manipulating genomes Flashcards
Explain how the automated sequencing machine orders the DNA fragments from the PCR
electrophoresis ;
(negatively-charged DNA) moves towards ,
positive electrode / anode ;
smallest/smaller (fragments) move, fastest / faster ; ora
resolution on gel sufficient to register 1, nucleotide /
base;
It is proposed that a simple saliva test could identify those children who have the mutation.
What would be the source of the genetic material used in this test?
(epithelial) cells lining cheek
Name the enzyme that can be used to convert mRNA to single-stranded DNA.
reverse transcriptase
Explain how the locations of the fluorescent spots on the DNA chip reveal which genes are most active.
1 mRNA binds to , (gene) probes / cDNA / ssDNA ,
by complementary base pairing ;
2 idea that the more active the gene
the more mRNA produced ;
3 during transcription ;
4 more fluorescence indicates more mRNA (bound) ;
Outline the roles of each of the following procedures in sequencing a genome:
the polymerase chain reaction (PCR)
to, amplify / make (many) copies of, DNA ;
(range of) different lengths ;
Outline the roles of each of the following procedures in sequencing a genome:
electrophoresis
to put DNA pieces in size order ;
to read, base sequence / order of bases ;
Outline the roles of each of the following procedures in sequencing a genome:
restriction enzymes
to cut (genome DNA) into, small(er) / 750 bp, fragments ; to cut, vectors / BACs / plasmids, (for gene library) ;
Suggest why a genome has to be fragmented before sequencing.
genome, too big / very large ;
accuracy better / fewer errors (with small fragments) ;
divide job over, time / different labs ;
Explain why injecting recombinant HGH in this way is not an example of gene therapy.
1 (child’s) cells / DNA / genes / alleles ,
not changed ;
2 vector not used (in child) ;
3 child / cells , not producing , HGH / hormone ;
4 HGH / drug / injection ,
has to be given repeatedly /
is a short term solution / not a cure ;
Name the process that:
has given rise to the modern domestic cat from its wild ancestor
has given rise to coat colour variation in cats.
selective breeding / artificial selection ;
(named type of) mutation / production of new alleles ;
sexual reproduction / meiosis / independent assortment /
crossing-over ;
Suggest why physiological problems are more common in pedigree animals.
1 inbreeding / small or decreasing, gene pool ;
2 homozygous recessive (genotypes) ;
3 gene / allele , for desired characteristic on same
chromosome as problem, gene / allele ;
4 selecting for one trait (unintentionally) selects for another ;
5 breeders select for looks not health ;
6 weaker selection against less healthy animals (than in wild) ;
Define the term recombinant DNA.
DNA (combined) from (two) , sources / organisms ;
Suggest why the Hardy-Weinberg principle cannot be used to predict the expected frequencies of albino and non-albino alleles in the worldwide zoo population of tigers.
population, not large / (too) small ;
not randomly-mating / matings arranged ;
List two factors that might cause allele frequencies to change from generation to generation in a population that meets the Hardy-Weinberg criteria.
natural / artificial / directional, selection ;
genetic drift ;
mutation ;
migration / AW ;
Discuss the potential benefits to mankind and the ethical concerns raised by the following examples of genetically modified organisms:
• rice modified for increased vitamin A content (‘Golden Rice™’)
• humans having somatic gene therapy treatment for a genetic disease.
In your answer you should give a balanced account of the benefits and concerns for each example of genetic modification.
‘Golden RiceTM‘
B1 reduce vitamin (A) deficiency in named area / ora ;
B2 reduce, eye problems / blindness ;
C1 reduce rice genetic, diversity / variation ;
C2 clone may suffer from one, disease / environmental change ;
C3 hybridisation with wild rice / spread genes to wild populations ;
C4 seeds expensive / need to be bought each year ;
C5 rice may not grow in all areas where needed ;
C6 idea of doubts whether vitamin A content sufficient ; 4 max
Somatic Gene Therapy
B3 cure / reduce symptoms / better quality of life / less medication;
B4 cystic fibrosis / SCID / Parkinson’s / thalassaemia / LCA ;
B5 extend lifespan / saves lives ;
C7 virus vector may cause (viral) disease ;
C8 procedure may be, invasive / dangerous / painful / stressful ;
C9 temporary / needs to be repeated / limited success ;
C10 immune system / rejection, problems ;
C11 animal testing concerns ; 4 max
Either Section
C12 antibiotic resistance gene transfer to pathogenic bacteria ;
C13 unknown effects / cause mutation ;
State the name given to the process in which only a certain percentage of adult foxes were chosen by humans to breed in each generation.
