Topic 8 - genome project and gene technologies Flashcards
(47 cards)
1
Q
what is a genome
A
entire set of DNA
2
Q
what type of dna does gene sequencing work on
A
dna fragments
3
Q
what is the proteome
A
all the proteins that a cell can make
4
Q
what can sequencing the genome of organisms be used fir
A
- determine their proteins
- medical research - determine the shape of antigens to create a vaccine
5
Q
why is it harder to translate the genome of compelx organisms
A
- they contain large sections of non coding DNA
- also regulatory genes which determine when genes are turned on or off
- this makes it difficult as its hard to find the bits that code for proteins
6
Q
what are some features of new sequencing methods
A
- automated
- more cost effective
- done on a large scale
- faster
7
Q
what is recombinant DNA technology
A
- transfering fragments of DNA from one organism to another
- because the genetic code is universal and so are transcription and translation mechanisms
8
Q
how can DNA fragments be made using reverse transcriptase
A
- mRNA molecules are used as templates to make lots of DNA
- reverse transcriptase makes DNA from RNA template
- the DNA is called complimentray DNA
- mRNA is osilated from cells and mixed with free DNA nucleotides and reverse transcriptase
- the reverse transcriptase could be used to make complimentary DNA from the mRNA
- e.g. pancreatic cells produce insulin, they have lots of mRNA complimentray to the insulin gene but only 2 copies of the gene. so RT is used to make cDNA from the insulin mRNA
9
Q
How are DNA fragments made using restriction endonuclease enzymes
A
- some sections of DNA have palindromic sequences of nuecleotides.
- these consist of antiparallel base pars
- restriction endonucelases are enzymes that recognise specific palindromic sequences and cut the DNA at these places
- different enzymes cut at different recognition sequences due to the shape of the recognition sequence being complimentary to the enzymes actice site
- the dna sample is incubated with the specific enzyme which cuts the dna fragments out vua hydrolysis reaction
- sometumes the cut leaves sticky ends-unpaired bases at each end
- these can be used to bind the DNA fragments to another piece of DNA with sticky ends with a complimentary base sequence
10
Q
how can DNA fragments be made using a gene machine
A
- dna fragments can be synthesised from scratch by fixing a nuecleotide onto a solid support e.g. a bead
- nuceltoides are added in the correct order
- protecting groups are added to prevent branching
- oligonuceotides around 20 base pairs long are made
- the protecting groups are removed
- and multiple oligonucleotides can be joined to make longer fragment
11
Q
are sequencing methods continuously updated
A
yes
12
Q
what is in vitro
A
outside the cell
13
Q
what does PCR do
A
- polymerase chain reaction
- amplifies DNA samples
14
Q
what happens during the in vitro polymerase chain reaction
A
- a mixture of DNA sample, free nucleotides, primers and DNA polmerase is heated to 95degrees
- this breaks the hydrogen bonds between the DNA strands doubling the amount of DNA strands,
- The mixture is cooled to 55 degrees so the primers can bind to the strands
- the mixture is heated to 75 degrees so DNA polymerase can work (lines up nucleotides)
15
Q
what do primers do in PCR
A
- bind to the ends of the fragments
16
Q
what is a thermocycler
A
machine that controlls temperature at timed intervals
17
Q
when does polymerase chain reaction stop
A
- run out of nuceotides or primers
18
Q
what is in vivo
A
inside the cell
19
Q
what is the in vivo method for amplifying DNA
A
- promoter and terminator is added to the DNA
- The dna is inserted into a vector, e.g. plasmids from bacteria
- the vector dna is cut open using the same restriction enzyme that was used to isolate the DNA containing the wanted gene
- the sticky ends of vector dna and the dna fragment are complimentary
- the dna is combined using DNA ligase which joins the sticky ends of the dna together -ligation
- the new dna is called recombinent DNA and the bacteria has undergone transformation
20
Q
what is electoporation
A
- application of small electrical currents
- makes the membrane have small pores to allow the vector to enter the host cell
21
Q
what are marker genes
A
- for plasmids, antbiotic resistant genes can be inserted in the plasmid dna
- when the bacteria are grown on a medium containing that antibiotic, only the transformed cells with the new dna will grow
- for not in bacteria, a flourescence or enzyme that causes colour change can be inserted
- if it doesnt fluoresence or change the colour of the medium is tranformed
22
Q
what is recombinant DNA
A
- DNA that has been altered by introducing fragments from different sources, creating a new DNA sequence.
