DNA technology Flashcards
what does denature mean?
to separate the two strands of DNA double helix.
what is the temperature needed to separate the DNA strands called?
melting temperature or Tm
Denatured DNA is…
less viscous, is denser, and more able to absorb UV
Separated strands will spont associate with their original
partner or any other complementary nucleotide sequence. Therefore, following double stranded combos can be formed through nucleic acid hybridization
DNA-DNA
DNA-RNA
RNA-RNA
methylation
bacteria methylate their DNA to protect it form viruses. methylation is not always but usually associated with inactivated genes.
what are restriction enzymes?
also called restriction endonuclease digest or cut nucleic acids at certain sequences. - such a sequence is called restriction site. typically a restriction site will be a palindromic sequence 4-6 nucleotides long . palindromic means it reads the same backwards or forwards.
what is recombinant DNA
DNA that is artificially recombined.
what is cDNA?
Its DNA that’s reverse transcribed from mRNA. but the great thing about cDNA is that it lacks introns that would normally be found in eukaryotic DNA.
What is PCR?
POLYMERASE chain reaction ! - exponential increase in the DNA .PCR requires that the base sequence of flanking the ends of the DNA fragments be known, so that the complementary primers can be chosen.
what is southern blotting?
technique used to identify target fragments of known DNA sequence in a large population of DNA. DNA to be identified is cleaved into restriction fragments . fragments are separated according to size by gel electrophoresis. large fragments move slower then smaller fragments. next gel is made alkaline to denature DNA . a membrane , like sheet of nitrocellulose is used to blot gel which transfers the resolved single stranded DNA fragments onto the membrane . a radio labeled probe with a nucleotide sequence complementary to target fragment is added to mem. the probe will hybridize with and marks the target. the membrane is exposed to radiographic film which reveals location of probe and the target fragment. `
what is a northern blot?
same as southern blot but it identifies RNA fragments
what is a western blot?
can detect particular protein in mixture of proteins. proteins are first resolved by size using gel electrophoresis. next they are blotted using nitrocellulose membrane. an antibody specific to the protein in question is then added and binds to the protein. then a secondary antibody enzyme conjugate is added. the secondary antibodies will bind to the primary antibody and marks it with enzyme for visualization.
so basically you detect protein with antibodies.
what are restriction fragment length polymorphisms?
RFLP identifies individuals . DNA of different individuals possesses different restriction sites and varying distances between restriction sites.
