Course Hero Logo




Carbon, found in all living organisms, is the basis for life. This is because carbon plays such an important role in basic biological functions. Carbon's bonding patterns allow it to form many different molecules and, with the addition of functional groups, serve many different roles. Smaller molecules can be bonded together to form much larger, complex molecules. These are known as macromolecules, which include three major classes: carbohydrates, proteins, and nucleic acids. Carbohydrates are vital for the cell, as they provide energy and structural support. Proteins perform a wide variety of functions for the cell, such as structural support and enzymes. Nucleic acids are the genetic blueprint and carry all of the instructions for the cell. While lipids are not commonly classified as macromolecules because of their difference in size when compared to carbohydrates, proteins, and nucleic acids, they do provide energy and structural support to the body. Without carbon, none of these organic molecules would exist, resulting in the inability of a cell to function.

At A Glance

  • Carbon is a unique atom that not only has unique bonding properties, but is also the precursor for very large molecules that primarily contain chains and rings.
  • Functional groups are collections of several different groups of atoms, within molecules, that have specific characteristics and play a role in the formation of key biomolecules, such as nucleic acids and proteins.
  • Carbon's unique chemical bonding with other atoms contributes to its ability to form biomolecules, such as macromolecules, which serve as building blocks for many larger kinds of molecules or polymers.
  • Recognized as sugars and starches, carbohydrates are a class of molecules that primarily function to provide energy for various cellular processes.
  • Lipids are molecules that are classified as triglycerides, phospholipids, and steroids, all of which play a key role in various biological functions.
  • Regarded as substances that do a lot of work in living things, proteins are macromolecules made from smaller subunits called amino acids that provide structure and storage and help regulate biological processes.
  • Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are two types of macromolecules that play a role in the genetic makeup of living things.