Protein (Leaving Cert Biology): Revision Notes
📚 Revision Notes
Protein
Proteins are composed of:
- Carbon
- Hydrogen
- Oxygen and
- Nitrogen
infoNote
Proteins, lipids, and carbohydrates are all composed of carbon, hydrogen, and oxygen. Nitrogen makes proteins different from lipids and carbohydrates.
In proteins, nitrogen forms amino acids, which are essential for growth and repair of body cells.
Protein
- Consists of repeating units of amino acids.
- There are 20 common amino acids.
- The bond between amino acids is called a peptide bond.
- A peptide is made of less than 20 amino acids.
- A polypeptide is made of 20+, protein is a long polypeptide chain.
- Amino acids link together in polypeptide chains to form proteins. An average protein is 500 amino acids long.
- Sources of protein include chicken, eggs and soya beans.
Role of Proteins
- Structural role: Keratin in hair and nails
- Metabolic role:
- Enzymes
- Hormones
infoNote
Structural role: involves building and supporting body structures Metabolic role: involves chemical reactions and processes that sustain life.
