Proteins and Lipids


Proteins are large molecules made from amino acids, which are joined to form long chains. Unlike lipids and carbohydrates, proteins contain nitrogen and sometimes sulfur. Some examples of proteins are:

  • Enzymes
  • Haemoglobin
  • Insulin
  • Keratin

Proteins contribute to the biochemical processes that preserve life. They are involved in the structure and functions of living cells and are one of the basic components of cellular membranes.

Every protein is made up of many amino acids joined together in a unique sequence. The long chains of amino acids fold into unique shapes.

There are only around 20 different types of amino acids; however, they can be arranged in different sequences. This is why there are many different types of proteins.

  • The amino acid sequence determines the 3D structure of the protein and its specific function.


Lipids, including fats and oils, are biological molecules made up of carbon, hydrogen, and oxygen.

Most fats in the body are made up of triglycerides. A basic unit of a triglyceride consists of one glycerol molecule chemically bonded to three fatty acid chains.

The fatty acid chains vary in size and structure.

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