ch. 19 Genetic Technologies Flashcards
what is used when many copies of DN are required for testing?
polymerase chain reaction (PCR)
what does PCR require?
target DNA, lab-made primers which are complementary to the target sequence, nucleotides, Taq polymerase from Thermus aquaticus
what is Taq?
thermophila, found in hot springs, function best at a very high temp
what does heat do?
separates strands of target DNA, primers attach to target sequence, Taq polymerase adds nucleotides to target
what is exponential amplification?
doubling with each cycle, usually requires at least 20 cycles
What if you have RNA, but not DNA?
need to do reverse transcription to go from RNA to DNA; makes a compliementary DNA strand (cDNA) which then can be used for amplification of the gene
what is southern blotting?
used to detect particular gene within DNA, provides info about # of copies of type of gene, identify homologous genes (sim but not identical), denture DNA run through gel electrophoresis transfer to membrane with a radiolabeled probe
what charge does DNA have?
negative so top of gel negative and bottom positive so DNA drawn to gel
What if southern blotting shows that the gene is there?
it may or may not show up on the northern blot. the protein may or may not show up on the western blot
what is the western blot?
need to make an antibody that will recognize the protein a secondary antibody will recognize primary antibody and has dye on it.
what is the last step of a western blot?
add aklaline phosphatase which pulls off of secondary antibody, which creates a color change (usually gray or black)
t/f secondary antibodies are much less specific, bind to almost any primary antibody, so cheaper to make
true
t/f restriction enzymes bind DNA at specific points and looks for symmetrical strands?
false- breaks
In DNA sequencing what is dideoxyribonucleotides (ddNTPs)?
missing hydroxyl group from the 3’ carbon, ddATP, ddTTP, ddCTP, ddGTP
what happens if there is no hydroxyl group?
polymerase will stop causing termination of growing chain of DNA.