2022 · Paper 1 · Question 5 · 9 marks
SaveDefine the quaternary structure of a protein.
Explain how two enzymes with different amino acid sequences can catalyse the same reaction.
Scientists investigated the effect of pH 8.4 and pH 7.5 on the activity of enzymes P and Q.
Figure 8 shows their results.
Describe what the scientists should place in the control tubes in this investigation.

