Gene Technologies Flashcards
what is meant by recombinant DNA technology
transfer of DNA fragments from one organism to another
why does recombinant DNA technology work
because genetic code is universal and therefore transcription and translation occur by the same mechanism and result in the same amino acid sequence across organisms
summarise the process of using reverse transcriptase to produce DNA fragments
mRNA complimentary to the target gene is used as a template
mixed with free nucleotides which match up to their base pairs and reverse transcriptase which forms the sugar-phosphate backbone, to create cDNA (complementary DNA)
summarise the process of using enzymes to produce DNA fragments
restriction endonucleases (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
in which two ways can we amplify DNA fragments
- in vitro (polymerase chain reaction PCR)
- in vivo (using host cells)
describe the reaction mixture in the first stage of PCR
contains the DNA fragment to be amplified, primers that 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 bind
- heated again to activate DNA polymerase and allow free nucleotides to join
- new DNA acts as template for next cycle
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
known as cell transformation
host cells (bacteria) are mixed with the vectors in an ice-cold solution, then heat shocked to encourage the cells to take up the vectors
the cells can then be grown and the DNA fragment will be cloned
summarise the process of identifying transformed cells
marker genes can be inserted into vectors along with the DNA
when cells begin to grow, UV light can be used to identify which cells have taken up the vector and which haven’t
how can DNA probes be used to locate specific alleles
probe designed so that its sequence is complementary to the allele you want to find.
they are labelled and amplified using PCR, then added to a sample of single stranded DNA
probe will then bind if the allele is present
how can DNA probes be used to locate specific alleles
probe designed so that its sequence is complementary to the allele you want to find.
they are labelled and amplified using PCR, then added to a sample of single stranded DNA
probe will then bind if the allele is present
give some applications of DNA probes
- screen someone’s DNA for a particular heritable health condition
- to identify a gene for use in genetic engineering
- predict how someone will respond to a drug
what is the purpose of DNA hybridisation
to measure the degree of difference between two strands of DNA
can be used to compare someone’s DNA to a certain gene to see if they have it
what is the purpose of DNA hybridisation
to measure the degree of difference between two strands of DNA
can be used to compare someone’s DNA to a certain gene to see if they have it
