2.3.3 Protein Shape

Question 1

Describe the disulphide bonds

Answer 1

• occurs only between cysteine groups (only R groups with sulfur atom)
• strong covalent bonds but occur less
• broken by reduction
• common in protein release (e.g. insulin)

Question 2

Describe ionic bonding

Answer 2

• between positively charged (+NH2) and negatively charged (-COOH-) R groups
• stronger than hydrogen but not common
• broken by pH changes

Question 3

Describe the hydrogen bonding

Answer 3

• forms between a variety of R groups
• weak in isolation but many can form a strong structure

Question 4

Describe the hydrophobic interactions

Answer 4

• form between the non-polar R groups
• if a protein is watery the hydrophobic R groups come together excluding water