cells.

Carbohydrates are then broken down into glucose and finally converted to energy. This process is done primarily by the liver, muscles, or brain cells. After the conversion, glucose is stored as glycogen for later use or released into the bloodstream, providing fuel to other body cells.

Nucleic Acids Transferring Genetic Materials

Image: gene replication

Nucleic acids are chains of nucleotides that form genes and chromosomes. They transmit genetic materials from parent to offspring during reproduction. There are three types of nucleic acids: DNA, RNA, and mRNA.

DNA is a double-stranded helix consisting of deoxyribonucleotides. DNA is found in the nucleus of cells and holds genes that determine an individual’s characteristics, such as eye colour or blood type.

RNA is a single-stranded molecule that has genes but does not hold them. It links DNA to the cell’s protein factories or ribosomes. The mRNA is the molecule that encodes genes and sends them to the cell’s protein factories, or ribosomes.

DNA is a nucleic acid that contains genes. Cells in the body are constantly replicating, and genes transfer from mother to child during reproduction.

The genes from the mother are copied into a new cell, but only half of them will be passed on to the daughter cells. The genes are split during replication and then randomly distributed into the daughter nuclei.

Genes from both parents may be passed on to their children, especially if the genes are different. This process is called recombination, and it increases the variability of offspring.

Final Thoughts

With so many macromolecules in the body, it’s important to understand their functions and structures. This blog post has provided some of the most common types and structures for you to review. Do further research so that you can have a deeper understanding of how the common biological macromolecules work. A starting point would be familiarizing with the definition of various monomers or even the general terms used in macromolecules. Keep in mind that our top writers are ready to help you with that assignment in case you feel stuck. All you have to do is place an order with us.

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