Biology 9700 · AS & A Level · Protein synthesis

Protein synthesis — practice question

Telomeres are stretches of DNA composed of repeating nucleotide sequences. Telomeres occur in eukaryotic chromosomes.
(a)[3]

Outline the function of telomeres in eukaryotic chromosomes.

(b(i))[1]

TERRA is transcribed from the DNA nucleotide sequence shown in Fig. 5.1. Fill in Fig. 5.2 so that it shows the six bases in the RNA sequence of TERRA.

(b(ii))[2]

Use Fig. 5.3 to state the two amino acids in the dipeptide translated from TERRA RNA.

(b(iii))[1]

Scientists have discovered that TERRA interacts with genes in stem cells. Increased concentrations of TERRA in stem cells result in a large increase in the number of genes that are transcribed. Suggest the result of the large increase in the number of genes that are transcribed in stem cells.

(ii)[2]

Fig. 5.3 shows DNA triplet codes on the non-transcribed strand of a gene, together with the amino acids specified by those triplets. The bases at the centre of the diagram indicate the first base in a triplet. Use Fig. 5.3 to state the two amino acids in the dipeptide translated from TERRA RNA.

(iii)[1]

Scientists have discovered that TERRA interacts with genes in stem cells. Increased concentrations of TERRA in stem cells result in a large increase in the number of genes that are transcribed. Suggest the result of the large increase in the number of genes that are transcribed in stem cells.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Enables repeated DNA replication

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