Protein Structures

Question 1

Protein structure - primary

Answer 1

• this is the order of amino acids in a polypeptide chain
• the order is decided by the DNA
• the bond between each amino acid is a peptide bond

Question 2

Protein Structure - secondary

Answer 2

• this is the shape that the polypeptide chain forms due to hydrogen bonds
• hydrogen bonds twists and fold the polypeptide forming an alpha helix, or beta pleated sheet

Question 3

Protein structure - tertiary

Answer 3

• alpha helix is further folded
• shape is maintained by disulphide, ionic bonds
• enzymes have a tertiary structure

Question 4

Protein structure - quaternary

Answer 4

• combination of two or more polypeptide chains in tertiary form
• associated with non-polar groups and form large complex molecules, e.g. haemoglobin