The figure shows a tripeptide.

Label one peptide bond in this molecule.

Describe the secondary structure of proteins.

Outline the action taken by the diaphragm during inhalation.

circle/bracket around peptide bond / arrow pointing to peptide bond / peptide bond labelled;

Allow either peptide bond

Allow if adjacent C=O and NH groups are included in the circle/bracket, but do not allow if other parts of the molecule are included.

a. polypeptide wound into a helical structure / alpha/α helix
OR
polypeptide folded back on itself forming a pleated sheet / beta/β pleated sheet;
b. stabilized/held in shape by/due to hydrogen bonds (between C=O and N-H groups);
c. secondary structures are regular/unvarying (within polypeptides/proteins);

Allow annotated diagrams

contracts/flattens/becomes less domed/increases volume of thorax;

80 % of candidates indicated one of the two peptide bonds in the diagram correctly.

There were some good answers here describing secondary structures and the role of hydrogen bonding.

80 % of candidates knew that the diaphragm contracts than relaxes during inhalation, or stated that it flattens rather than moves upwards.