6.3 Manipulating Genomes Flashcards
What is a genome ?
The genome of an organism is all the genetic material the organism contains.
What are introns ?
They are large non-coding regions of DNA before translation.
What are exons ?
Regions of DNA that code for proteins.
What is DNA profiling ?
Producing an image of patterns in DNA of an individual is known as DNA profiling.
Stages of producing a DNA profile
1) Extracting DNA
2)Digesting sample with cutting into smaller sections.
3) Separating DNA fragments using electrophoresis.
4)Hybridisation where dye is added.
5) Seeing the evidence
How are DNA fragments separated by electrophoresis ?
DNA samples are put into wells and an electrical current is passed through. DNA fragments move toward the positive anode due to DNA backbone being negatively charged. Smaller fragments move further to the bottom as there is less resistance.
What is PCR ?
Polymerase chain reaction that replicates DNA into millions of copies from a small original sample.
What is the first stage in PCR ?
DNA is heated to 95 degrees to denature strands by braking the hydrogen bonds, causing the strands to separate.
What happens at stage 2 in PCR ?
Sample is cooled to 55 degrees and primers are annealed and bind to ends of DNA. They are needed for replication to occur. It also signal for DNA polymerase to begin to bind.
What is stage 3 of PCR ?
Sample is heated back up to 72 degrees and this is where DNA is synthesised. This is the optimum temperature for DNA polymerase to work to add bases to the primer, building up complementary strands if DNA.
What are some uses of DNA profiling ?
Used in crime investigations, paternity testing and identifying individuals who are at risk of developing particular diseases.
How does Sanger sequencing work ?
1) DNA is mixed with primer, DNA polymerase and excess of normal nucleotides and terminator bases.
2) Mixer is placed in a thermal cycler.
3) Polymerase builds up new DNA strands.
4) Each time terminator base is added instead of normal base, sequence is stopped and fragments are separated.
5) Order of bases in capillary tubes show sequence of new, complementary strands of DNA.
What is bioinformation ?
Development of software and computing tools needed to organise and analyse raw biological data.
What is computational biology ?
Computational biology uses data to build theoretical models of biological systems, which can be used to predict what will happen in different circumstances.
What is genetic engineering ?
It is the manipulation of an organisms genome by isolating a gene for a desirable characteristic in one organism and placing it into another organism.
How do you isolated the desired gene in genetic engineering ?
Use restriction endonuclease enzymes to cut gene from DNA at specific bases sequences within the molecule. They cut strands unevenly leaving sticky ends.
How are vectors used in genetic engineering ?
Vectors are commonly used as bacterial plasmids. They can replicate independently and once inside the host cell, it can combine with host DNA to form recombinant DNA.
Why are plasmids often chosen to be used as vectors ?
They contain a marker gene that enables scientists to determine the bacteria that have taken up the plasmid.
How is the vector transferred?
Plasmid with the recombinant DNA must be transferred via transformation. One way is to culture bacterial cells in calcium-rich solution and increase the temperature. Or this can be done by electroporation where a small current is applied to the bacteria so membranes are porous and plasmids can move into the cells.
What is electrofusion ?
Another way to produce GM cells. Small electrical current are applied to the membranes of 2 different cells. This fuses cell and nuclear membrane of 2 cells together.
What are some ethical concerns with GM microorganisms ?
Some people were uncomfortable with inserting human genes into microorganisms but the results are now seen as extremely beneficial. They have been used safely for many years so there is now little ethical debate.
What are some benefits to GM crops ?
-Pest resistant so reduced amount of pesticides.
-Increase yield of crops.
-Can increases disease resistance.
-Herbicides can be used.
-Can survive in harsh conditions.
What are some negatives with GM crops ?
-Non pests may be hurt by toxins.
-Insect pests may become resistant to GM crops.
-Transferred genes may spread to wild population.
-Reduce biodiversity.
-People may be allergic.
-Large companies may financially benefit.
What are some examples of GM animals ?
-Swine fever resistant pigs
-Faster growing salmon.
What is pharming ?
One of the biggest uses of genetic engineering in animals with the production of human medicines.
-Creating animal models
-Creating human proteins.
What is the somatic cell gene therapy ?
Involves replacing the mutant alleles with a healthy allele in the affected somatic cells.
What is the germ line cell gene therapy ?
To insert a healthy allele into germ cells, or into an embryo immediately after fertilisation as part of in vitro fertilisation. The individual would be born healthy with the normal allele in place and would pass it on to their offspring.
