Table 1 shows selected aspects of protein structure and the level of protein structure to which each belongs.
Table 1
Aspect of protein structure | Level of structure / primary, secondary, tertiary, quaternary |
α-helix | secondary |
Disulfide bridge | |
Sequence of amino acids | |
β-pleated sheet | |
Separate polypeptide chains interacting | |
Hydrogen bonds | |
Ionic bonds |
Complete Table 1 by using the terms primary, secondary, tertiary and/or quaternary.
The first row has been completed for you.
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.
The Biuret test is a biochemical test for proteins.
State the colour change observed in a positive Biuret test.
The Biuret test is a qualitative test for proteins.
Explain why the Biuret test is referred to as 'qualitative'.
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