A-LevelBiologyBiological molecules9700/12 · Feb/Mar 2025 · Q101 Mark
Hydroxyproline is synthesised by addition of an –OH group to the R-group of the amino acid proline. Hydroxyproline is a major component of collagen and has an important role in increasing the stability of its structure. Which statement explains why the addition of an –OH group to proline could increase the stability of collagen?
AIt strengthens hydrogen bonding between the R-groups of adjacent polypeptide chains, resulting in a tertiary structure that is more resistant to heat denaturation.
BIt increases the number of sites available for the formation of hydrogen bonds within the secondary structure of collagen, resulting in more stable alpha helices.
CIt increases the formation of hydrogen bonds between R-groups and water molecules, which help to hold the chains of the collagen triple helix together by strengthening hydrophilic interactions.
DIt strengthens the quaternary structure of collagen by providing more sites for hydrogen bonding between the R-groups of distantly separated amino acids within the same polypeptide chain.
✓ Correct answer
C: It increases the formation of hydrogen bonds between R-groups and water molecules, which help to hold the chains of the collagen triple helix together by strengthening hydrophilic interactions.
Practise more questions on this topic
Oracle Prep sorts past-paper questions by topic, so you can drill Biological molecules and see which topics are most likely to come up next.
Sign up free →