An enzyme is a chemical catalyst that speeds up or slows down a reaction without being changed or used up in the reaction itself.
Different amino acids
Protein is the most important nutrient. It is essential for every body cell.
Peptide link A chain of amino acids
Composition of proteins • Proteins are made up of the four elements carbon (C), hydrogen (H), oxygen (O) and nitrogen (N).
• Proteins are the only nutrient to contain nitrogen, which is necessary for the growth of new cells.
• Each protein is made up of a chain of smaller units called amino acids.
• Protein is made up of a chain of amino acids joined together by peptide links.
Peptide links broken A protein chain being broken down during digestion
During digestion, these peptide links are broken apart by enzymes, freeing each amino acid so that it can easily be absorbed into the bloodstream to keep the body nourished.
Revision Toolkit
Don’t Forget! Nitrogen is
only contained in protein.
Use the following mnemonic to help you remember the elements in protein: Ciara Has One Nephew Carbon Hydrogen Oxygen Nitrogen
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Strand 1: Food, Health and Culinary Skills Section 2: Nutrition Know-How