Nutritional Requirements for Cells: Elements & Roles

Instructor: Bridgett Payseur

Bridgett has a PhD in microbiology and immunology and teaches college biology.

Cells need nutrition in order to get the required elements. Which specific foods provide specific elements, and what do those elements do in the cell? Read on to learn how cells use their food.

What Do Cells Eat?

Even though they don't have mouths or stomachs, single-celled organisms still need to eat. While different types of cells might need different specific nutrients, all living things require the same basic elements.

The four most abundant elements in living things are:

  • carbon
  • hydrogen
  • oxygen
  • nitrogen

Other elements, including phosphorus, calcium, and iron, are also important, but are needed in much smaller quantities.

Every living cell is made of some combination of the same 20 elements. Cells get these elements by taking them in from their environment. They can come from a variety of different food sources, some of which are small molecules, like salts and water. Other elements come from larger macromolecules, like starches, proteins, and fats.

Elements from Macromolecules

The macromolecules (big molecules) are probably what you think of when you think about food. These are the basic, energy-providing molecules discussed in biology class. They mostly provide the elements used for making the main pieces of the cell. The four major macromolecules are:

  • carbohydrates
  • lipids
  • proteins
  • nucleic acids

Carbohydrates and lipids are both made of carbon, hydrogen, and water, which are all found in the major macromolecules of a cell.

In addition to carbon, hydrogen, and oxygen, proteins can provide a few other elements. All amino acids contain nitrogen, which is an important element in the structure of proteins and nucleic acids. Some proteins also contain sulfur. In addition to being a part of protein structure, sulfur can act as a cofactor for certain enzymes.

Nucleic acids provide the usual carbon, hydrogen, and oxygen, but also contain phosphorus. Phosphorus is found in DNA, as well as the molecules used by the cell to store energy.

Elements from Other Molecules


One thing that all cells need is water. Water provides cells with both hydrogen and oxygen. Both of these elements are used to build larger molecules, such as sugars, proteins, and fats. However, hydrogen and oxygen both play important roles in cellular respiration, which cells use to produce and store energy.

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