artificial selection / selective breeding ;
Suggest why 20% of the female foxes were used for breeding but only 5% of the male foxes.
idea that males can father many offspring / mate several females ;
idea that females produce only a few offspring ;
(so) more females (than males) needed to
maintain numbers (each generation) ;
(20% females chosen as) inbreeding / genetic problems,
if breeding population is too small ;
(5% males chosen as) selection pressure stronger
if fewer (tamest) are used ;
suggest about the causes of the variation in tameness behaviour in silver foxes.
1 (mostly) genetic ; 2 as can be selected for / selective breeding increases frequency ; 3 allele(s) for tameness ; 4 (from) mutation ; 5 query role of environment / learning ;
linkage
epistasis
inbreeding
genetic drift
linkage
tameness genes and genes for these traits on same
chromosome ;
(so) inherited together ;
epistasis
(product of) one gene affects expression of another ;
via enzyme pathway ;
inbreeding
(hidden / masked) recessive alleles ;
selected for, as well / unintentionally ;
more chance homozygous as, small gene pool / parents related ;
genetic drift
random / chance (which alleles, present / passed on) ;
(effect stronger because) small breeding population ;
Why is the continued existence of rare breeds of farm animals desirable?
1 genetic resource / gene bank / have (different) alleles ;
2 for , genetic engineering / genetic modification /
artificial selection / selective breeding / described ;
3 if conditions change / in the future ;
4 example of useful trait ;
5 to maintain , biodiversity / genetic diversity /
(large) gene pool ;
Suggest a technique that could be used to provide molecular evidence that all English Elm trees form a clone.
DNA / gene / genetic , fingerprinting / profiling / analysis ;
DNA / protein / gene , sequencing ;
electrophoresis ;
Describe the differences between:
somatic cell gene therapy and germ line cell gene therapy
somatic changes / uses , body cells ; change cannot be passed to offspring ; cures / alleviates , genetic disease in one individual ; short-lived / repeat treatments needed ; germ line changes / uses , gametes / zygote / embryo / reproductive tissue ; banned ;
Explain why there was such a rapid loss of elm trees in Britain as a result of this elm disease.
1 genetic resource / gene bank / have (different) alleles ;
2 for , genetic engineering / genetic modification /
artificial selection / selective breeding / described ;
3 if conditions change / in the future ;
4 example of useful trait ;
5 to maintain , biodiversity / genetic diversity /
(large) gene pool ;
State three phenotypic traits (characteristics) that have been selected for in dairy cows.
idea that (produces)
large , yield / volume / amount, of milk ;
idea of long lactation period ;
idea of high milk quality ;
large udders /
correct udder shape (for milking machine) ;
resistance to , (named) disease / mastitis / pathogens
or
effective immune system ;
idea of calm temperament ;
Suggest why monkeys rather than other laboratory animals, such as rats, were used for this work and comment on whether their use in this way is justified or not.
monkeys rather than rats idea that (humans & monkeys) closely related / share more genes / share a common ancestor ; (humans & monkeys) both primates ; idea that brain / body , structure / physiology / behaviour , similar (to humans) ; monkey brain bigger (than rat) ; max 2 comment argument in favour ; argument against ;
Suggest two characteristics that researchers should look for when choosing an organism for research into how genes control development.
small ; short life cycle ; easy to, keep / breed / AW ; cheap (to buy / keep ) ; readily available / common / not rare ; large cells ; previously well-studied / many known mutants ;
