Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

bio component 2 > applications of genetics > Flashcards

applications of genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

what were the aims of the human genome project?

A
  • determination of order of bases in human genome
  • identification of genes
  • mapping of positions of genes on chromosomes
  • anonymous (but still concerns)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what were the findings of the human genome project?

A
  • fewer genes in human genome than expected
  • more repeated segments in DNA than expected
  • there is a very close relationship linking all living organisms
  • enabled embryo screening and screening for adult-onset disorders (cancers, huntington’s, alzheimer’s, cystic fibrosis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what were the aims of the 100K genome project?

A
  • sequencing genomes of 100,000 NHS patients
  • not anonymous (concerns that come with this)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what were the findings of the 100K project?

A
  • improved accuracy of diagnosis
  • enabled tailoring of treatments and better predictions of effects of drugs
  • improved study of variation with human genome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the ethical concerns with finding out results of genetic screening?

A
  • embryo screening may provoke idea of choosing alleles to ensure specific characteristics of child
  • debate when a condition becomes a characteristic
  • discrimination/ social stigmatism
  • who has ownership and/or access to genetic data
  • effect on loved ones
  • misuse of data (eg. hacking)
  • lab errors leading to misidentification
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

which methods of sequencing were used for the two genome projects?

A
  • HGP: sanger sequencing (took long time, only sequenced short sections of DNA)
  • 100K: next generation sequencing (sequences entire human genome in few hours)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

why may genetic counselling be needed when going through screening process?

A
  • to make sure the patient is informed of all risks before making decision
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what other genome projects have been carried out?

A
  • chimpanzee’s
  • allows conclusions to be drawn about evolutionary relationships by examination of genomes
  • may help with conservation of species in future
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

why was the vector (mosquito) genome sequenced in attempt to find methods of controlling spread of malaria?

A
  • mosquitoes keep becoming increasingly resistant to insecticides
  • sequencing of genome allows scientists to develop chemicals that make them susceptible to chemicals again
  • which therefore prevents transmission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

why was the parasite (plasmodium) genome sequenced when attempting to find methods of controlling malaria?

A
  • parasite keeps developing multi-drug resistance
  • sequencing allows development of more effective drugs (eg. quinine- disrupts parasites digestion of haemoglobin)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are stem cells?

A

undifferentiated cells that can divide to give rise to cells which can then differentiate into specialised cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the two types of stem cells?

A
  1. embryonic stem cells (ESC’s)
  2. induced pluripotent stem cells (iPSC’s)
    - prefer 2. over 1. as fewer ethical issues and less chance of rejection as cells are coming from self
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the pro’s of stem cell usage?

A
  • production is large-scale and quick
  • produces genetically identical cells
  • ESC’s can become any cell
  • helps with lack of transplant
  • large potential benefit
  • ESC’s can clarify fundamental biological mechanisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the cons of stem cell usage?

A
  • expensive and unreliable
  • still a new science- unforeseen consequences
  • inadvertant selection of disadvantageous alleles
  • embryo has moral rights
  • ESC’s not really justified as have other option
  • may lead to human cloning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is gene therapy?

A

the treatment of a genetic disease by inserting a functional DNA sequence into the cells of someone who has defective alleles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the two methods of gene therapy?

A
  1. somatic cell gene therapy
  2. germ-line gene therapy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is somatic cell gene therapy?

A
  • replace faulty genes with correct copies in affected tissues of body (lungs, gut, reproductive organs)
  • new gene can’t be inherited as only placed in somatic cells
  • therefore can still pass condition onto children
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is germ-line gene therapy?

A
  • gene would be inserted into embryo or gametes
  • all new cells formed would now contain new gene
  • correction is inherited (more controversial)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the pros of somatic cell gene therapy?

A
  • relief of symptoms
  • no need for medication
  • prevents development of cancer
  • doesn’t permanently change genome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the cons of somatic cell gene therapy?

A
  • more than one treatment required
  • difficult to get gene to integrate into chromosome and function correctly
  • genetic disorder can still be passed onto offspring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are the pros of germ-line gene therapy?

A
  • children would be free of genetic disorder
22
Q

what are the cons of germ-line gene therapy?

A
  • fear that it could be used to modify characteristics of child
  • permanent modification= ethical issues
23
Q

what is DMD?

A
  • Duchenne Muscular Dystrophy
  • recessive
  • sex-linked
  • no cure- treatments available (drisapersen)
  • caused by a deletion which introduces stop codon too soon, causing lack of structural protein dystrophin
  • leading to wasting of muscles
24
Q

how does drisapersen work in treating DMD?

A
  • complementary to mutated sequences
  • uses exon skipping to acts as a ‘molecular patch’
  • binds to mRNA, over exon with deletion
  • makes it readable again as ribosome can’t translate it
  • results in shorter, but more functional dystrophin
25
Q

what is meant by the term ‘transgenic’?

A

-organisms which contain DNA from another organism

26
Q

what is meant by the term ‘recombinant DNA’

A

when the DNA of an organism is formed from different organisms

27
Q

summarise the process of genetic engineering

A
  • isolation of gene in a DNA fragment
  • insert DNA fragment into vector (plasmid of bacterium)
  • transfer of DNA to suitable host cell
  • identification of host cell that have taken up gene (gene markers)
  • growth/cloning of transformed host cells
28
Q

what should you do beforehand with the bacteria?

