Unit 19: Gene Tech (JW) Flashcards

Question

Explain why primers are used in PCR

Answer 1

primers bind to specific bases on DNA by CBP during annealing so that so that Taq polymerase can bind to DNA -> replicate DNA

Answer 2

DNA phosphate group -vely charged moves to anode when current applied larger fragment move more slowly due to resistance buffer solution

Answer 3

DNA cut with restriction enzymes DNA fragments placed in well in gel AT CATHODE current applied fragments negatively charged due to phosphate group move towards positive electrode/anode gel acts as a molecular sieve smaller fragments move faster than larger ones current switched off Southern blotting Staining for visualisation compare banding patterns to reference bands alleles have diff positions on gel

Answer 4

obtain ssDNA label ssDNA with fluorescent dye probes on microarray probes are short lengths of ssDNA complementary to DNA being tested for many copies of 1 type of probe placed in each cell of microarray DNA binds to/hybridises with probes unbound/excess DNA washed off UV light used to detect presence of fluorescence fluorescence indicates presence of gene intensity of fluorescence indicates level of gene expression positions recorded by laser/scanner positions identified as named genes

Answer 5

probes are ss DNA each probe unique to a particular gene probes correspond to thousands of different genes extract mRNA from 2 samples mRNA used as template to make cDNA using reverse transcriptase cDNA linked to fluorescent dye cDNA added to microarray cDNA binds to probes by complementary base pairing excess cDNA washed off exposed to UV light fluorescent shows expressed genes intensity of fluorescence shows level of gene expression positions recorded by laser/scanner positions identified as named genes

Answer 6

bioinformatics is a large database of DNA sequence data for comparison to search for DNA sequence similar to human protein modelling/predicting 3D protein structure DNA sequence data from all around the world fast, efficient, accurate determine percentage similarity

Answer 7

bacteria plasmids modified to include human insulin gene recombinant plasmids inserted into E coli by transformation once transgenic bacteria are identified, they are isolated, purified and placed into fermenters that provide optimal conditions transgenic bacteria multiply by binary fission transgenic bacteria express the gene coding for insulin insulin extracted and purified

Answer 8

kidney & ovary hamster cells genetically modified to produce factor VIII once modified, recombinant cells placed into fermenter and cultured optimal conditions in fermenter -> hamster cells constantly express factor VIII protein factor VIII protein extracted and purified injectable treatment for haemophilia

Answer 9

larva of the cabbage looper moth has been genetically modified (using a virus vector) produce ADA enzyme used as treatment whilst patients wait for gene therapy / if gene therapy not possible

Answer 10

identical to human protein produce in larger quantities no allergic reaction / side effects human protein may have higher activity no chance of developing tolerance no risk of transmitting diseases unlimited supply lower cost of production quicker to produce no ethical/religious issues easier to obtain purified product

Answer 11

early treatment lifestyle changes elective mastectomy regular checkups prevents unnecessary prolonged suffering if discovered and treated early prevents early death removes worry can choose whether to have children preventative = cheaper than later treatment

Answer 12

may cause worry person may not develop cancer test is expensive - not available for everyone social/financial discrimination - implications for life insurance may decide not to have children

Answer 13

quickly start treatment after birth informed decision made about continuing with pregnancy (if screened before birth) mentally prepare for cost of treatment does not rely on family knowing family history of SCID (example of SCID) prevents child with SCID from developing infections before diagnosis

Answer 14

dominant allele so will still be expressed even in presence of recessive allele gene therapy only used to treat recessive diseases cannot remove dominant allele dominant allele affects tissues in many part of the body

Answer 15

treat diseases such as SCID, CF caused by faulty/recessive allele deliver gene into target cell of individuals

Answer 16

synthesise dominant allele from mRNA using reverse transcriptase + DNA polymerase probe / electrophoresis for identification PCR to amplify DNA restriction enzyme DNA ligase - to join desire gene + plasmid add promoter

Answer 17

add / insert correct dominant allele only need 1 allele to cure disease synthesise correct functional protein no need to remove faulty allele

Answer 18

obtain normal, dominant allele insert allele into AAV virus as vector remove stem cells / T-lymphocytes insert allele into stem cells / T-lymphocytes return cells to body by injection

Answer 19

can insert healthy allele randomly into host DNA may cause cancer inserted allele may be inactivated virus may not enter target cells

Answer 20

- must be injected into target cell - low efficiency of cellular uptake - rapidly broken down

Answer 21

- small packaging capacity - only small amt of DNA carried - low probability of integration into host genome - cause mutations in host DNA

Answer 22

- low ability to add DNA into target cells

Answer 23

embryos may be destroyed wrong for parents to choose - designer babies contrary to beliefs/values less chance of HTT being passed on people with faulty allele who otherwise would not have children can now do so

Answer 24

potential side effects that could cause death germline gene therapy - causes modification to be passed on to future generations commercial viability for pharmaceutical companies: if it is a rare disease, the relative small number of patients may not mean that the companies will make a profit expense of treatments as multiple injections of the genes may be required if the somatic cells are short-lived possibility that people will become less accepting of disabilities as they become less common Who has the right to determine which genes can be altered and which cannot

Answer 25

taking preventative measures - elective mastectomy Using pre-implantation genetic diagnosis to select embryos that do not carry faulty disease - designer babies risk of miscarriage due to procedures used to collect DNA Choosing to terminate a pregnancy because the embryo has a genetic disorder make informed reproductive decisions possibility of stigmatisation and discrimination

Answer 26

obtain normal allele from mRNA by producing ss cDNA from mRNA using reverse transcriptase DNA polymerase to produce ds DNA restriction enzyme use vector on zygote add promoter add marker gene cloning/embryo splitting

Answer 27

gene for growth hormone inserted promoter from another species also inserted growth hormone produced all year round GM salmon grow faster and larger increase salmon yield growth hormone gene + promoter gene promoter gene ensured growth hormone continually being expressed To prevent the GM salmon from reproducing in the wild, all the salmon are female and sterile

Answer 28

allows farmers to spray a herbicide on the crop after germination to kill weeds that would otherwise compete with the growing soybeans for light, water and minerals resistant gene comes from Agrobacterium gene allows an enzyme in the soybean to continue to synthesise 3 AA needed to produce proteins required in the growing tips of plants herbicide glyphosate inhibits the enzyme in plants without the resistant gene; without the proteins being synthesised, the plants die

Answer 29

insect is killed by the herbicide/insecticide reduces competition manually spraying insecticide/herbicide is difficult + expensive

Answer 30

Bt toxin gene obtained from Bacillus thuringiensis restriction enzyme amplify gene using PCR insert gene into plasmid add promoter seal plasmid using DNA ligase forms recombinant DNA cotton cell takes up plasmid expresses new gene - Bt toxin gene transcribed

Answer 31

Bt toxin only kills specific insects reduce use of insecticides - less costs to farmers

Answer 32

Insect populations have developed resistance to the genes for Bt toxin, reducing its effectiveness resistance may be transferred to wild plants contamination of food marketed as organic may kill pollinators/beneficial insects decrease in biodiversity potential health risks for humans

Answer 33

possible side effects/allergy - may not be pure process may harm goats - animal welfare

Answer 34

GM production cost is expensive - only 1% success monopoly held by MNCs people may avoid/refuse to buy GM food no long-term studies done on effects on human health - unknown health consequences possible allergic reactions/immune response/side effects more food supply GM crops decrease food cost increase country's wealth relieve hunger / starvation reduce land area for crops - protect biodiversity less insecticides used less money spent on insecticides high cost of GM seed decrease in genetic variation

Answer 35

increase yield increased quality improvement to health longer shelf-life some GM crops are adapted to unfavourable conditions less cost on insecticides consumer resistance possible allergen/side effects expensive may have to buy seeds every season contaminate food labelled as organic