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17 Cards in this Set
- Front
- Back
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What is the use of recombinant DNA technology? |
- allows genes to be manipulated/altered/transferred between organisms - understand how organisms work - design new industrial processes |
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How can recombinant DNA technology be used to cure human diseases? |
- due to inability to produce metabolic chemicals e.g insulin - prev. treatment=extract animal/human donor - problem with rejection by immune system - technique developed=isolate/clone/transfer genes to microorganisms - grown=factory for continuous production of desired protein |
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What is recombinant DNA? |
- two different organisms' DNA that have been combined - results in transgenic/genetically modified organism (GMO) |
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What are the applications of 'genetic engineering'? |
- producing insulin from bacteria - bananas with hepatitis B antigen (vaccine) |
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What is cloning? |
- making multiple genetically identical copies of a DNA molecules |
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What are the stages of making a protein using recombinant DNA technology? |
Isolation: of DNA fragments that have desired gene Insertion: DNA fragment into vector Transformation: transfer DNA into suitable host cell Identification: Find host cells that have taken up gene using gene markers Growth/Cloning: of host cells |
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What methods are there for producing DNA fragments for the isolation stage? |
- conversion of mRNA to cDNA using reverse transcriptase - using restriction endonucleases to cut out desired gene - create gene in machine based on known protein structure |
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How do you produce a DNA fragment using reverse transcriptase? |
- in host cell: reverse transcriptase catalyses production of cDNA from mRNA - single strand complementary DNA to double strand using DNA polymerase |
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What are the advantages of using cDNA in genetic engineering? |
- no introns to remove - specific unlike the genome - cells have large quantities of mRNA=easily extracted |
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What are restriction endonucleases? |
- bacteria freq. infected by viruses that inject DNA=take over cell
- produce enzymes that cut viral DNA=restriction endonucleases |
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How do you produce DNA fragments using restriction endonucleases? |
- each restriction enzyme cuts DNA at specific base sequences (recognition sites) - used to cut genes out from DNA molecule - cut straight (blunt) or staggered=single strand of DNA bases (sticky) - same restriction enzyme cuts gene/open vector DNA=sticky ends complementary |
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What are ligase enzymes? |
- joins backbone of two strands of DNA together - if DNA has sticky ends=must be complementary |
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What are oligonucleotides? |
- short single stranded DNA molecules |
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How do you produce DNA fragments using the gene machine (synthesising genes chemically)? |
- base sequence of desired gene from protein - sequence fed into a computer - checked for biosafety - computer designs oligonucleotides=assembled to desired gene - PCR makes complementary strand of nucleotides to make double stranded gene - use sticky ends=gene inserted to plasmid=vector for cloning - gene checked and errors rejected |
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How are oligonucleotides assembled into a gene? |
- oligonucleotides assembled by adding one nucleotide at a time in required order - oligonucleotides joined to make gene (no introns) - replicated with PCR |
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What are the advantages of using the gene machine to make DNA fragments? |
- easy - make any DNA sequence - no introns |
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What are the disadvantages of using the gene machine to make DNA fragments? |
- expensive - needs careful checking for errors |
