3.8.4 Gene Technologies Flashcards
Determining the genome of simpler organisms allows
The sequences of proteins that derive from the genetic code of the organism to be determined
Why can’t genome knowledge by easily translated into proteome
Non-coding DNA and regulatory genes
Recombinant DNA tech involves
Transfer of DNA fragments from one organism or species to another
Genetic code, transcription translation mechanisms are
Universal
What can you do with transferred DNA
Translate into cells in transgenic organism
In vivo method to amplify DNA
DNA insert attached to plasmid
Plasmid + Gene cut with same restriction enzyme to create complementary sticky ends Fragments incubated with plasmids
Base pairing takes place
Joined with DNA ligase which forms phosphodiester linkages
What do restriction enzymes do
Cuts DNA into gene-sized pieces
How is reverse transcriptase used to amplify DNA
Remove mRNA from cell
Add reverse transcriptase
Convert RNA into DNA
Forms double stranded DNA
PCR amplifies DNA
Uses of genetic fingerprinting
Analysing DNA fragments that has been cloned by PCR + determining genetic relationships + genetic variability in a population
Forensic science
Medical diagnosis
Plant + animal breeding
Uses of DNA probes
Locate specific alleles of genes
Screen patients for heritable conditions, drug responses, health risks
What can be used to detect genetically modified cells in organisms
Marker genes
What is meant by recombinant DNA technology
The transfer of DNA fragments from one organism to another
Why does recombinant technology work
Genetic code is universal
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 complementary to the target Gene us used as a template
Mixed with free nucleotides which match up to complementary base pairs and reverse transcriptase which forms sugar-phosphate backbone, to create cDNA
Summarise the process of inserting a DNA fragment into a vector
A plasmid used as vector
Cut with same restriction enzyme as DNA so ends are complementary
DNA ligase joins fragment and plasmid together
Summarise the process of using enzymes to produce DNA fragments
Restriction endonucleases cut DNA at specific sequences
Different REs cut at different points but one RE will always cut same sequence
So using particular REs allow you to cut out certain Gene of interest
Summarise the process of inserting a vector into a host cell
Cell transformation
Host cells mixed with vectors in an ice-cold solution + heat to encourage cells to take up the vectors
The cells can then be grown and the DNA fragment cloned
Summarise the process of identifying transformed cells
Marker genes inserted into vectors along with DNA
When cells 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, amplified using PCR, then added to a sample of single stranded DNA
The probe will bind if the allele is present
3 applications of DNA probes
Screen someone’s DNA for particular heritable health condition
Identify a gene for use in genetic engineering
To predict how someone will respond to a drug
Purpose of DNA hybridisation
Measure the degree of difference between 2 DNA stands
Can be used to compare someone’s DNA to a certain gene to see if they have it
Summarise the process of DNA hybridisation
One DNA stand is labelled and mixed with an unlabelled comparison strand
More similar the strands, the more strongly they will bind
More energy required to break strands apart
Benefits of genetic profiling
Identifying heritable diseases early
Treatment can be personalised
What is genetic fingerprinting
Technique used to compare 2 DNA samples + determine weather they came from same individual
How does genetic fingerprinting work
Every organism’s genome contains non-coding regions called variable number tandem repeats
Probability of 2 individuals having the same VNTRs is very low, so we can compare these areas to see if 2 DNA samples came from same person
Summarise the process of genetic fingerprinting analysis
DNA sample obtained
VNTRs cut out using restriction enzymes
Labelled + cloned using PCR
Fragments separated using gel electrophoresis
Banding patterns of each sample can be compared
How does gel electrophoresis work
DNA fragments are placed at one end of a slab of gel
Electrical current applied causing the DNA fragments to move towards the other end of the gel
Shorter fragments travel further
Pattern of bands created unique to every individual
Applications of genetic fingerprinting
Forensics identify victims or suspects
Medical diagnosis e.g. to identify type of haemoglobin produced by an individual to diagnose sickle cell anaemia
Animal + plant breeding (breed out harmful alleles)
