Mcat Lab Techniques Study Guide Graded A+

X-ray crystallography {Ans: -to visualize the structure of a molecule used often with proteins -a crystalline molecule causes a beam of incident x rays to diffract into many specific directions -a 3 dimensional image can be constructed by measuring the different angles and intensities of the diffracted rays}southern blotting {Ans: -detection of a specific DNA (Southern blot) -step 1: the DNA strand of interest is exposed to restriction enzymes that cut the DNA strain into smaller fragments -step 2: the newly cleaved strands of DNA are denatured using a solution of NaOH to create ssDNA strands -step 3: the single stranded cleaved strands of DNA undergo gel electrophoresis, separating them by size. smaller fragments will be found at the bottom of the gel. Polyacrylamide is used if the strands are less than 500 base pairs. Agarose is used if the strands are over 500 base pairs. -step 4: the DNA from the gel is transferred to a sheet of nitrocellulose paper and then exposed to a 32P radiolabeled DNA probe that is complementary to our DNA of interest -nitrocellulose paper is then viewed using autoradiography to identify the strand of interest}polymerase chain reaction {Ans: -used to amplify