- can result in a new phenotype
- recombinant dna technology is the equipment used to transfer the dna
23
Q
why would recombinant dna technology be used in an egg cell
A
- all the body cells after mitosis will contain the desired gene
- offspring will have the gene
24
Q
how can recombinant dna technology be used to benefit agriculture
A
- crops can be transformed to give higher yeils or are more nutritioud, or are prest resistant
- this reduces chance of malnutrition
- reduces costs for pesticies
- reduces environmental problems associated with pesticides
25
how does recombinant dna technology benefit industry
* use enzymes from transformed organisms so they can be made in large quantities for less money
26
how can recombinant dna technology benefit medicine
* mant drugs and vaccines are made by transormed organisms
* can be made quickly and cheaply and in large quantity
27
what are concerns of using recombinant dna technology in agriculture
* farmmers might only plant one type of crop which can make them all vulnerable to disease
* also reduces biodiversity
* this can damage the environment
28
what are concerns of using recombinant dna technology in industry
* anti globalisation activists oppose globalisation
* use of technologies increases, the companies get more powerful and may force small companies out of business due to competition
29
what are concerns of using recombinant dna technology in medicine
* companies who own genetic engineering technologies may limit the use of technologies that could be saving lives
* some people worry this technology could be used unethically like to make designer babies
30
why do humanitarians think recombinant dna technology will benefit people
* crops can be produced that reduce risk of maluntrition and famine, e.g. drought resistant
* transformed crops can make pharmaceutical products like vaccines to make drugs available to more people
* medicines could be made more quickly and cheaply so people can afford them
* technology has the potential to be used in gene therapy to treat disease
31
what is gene therapy
altering the defective genes inside a cell to treat genetic disorders and cancer
32
how does gene therapy work if the gene defect is caused by 2 mutated recessive alleles
add a working dominant allele
33
how does gene therapy work if the gene defect is caused by a mutated dominant allele
you can silence the allele by sticking a bit of dna in the middle of the allale so it doesnt mwork anymore
34
in gene therapy how do you get the new allele in the cell
recombinant dna technology
35
what is somatic gene therapy
* altering the alleles in the body cells most affected by the disorder. the disease can still be inherited as sex cells arent changed
36
what is germ line gene therapy
* altering the alleles in sex cells so offspring dont get the disease
37
what are DNA probes used for
* locate specific alleles of genes
* or to see if a person has a mutated allele causing a disorder
38
what are DNA probes made of
* short single strands of DNA
* specific base sequence thats complimentray to the base sequnce of the target allele
* this means tha dna probe will bind to the allele if it is present
39
what is attached to a dna probe
* radioactive
* fluorescent
40
how is dna probing done
* restriction enzymes digest dna into fragments
* theyre separated by size mass or length or charge using electrophoresis
* theyre transfered to the nylon membrane and incubated with the dna probe
* if the allel is present it will bind and there will be flouresecence
41
what can screening using dna probs be used for
* identify inherited genes
* determine how patients will reposnd to drugs
* identify health risks
42
what is genetic councelling
* advising patients about the risks of genetic disorders
* telling them about screening and treatment available
43
what is personalised medicine
* different peoeple respond to drugs in different ways
44
what are VNTRs
* variable number of non coding tandems
* a sequence of bases repeated
* the number of repeats varies from person to person
* occurs in several places in the genome
* low probability of having the same non coding tandems
45
what is genetic fingerprinting
* comparing the number of times a sequence is repeated at different places in the genome between individuals
46
what is electrophoresis
* seprates dna fragments based on mass size length or charge
* smaller fragments travel further
47
what are some uses of genetic fingerprinting
* determining relationships between people
* determining genetic variation within a population
* forensic science - crime scene evidence (dna)]
* medical diagnosis
* prevent interbreeding of animals and plants
