Genetics

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  • Created by: syaqub18
  • Created on: 10-06-15 13:16
What are the three different ways DNA fragments can be made?
Reverse transcriptase, PCR chain reaction, restriction endonuclease
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How can Reverse transcriptase be used to make DNA fragments?
Enzyme reverse transcriptase makes DNA and RNA template, the DNA made is called complementary DNA (cDNA), mRNA is isolated from cells, mixed with free nucleotides and enzyme, enzyme uses mRNA as a template
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How can the polymerase chain reaction (PCR) be used to make DNA fragments?
Mixture contains DNA sample, free nucleotides, primers and DNA polymerase, mixture heated to 95C to break hydrogen and separate strands then cooled to 50C to let primers anneal/bind, mixture heated to 72 so DNA polymerase can work
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Where is the DNA polymerase used in PCR from?
From DNA of bacteria from hot springs
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How can restriction endonuclease enzymes be used to make DNA fragments?
DNA have palindromic sequences, restriction endonuclease recognise specific palindromic sequences, they cut at these sites as they are complementary to active site, cut leaves sticky ends, DNA with complementary sequences can join to sticky end
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What is in vitro gene cloning?
When gene copies made outside an organism
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What is in vivo gene cloning?
What is in vivo gene cloning?
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What is recombinant DNA?
DNA formed from joining DNA from different sources
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What is a vector?
Something that is used to transfer DNA to a cell
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How is recombinant DNA made?
Vector DNA isolated, its cut open by same restriction endonuclease used to isolate DNA fragment with target gene so sticky ends are complimentary, Vector and DNA fragment mixed with DNA ligase which joins them together (ligation)
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What does it mean when a cell is transformed?
When a host cell takes up the gene of interest
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How is bacteria encouraged to take up the recombinant DNA?
It is given an electric shock
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How is a bacteriophage vector?
A virus used to insert the recombinant DNA as it will infect the bacteria
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How are transformed cells identified?
Marker genes also inserted in to the vector, host cells grown on agar plate, marker gene can code for antibiotic resistance so the ones which do not have marker gene will die when treated with antibiotic, can use UV gene transformed cells fluoresce
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What are the advantages of in vivo cloning?
Produce mRNA and protein as well as DNA as done in living cell, can produce modified DNA, mRNA or proteins, larger fragments cloned, cheap depending on how much DNA is needed
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What are the disadvantages of in vivo cloning?
DNA has to be isolated from other cell components, you might not want modified DNA, can be slow as some bacteria grow slow
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What are the advantages of in vitro cloning?
Only can replicate small DNA fragments, can be expensive,
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What are the benefits of genetic engineering/transformed organisms in agriculture?
Agricultural crops can be transformed to give high yield or more nutrition to reduce famine and malnutrition, can be altered to be pest and drought resistant so reduces costs and environmental problems with chemicals
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What are the benefits of genetic engineering/transformed organisms in industry?
Often use enzymes, use enzymes from transformed organisms which means they can be produced in large quantities
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What are the benefits of genetic engineering/transformed organisms in medicine?
Many drugs made form recombinant DNA from transformed organisms, so medicines made can be made quickly and cheap to be available to more people
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What are the concerns of genetic engineering/transformed organisms in agriculture?
Monoculture could make crop vulnerable to disease because all plants identical, damage environment by reducing biodiversity, creating resistant weeds which could have a negative effect on environment
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What are the concerns of genetic engineering/transformed organisms in industry?
If labels do not have proper labelling, people won’t have a choice about whether to consume food from transformed organism, proteins from transformed organisms may introduce toxins
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What are the concerns of genetic engineering/transformed organisms in medicine?
Companies which one genetic engineering technologies may limit use of technologies saving lives, technology might be used unethically to produce designer babies
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What are the concerns of genetic engineering/transformed organisms globally?
A few large biotechnology companies control some forms of genetic engineering, use of technology makes these companies more powerful and force smaller businesses out of business
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What is genetic fingerprinting?
Looking at a specific loci on a genome normally non-coding, repetitive base sequences
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Why are repetitive base sequences used?
Because they differ from person to person and probability of having the same number of repeats is very low
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What are the steps of genetic finger printing?
1. PCR to make DNA fragments, 2. Separation of DNA fragments by gel electrophoresis 3. Analysis of the genetic fingerprints
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What occurs in the first stage of producing genetic finger prints (PCR to make DNA fragments)?
DNA taken from blood, saliva, etc. PCR used to make copies of DNA which contains repeated sequences, fluorescent tags added to the primers so they can be identified
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What happens in the second stage of producing genetic fingerprints (Separation of DNA fragments by gel electrophoresis)?
DNA placed in to a well in slab of gel and placed in buffer solution which conducts electricity, electrical current passed through gel, DNA fragments negatively charged so move away, shorter fragments move further
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What happens in the third stage of producing genetic fingerprints (Analysis of the genetic fingerprints)?
Gel placed under UV light, DNA fragments seen as fluorescent bands, bands make up finger print, compared against a ladder/DNA fragments of known length, compared if fragments in the same place it’s a match
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What are the uses of genetic finger printing?
Determining genetic relationships as maternal/paternal non-coding sequences are roughly the same, forensic science, medical diagnosis, animal and plant breeding
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How is a gene located using DNA probes?
sample of dna digested by restriction enzymes and seperated by electrophoresis, fragments transfered and incubated with fluorecently labelled DNA probe, if gene present probe will hybridise to it, then exposed to UV light
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what is restriction map?
a diagram of the piece of DNA showing the different cut sites and hence the recognition sites of the restriction enzymes
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what is DNA base seqeuncing?
determining the order of bases in a section of DNA
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what is the chain termination method?
a method of ordering basing in a section of DNA
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what is the mixture made up of in the four separate tubes in the chain termination method?
a single stranded DNA template which needs to be sequenced, DNA polymerase to join nucleotides, DNA primer, free nucleotides, fluorenscently labelled modified nucleotide (A*T*G*C*) each in a different tube
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what happens to the tubes in the chain termination method?
tubes undergo PCR, produces many strands, strands at different length as the modified nucleotide terminates it at a different point,
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what happens to the different lengths of DNA fragments produced in the chain termination method?
seperated by electrophoresis and visualised under UV light, reading from the top to bottom gives you the base sequence one at a time
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Other cards in this set

Card 2

Front

How can Reverse transcriptase be used to make DNA fragments?

Back

Enzyme reverse transcriptase makes DNA and RNA template, the DNA made is called complementary DNA (cDNA), mRNA is isolated from cells, mixed with free nucleotides and enzyme, enzyme uses mRNA as a template

Card 3

Front

How can the polymerase chain reaction (PCR) be used to make DNA fragments?

Back

Preview of the front of card 3

Card 4

Front

Where is the DNA polymerase used in PCR from?

Back

Preview of the front of card 4

Card 5

Front

How can restriction endonuclease enzymes be used to make DNA fragments?

Back

Preview of the front of card 5
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