The Biochemistry of Movement > 9.7.4. Proteins are used as both structural molecules and enzymes to catalyse metabolic reactions > The Chemical Features Of A Protein >
Explain, using a named example, the relationship between the chemical features of a protein and its shape using appropriate diagrams or models
- There are 20 different amino acids found in proteins. Protein molecules are made of long sequences of amino acids, which are connected by covalent peptide bonds.
- Thousands of proteins are known, and each one has a unique, specific amino acid sequence between 50-2000 amino acids long.
- When a polypeptide is formed, the side chain will remain the same.
- Primary structure is the amino acid sequence in the polypeptide chain.
- Secondary structure is the way in which the polypeptide chain folds.
- Tertiary structure refers to the way the secondary structure folds back upon itself or twists around to form a three-dimensional structure (the protein). This is the overall structure of the polypeptide chain.
- Quaternary structure: This is how multiple polypeptide chains join together.