Which bonds hold the secondary structure of helices and sheets?

• Peptide bonds between side chains
• Hydrogen bonds between backbone parts
• Sulfur bridges between separate chains

Which bonds hold the primary structure of a protein?

• Peptide bonds between amino acids
• Hydrogen bonds between backbone parts
• Ionic attractions between folded chains

Quaternary structure packs several folded chains together.

A protein is gently heated. Which bonds break first?

• The hydrogen bonds and ionic grips
• The tough peptide bonds of the order
• Every bond at exactly the same moment

Why does one swapped amino acid cause sickle cell disease?

• It deletes the whole haemoglobin chain
• It adds an extra chain to every protein
• The fold shifts so fibres clump

Where do water fearing side chains end up during folding?

• Spread evenly across the surface
• Buried inward, away from water
• Broken off and discarded

A student says quaternary structure means one chain folded four times. What is wrong?

• A single chain cannot fold on its own without any help in cells
• Only two levels exist in every protein
• Quaternary packs several folded chains together

Boiling an egg breaks its peptide bonds, which is why it cannot uncook.