Biology 9700 · AS & A Level · Protein synthesis

Protein synthesis — practice question

Cathelicidin LL-37 is a cell signalling compound that can activate many different human cells. One function of cathelicidin LL-37 is to stimulate the production of endothelial cells as capillaries form during wound healing.
(a(i))[2]

Explain how many different cell types are able to respond to the same cell signalling compound.

(a(ii))[2]

Describe what the endothelial cells of a capillary look like.

(b(i))[1]

Mutations in a gene’s DNA base sequence can alter the primary structure of proteins. Use the information in Table 5.1 and Table 5.2 to suggest what happens to the primary structure of cathelicidin LL-37 when the base T in the middle of the triplet at position 5 is replaced by base A.

(b(ii))[2]

Mutations in a gene’s DNA base sequence can alter the primary structure of proteins. Use the information in Table 5.1 and Table 5.2 to suggest what effect the deletion of base T from the triplet at position 2 has on the primary structure of cathelicidin LL-37.

(b(iii))[2]

Mutations in a gene’s DNA base sequence can alter the primary structure of proteins. Use the information in Table 5.1 and Table 5.2 to suggest what effect the insertion of base G between bases G and T in the triplet at position 3 has on the primary structure of cathelicidin LL-37.

(c)[1]

The genetic code is described as universal. Explain why the genetic code is described as universal.

(d)[2]

Use Table 5.2 to explain why some mutations do not affect the primary structure of a protein.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Cells possess specific receptors

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