A
  • treat with chemicals to destabilise cell walls
29
Q

what is the role of restriction endonucleases?

A
  • bacterial enzymes that cut DNA at short, specific and palindromic sequences
  • isolates and cuts gene from a chromosome
  • unpaired bases produce sticky ends as enzymes make staggered cut
  • same enzyme also cuts and produces complementary sticky ends in plasmid DNA
30
Q

what are the problems with using restriction endonucleases?

A
  • hard to locate gene
  • recognition sequence could happen to also be in the middle (as well as end) of gene- cuts at inappropriate point
  • DNA contains many introns that bacteria can’t recognise/cut- protein translated will have extra amino acids and may not be functional
31
Q

what can be done before cutting the DNA from a chromosome to make the gene more functional when transferred into host cell?

A
  • collect mRNA for the desired gene (at this point introns have been removed)
  • convert mRNA into cDNA (copy DNA) using enzyme reverse transcriptase
  • then use DNA polymerase to convert cNA to dsDNA (double-stranded DNA)
  • this is then put into plasmid
32
Q

why should we use reverse transcriptase for isolation of a gene?

A
  • don’t have problems of introns (cDNA is made from mRNA- has already been transcripted in nucleus and spliced)
  • easier to locate gene
  • gene won’t be cut into non-functional fragments
  • no need for post-transcriptional processing
33
Q

how do we increase the chances of a bacteria taking up the recombinant plasmid?

A
  • heat shock
  • cool to 4oC
  • quick heat to 42oC
34
Q

what are the 3 possible results when transferring the recombinant plasmid to growing culture of bacteria?

A
  1. no plasmid taken up
  2. non-recombinant plasmid (where DNA ligase has just joined the plasmid back together)
  3. recombinant plasmid
35
Q

explain the use of genetic markers in identifying bacteria that take up the recombinant plasmid

A
  • plasmids with genes for antibiotic resistance are used (ampicillin and tetracycline)
  • back in first steps, use restriction endonuclease with recognition site in middle of tetracycline resistance gene
  • therefore, tetracycline resistance gene will no longer work if recombinant plasmid is taken up
36
Q

describe the experiment carried out using genetic markers

A
  • have a master (control) plate with no antibiotics present
  • transfer bacteria with sterile velvet (replica plating) to plate with ampicillin
  • transfer to 3rd plate with tetracycline
  • go back to master plate and collect wanted colonies (as colonies are in same positions on plate)
37
Q

explain the results of the genetic markers experiment

A
  • control plate shows all three types of bacteria
  • ampicillin shows bacteria with recombinant and non-recombinant plasmid (ones without plasmid killed)
  • tetracycline plate only shows non-recombinant plasmid (recombinant ones are killed as tetracycline resistance gene is non-functional)
  • colonies that were on the ampicillin plate but not the tetracycline plate are collected
38
Q

what is scaling up?

A
  • growing desired colonies in a fermenter
39
Q

what are the pros of recombinant DNA technology?

A
  • large-scale production of complex proteins- no limit to amount produced
  • no need to use extracts from mammalian organs
40
Q

what are the cons of recombinant DNA technology?

A
  • complicated so needs experienced staff and equipment
  • £££
  • synthesis of required protein may involve several genes which each code for a polypeptide
  • treatment with restriction endos produces millions of fragments that cant be used
  • not all eukaryotic genes can be expressed in prokaryotic cells
41
Q

what are the concerns that come with recombinant DNA technology?

A

possible transfer of antibiotic resistance gene to human pathogens (due to ready exchange of genetic material between bacteria)

42
Q

what is genetic modification used for?

A
  • certain species of bacteria naturally attack damaged plants and stimulate growth of tumor
  • scientists can replace tumor with useful genes
43
Q

how are genetically modified crops produced?

A
  • using technique to make GM bacterium (reverse transcriptase/ restriction endos)
  • causes plants to form clumps of undifferentiated cells (stem cells)
  • stem cells used to grow new plants
44
Q

give 2 examples of GM crops

A
  • tomatoes
  • soya
45
Q

what are benefits of GM crops?

A
  • superior keeping qualities
  • higher yield
  • reduction in pesticide use (for ones engineered for resistance anyway)
46
Q

what are the concerns that come with GM crops?

A
  • reduction in biodiversity
  • GM crops may be resistant to herbicides (eg. soybean)
  • unknown effects of eating new proteins produced by crop
47
Q

where can DNA profiling be used?

A
  • human paternity testing
  • forensic science
48
Q

what are STR’s?

A
  • short tandem repeats
  • blocks of repeated nucleotides in introns
  • varied in length and are repeated different no.s of times (leads to variation)
  • no. of STR’s used to build unique fingerprint
49
Q

what is an example of a STR?

A
  • D7S280
  • ‘GATA’ bases are repeated on human chromosome 7
  • different alleles of this locus have between 6-15 repeats of ‘GATA’
  • more times repeated= longer DNA fragment
50
Q

describe the method used in genetic fingerprinting

A

bio component 2 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions