9700 · 19.2
Genetic technology applied to medicine flashcards
Revision flashcards for Cambridge 9700 Genetic technology applied to medicine (syllabus 19.2). Flip, recall, then mark a real past-paper question.
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What is gene therapy?
A medical technique that aims to treat or cure genetic disorders by introducing a normal, functional gene into a patient's cells to replace or supplement a faulty or missing gene.
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What is a 'vector' in the context of gene therapy?
A delivery vehicle, typically a modified virus (like an adenovirus) or a synthetic liposome, used to carry a therapeutic gene into target cells.
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Distinguish between *in vivo* and *ex vivo* gene therapy.
*In vivo* therapy involves delivering the therapeutic gene directly into the patient's body. *Ex vivo* therapy involves removing cells from the patient, genetically modifying them in the lab, and then returning them to the patient.
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What is CRISPR-Cas9?
A powerful and precise gene-editing tool that uses a guide RNA (gRNA) to direct the Cas9 enzyme to a specific DNA sequence, where it makes a double-stranded cut. This allows for the removal, replacement, or insertion of genes.
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What is the function of the guide RNA (gRNA) in the CRISPR-Cas9 system?
The gRNA is a short RNA sequence designed to be complementary to the target DNA. It acts as a guide, leading the Cas9 enzyme to the precise location in the genome that needs to be edited.
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What is genetic screening?
The process of testing individuals in a population for a specific allele, gene mutation, or chromosomal abnormality to identify if they have a genetic disorder, are carriers, or have a predisposition to a disease.
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What is Preimplantation Genetic Diagnosis (PGD)?
A genetic screening technique used during in vitro fertilisation (IVF). It involves testing embryos for specific genetic conditions before they are implanted in the uterus, allowing for the selection of unaffected embryos.
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What is the key ethical difference between somatic and germline gene therapy?
Somatic cell therapy affects only the individual being treated and the changes are not heritable. Germline therapy targets reproductive cells (sperm or eggs), meaning the genetic changes would be passed on to all future generations, which raises profound ethical concerns.