Proteins

Question 1

Compare and contrast the molecular structures of globular and fibrous proteins (4)

Answer 1

• both:
- chains of amino acids joined by peptide bonds
- contain hydrogen bonds

• globular has tertiary/quaternary structures but fibrous has little/no tertiary structures

• globular can be folded into compact shapes, fibrous has long chains

Question 2

Suggest how two amino acids could be brought closer together to form part of the active site of the enzyme (3)

Answer 2

• formation of secondary structure
• hydrogen bonding between R groups

Question 3

Describe how a peptide bond is formed (2)

Answer 3

• condensation reaction
• b/w amine group and carboxyl group of adjacent amino acids

Question 4

State why enzymes are described as biological catalysts (1)

Answer 4

• reduce activation energy of biological reactions