19 Genetic technology
The discovery in the early 1950s of the structure of DNA by Watson and Crick, supported by the work of
Franklin, Wilkins and
... [Show More] Chargaff, and discoveries since, have led to many applications of genetic technology in
areas of medicine, agriculture and forensic science. This topic relies heavily on prior knowledge of DNA and RNA
structure and protein synthesis from the topic on Nucleic acids and protein synthesis (Topic 6).
Candidates will benefit from carrying out practical work using electrophoresis, either with DNA or specially
prepared dyes used to represent DNA.
19.1 Principles of genetic
technology
Learning outcomes
Candidates should be able to:
1 define the term recombinant DNA
2 explain that genetic engineering is the deliberate manipulation
of genetic material to modify specific characteristics of an
organism and that this may involve transferring a gene into an
organism so that the gene is expressed
3 explain that genes to be transferred into an organism may be:
• extracted from the DNA of a donor organism
• synthesised from the mRNA of a donor organism
• synthesised chemically from nucleotides
4 explain the roles of restriction endonucleases, DNA ligase,
plasmids, DNA polymerase and reverse transcriptase in the
transfer of a gene into an organism
5 explain why a promoter may have to be transferred into an
organism as well as the desired gene
6 explain how gene expression may be confirmed by the use of
marker genes coding for fluorescent products
7 explain that gene editing is a form of genetic engineering
involving the insertion, deletion or replacement of DNA at
specific sites in the genome
8 describe and explain the steps involved in the polymerase chain
reaction (PCR) to clone and amplify DNA, including the role of
Taq polymerase
9 describe and explain how gel electrophoresis is used to separate
DNA fragments of different lengths
10 outline how microarrays are used in the analysis of genomes
and in detecting mRNA in studies of gene expression
11 outline the benefits of using databases that provide information
about nucleotide sequences of genes and genomes, and amino
acid sequences of proteins and protein structures
19.2 Genetic technology applied
to medicine
Learning outcomes
Candidates should be able to:
1 explain the advantages of using recombinant human proteins
to treat disease, using the examples insulin, factor VIII and
adenosine deaminase
2 outline the advantages of genetic screening, using the examples
of breast cancer (BRCA1 and BRCA2), Huntington’s disease and
cystic fibrosis
3 outline how genetic diseases can be treated with gene therapy,
using the examples severe combined immunodeficiency (SCID)
and inherited eye diseases
4 discuss the social and ethical considerations of using genetic
screening and gene therapy in medicine
19.3 Genetically modified
organisms in agriculture
Learning outcomes
Candidates should be able to:
1 explain that genetic engineering may help to solve the global
demand for food by improving the quality and productivity of
farmed animals and crop plants, using the examples of
GM salmon, herbicide resistance in soybean and insect
resistance in cotton
2 discuss the ethical and social implications of using genetically
modified organisms (GMOs) in food production [Show Less]