Proteins

• What is the monomer of protein?

  An amino acid
• What is a dipeptide?

  2 amino acids
• What is a polypeptide chain?

  more than 2 amino acids
• What is a protein?

  One or more polypeptide chains
• Amino acid structure

  
• How many different R groups are there?

  20
• How many amino acids are there?

  20
• Two amino acids are joined by what bond?

  Peptide bond

  
• Which groups are joined by a peptide bond in a condensation reaction between 2 amino acids?

  Amino group and carboxyl group

  
• Which two atoms are joined by the peptide bond?

  Hydrogen and oxygen

  
• Define primary structure

  The specific sequence of amino acids in a polypeptide chain forms the primary structure of a protein.
• Define secondary structure

  Hydrogen bonds form between amino acids forming Alpha helices or beta pleated sheets.
• Define tertiary structure

  Alpha helices and beta pleated sheets can be further folded to give a specific structure by either hydrogen bonds, ionic bonds or disulphide bridges.
• Which are the strongest bonds?

  Disulphide bridges
• Which bonds are easily broken?

  Hydrogen bonds
• Which are extremely vulnerable to change in pH?

  Ionic bonds
• Define quaternary structure

  Proteins made up of more than one polypeptide chain.
• Haemoglobin is described as a globular protein, with a spherical shape (compact and folded)
• Fibrous proteins, such as collagen, have structural functions
• Globular proteins, such as enzymes and haemoglobin, carry out metabolic functions.
• What is used to test for proteins and what colour does it go?

  Biuret test, purple for protein