Biology 9700 · AS & A Level · Protein synthesis

Protein synthesis — practice question

Food crops like barley and wheat contain gluten. Gluten is made up of two proteins, glutenin and gliadin.
(a(i))[3]

Table 4.1 gives descriptions of the structures of glutenin and gliadin. Complete Table 4.1 by writing the protein structure level that matches each description.

(a(ii))[1]

Many genes in eukaryotic cells contain introns. The genes that code for gliadin do not contain introns. Explain how the absence of introns in a gliadin gene changes the formation of mRNA from the primary transcript.

(b(i))[2]

The gliadin peptides produced by digestion are often as long as 33 amino acids. Intestinal cells absorb large numbers of these peptides at the same time. Suggest and explain how gliadin peptides are transported into intestinal cells.

(b(ii))[4]

The presence of gliadin causes the immune system of a person with coeliac disease to respond by making anti-gliadin antibodies. Describe the sequence of events that leads to anti-gliadin antibody production by the immune system.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: A single polypeptide folded into a compact form identified as tertiary

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