Protein structure

Question 1

Primary structure

Answer 1

• 20 amino acids
• precise sequence
• change in amino acid alters properties
• peptide bonds

Question 2

Secondary structure

Answer 2

• alpha helix coil
• beta pleated sheet
• peptide, hydrogen bonds

Question 3

Tertiary structure

Answer 3

• coils and pleats fold again to give 3Dshape
• bonds holding 3D shape only form if amino acid sequence is correct
• peptide,hydrogen,disulphide,ionic and hydrophobic bonds

Question 4

Quaternary structure

Answer 4

• two or more polypeptide chains in tertiary form held together
• associated with non-protein groups