8.4 Gene technologies

• recombinant DNA is when DNA from two different organisms is combined to create a new organism
• recombinant DNA technology involves the transfer of fragments of DNA from one organism/species into another
• what are the 5 steps to genetically modify an organism?

  identification, isolation, multiplication, transfer, identification
• in genetic modification how is the DNA fragment multiplied?

  polymerase chain reaction
• what are examples of possible vectors that are used when genetically modifying an organism?

  plasmids or viruses
• what enzymes are needed to genetically modify an organism?

  restriction endonucleases, ligase and reverse transcriptase
• how can a gene with specific characteristics that are wanted by obtained by scientists?

  extraction of gene using restriction endonucleases, mRNA and reverse transcriptase, using a gene machine
• restriction endonucleases are a class of enzymes found in bacteria that are used as a defense mechanism against bacteriophages
• sticky ends result in one strand of the DNA fragment being longer than the other strand, making it easier in insert the desired gene into another organisms's DNA as hydrogen bonds can form more easily
• a palindromic sequence of nucleotides is a sequence of nucleotides that is read in the same direction in both directions
• restriction endonucleases recognise specific palindromic sequences and cut the DNA at these places
• the polymerase chain reaction is an in vitro method of DNA amplification
• what is needed for each PCR reaction?

  target DNA or RNA, primers, DNA polymerase, Free nucleotides, buffer solution
• primers are short pieces of DNA that are complementary to the bases at the start of the fragment that you want
• what are the three stages of the PCR?

  denaturation, annealing, elogation/extension
• during denaturation in the PCR the double stranded DNA is heated to what temperature?

  95C
• annealing is the joining of two primers to their complementary bases at the end of the DNA fragment
• during the annealing stage of the PCR what temperature is used?

  50-60C
• during the elongation/extension stage of the PCR what temperature is used?

  72C
• each PCR reaction doubles the amount of DNA
• gene cloning can be carried out in vivo by using bacteria
• what are the 3 main stages of in vivo DNA amplification?

  DNA fragment inserted into a vector, the vector transfers the DNA fragment into host cells, transformed host cells are identified
• promoter regions are DNA sequences that tell the DNA polymerase when to start producing mRNA
• terminator regions tell the DNA polymerase when to stop producing mRNA