File - Leaving Cert Biology

Chapter 18: Genetic
Leaving Certificate Biology
Higher Level
Genetic Engineering
• Genetic engineering is the manipulation and
alteration of genes in basic and applied
– Involves the introduction of foreign genes into an
organism’s genetic material using plasmids and
restriction enzymes
– Genes can be transferred between organisms that
are evolutionary very distant – e.g. humans and
– DNA that contains a foreign gene is called
recombinant DNA
Genetic Engineering
• The following steps are involved in producing
recombinant DNA:
1. Isolation: removal of DNA that carries gene of interest
and removal of vector DNA (e.g. plasmids from E. coli)
2. Transformation: is the uptake and insertion of foreign
DNA into the DNA of the host – involves:
• Cutting – human DNA and bacterial plasmid are both cut by
specific restriction enzyme. Human DNA now has sticky ends
• Ligation (splicing) – DNA ligases help the human DNA fragments
to insert into the open plasmid in the correct orientation
3. Expression: activation of the gene to produce a
specific protein (e.g. human insulin)
Applications of Genetic
• Plant: crop plants can be genetically modified by
inserting a bacterial gene that gives them
resistance to specific herbicides
• Animal: sheep have been genetically modified
to carry the human blood clotting factor gene
such that it can only be expressed in the
mammary glands – then the human blood
clotting factor is extracted from the sheep’s milk
• Microorganism: bacteria have been genetically
modified to carry the human insulin gene so that
they can produce large amounts of the protein
insulin in culture
Related flashcards

Population genetics

22 cards

Population genetics

25 cards


23 cards


21 cards


15 cards

Create Flashcards