1.1. Table 1 shows selected aspects of protein structure and the level of protein structure to which each belongs.

Table 1

Complete Table 1 by using the terms primary, secondary, tertiary and/or quaternary.

The first row has been completed for you.

1.2. Two types of proteins are shown in Fig. 1. They are labelled Protein A and Protein B.

Fig. 1

Identify which of A or B is a globular protein and give a reason for your choice.

1.3. The Biuret test is a biochemical test for proteins.

State the colour change observed in a positive Biuret test.

1.4. The Biuret test is a qualitative test for proteins.

Explain why the Biuret test is referred to as 'qualitative'.