Manipulating Genomes Flashcards
What is DNA sequencing
Identifying the base sequence of a DNA fragment
How have sequencing methods changed overtime
Used to be a manual process however now it has become automated
Entire genomes can now be read
Give some benefits of genome-wide comparisons
Comparing between species allows us to determine evolutionary relationships
Comparing between individuals of the same species allows us to tailor medical treatment to the individual
How can DNA sequencing be used in synthetic biology
Knowing the sequence of a gene allows us to predict the sequence of amino acids that will make up the polypeptide that it produces.
This in turn allows for the development of synthetic biology
What is DNA profiling
Identifying the unique areas of a person’s DNA, in order to create a profile that is individual to them
Give uses of DNA profiling
Forensics= DNA obtained during crime investigations can be compared to that of victims or suspects
Medicine = to screen for a particular base sequence in order to identify inheritable diseases
How can we amplify DNA fragments in order to sequence them
Using the polymerase chain reaction
Makes millions of copies of a fragment, which are then cut at different lengths in order to be sequenced
Describe the reaction mixture in the first stage of PCR
Contains the DNA fragment to be amplified, primers which are complimentary to the start of the fragment, free nucleotides to match up to exposed bases, and DNA polymerase to create the new DNA
Summarise the process of amplifying DNA fragments using PCR
Heated to break apart the DNA strands
Cooled to allow primers to build
Heated again to active DNA polymerase and allow free nucleotides to join
New DNA acts as template for the next cycle
How is gel electrophoresis used in DNA profiling
DNA fragments at varying lengths are placed at one end of a slab of gel
Electric current is applied; DNA fragments move towards the other end of the gel
Shorter fragments travel further. The pattern of bands created is unique to every individual
What is meant by genetic engineering
Where a DNA fragment from one organism is inserted into the DNA of another organism, sometimes across species. This is done through the use of a vector and host cell
Summarise the process of isolating a DNA fragment
Restriction enzymes (RE) cut DNA at specific sequences. Different REs cut at different points, but one RE will always cut at the same sequence. Therefore using particular REs allows you to cut out a certain gene of interest
Summarise the process of inserting a DNA fragment into a vector
A plasmid (circular DNA from bacteria) is used as the vector, and is cut using the same restriction enzymes as the DNA, so that the ends are complementary. DNA ligase joins the fragment and plasmid together
Summarise the process of inserting a vector into a host cell
The host cells (bacteria) are mixed with the vectors in an ice-cold solution, then shocked to increase the permeability of the cell membrane (electroporation) which encourages the cells to take up the vectors
Give some ethical issues around genetic engineering
+ Insect resistance can be introduced to crops
+ GE animals used to produce pharmaceuticals (pharming)
+ GE pathogens can be produced for research
- GE seeds would be harder to acquire for poorer farmers
