Lecture 6- Analysing the human genome Flashcards
3 characteristics of the human genome?
located on 3 individual chromosomes
approximately 30,000 expressed genes
three billion nucleotides
Hybridisation
a way to separate the two strands of DNA by heat into a single stranded DNA,
gives us a method to identify a particular sequence is present.
Restriction enzymes
molecular scissors for cutting up DNA into segments
they recognise a particular sequence of bases along the DNA and cut at a particular point.
sticky ends
piece of DNA that is flap of single stranded DNA hanging off a section of double stranded DNA.
How can you clone a human genome?
1) extract DNA from a human cell
2) Add restriction enzyme to break up dna into gene size pieces
3) remove a gene and insert into plasmid
describe bacterial dna?
bacteria has a main DNA- single large circular chromosome and plasmid DNA (small rings)
How can a human gene be inserted into a plasmid?
1) Extract plasmid from bacteria
2) Add psc 1 restriction enzyme
3) this cuts at AMC site of plasmid
4) add gene of human to the plasmid
5) enzyme joins up the gene into plasmid with AMC site
6) insert plasmid back into bacteria and grow it into a culture
what is the role of tetracycline during cloning of plasmid with desired human gene?
we only want our human gene plasmid to grow and not any other contaminated plasmid so we add another gene into the plasmid that makes it resistant to tetracycline. We can then add tetracycline into the medium and this will kill all of the bacterial plasmids that are not resistant to tetracycline.
what is the relative importance of cloning a gene?
to study the gene extracted as we can find out what proteins it makes and whether they are useful then we can go ahead and make large quantities.
which protein can protect us against Herpes simplex virus?
Interferon can protect us against herpes simplex virus.
when may a cell release interferon?
when invaded by a virus
how can a virus stimulate the host genome to make many copies of interferon?
virus enters the cells, causes genome to make mRNA for interferon. Interferon made at ribosomes in cytoplasm and then released to combat viruses.
what disease does HIV virus cause?
AIDs
what are the three advantages of gene therapy?
- to repair a damaged gene
- to remove defect genes
- add new gene to carry out a new function
Describe how gene therapy can help to counter HIV?
Remove stem cells from bone marrow and use a bienign virus to carry a new gene into the nucleus of cell, new gene joins with existing gene to make a new protein which will destroy HIV virus. Inject stem cells back into bone marrow so when they mature they will make HIV proof cells.
