Biology 9700 · AS & A Level · Genetic technology applied to medicine

Genetic technology applied to medicine — practice question

An autosomal recessive mutation is the cause of the immune system disorder adenosine deaminase (ADA) deficiency. Severe combined immunodeficiency that results from a lack of ADA is known as ADA-SCID.
(a)[4]

Genetic engineering is applied to produce a recombinant human protein to treat people with ADA-SCID. Outline the principles of genetic engineering.

(b(i))[2]

Explain why a single infusion of gene-corrected stem cells is enough to cure the disease.

(b(ii))[2]

Explain why a promoter must be transferred in addition to the target gene.

(b(iii))[2]

A modified retrovirus is employed to place the new gene into the DNA of the blood stem cells. State two ethical considerations of using a retrovirus for gene therapy.

(c)[3]

The gene therapy technique used to cure ADA-SCID is not suitable for treating the genetic disease called Huntington’s disease. A newer technique called gene editing could potentially be used instead to cure Huntington’s disease. Explain why gene editing is more suitable as a potential cure for Huntington’s disease.

Worked solution & mark scheme

This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: introduce DNA to provide a new named characteristic or protein

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