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What is a protein?

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Quick answer

A protein is a large molecule made of building blocks called amino acids, folded into a specific shape that lets it do a job in living things. Proteins build and repair tissue, speed up reactions (as enzymes), carry oxygen, fight infection, and much more — they're the workhorses of every cell.

Key things to understand

  1. Proteins are long chains of amino acids folded into precise 3D shapes.
  2. Your DNA carries the instructions for which amino acids to string together to make each protein.
  3. They do almost every job in the body: enzymes (speed reactions), antibodies (fight germs), haemoglobin (carries oxygen), muscle fibres, and more.
  4. There are 20 amino acids; the order and folding determine what a protein does.
  5. We get the amino acids to build them from protein in food — meat, beans, eggs, dairy.

People also ask

What are proteins made of?
Amino acids — small molecules linked in a chain. There are 20 kinds, and their sequence (set by your DNA) folds into the protein's working shape.
What do proteins do in the body?
Almost everything: they form muscle and tissue, act as enzymes that speed up reactions, carry oxygen, make antibodies, and send signals as hormones.
Why do we need protein in our diet?
Food protein is broken down into amino acids, which your body reuses to build its own proteins for growth, repair, and countless functions.
What do proteins do?
They build and repair tissue, act as enzymes, carry molecules, and form antibodies — doing most cellular work.
How are proteins made?
Cells read instructions in DNA to assemble amino acids into the right protein.

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