MCAT - Lab Techniques (MilesDown) fully solved

MCAT - Lab Techniques (MilesDown) Native-PAGE - correct answer A polyacrylamide gel electrophoresis method for proteins using NON-DENATURING conditions. Proteins keep their native charge and structure so they are separated based on charge and size. SDS-PAGE - correct answer A polyacrylamide gel electrophoresis method for proteins using DENATURING conditions. Sodium Dodecyl Sulfate denatures the proteins and gives the proteins a uniform charge. This allows them to be separated solely on mass, thus, you can estimate the protein's molecular mass. Reducing SDS-PAGE - correct answer Exactly the same as SDS-PAGE, but with the addition of a reducing agent, b-mercaptoethanol, which will reduce the disulfide bridges and result in a completely denatured protein. Isoelectric Focusing - correct answer basis of their relative contents of acidic and basic residues. The gel has a pH gradient and the proteins will migrate through the gel until they reach the pH that matches their isoelectric point. At the pI, the protein has a neutral charge, so it will no longer be attracted to the anode and it will stop migrating. Blotting techniques - correct answer Southern Blotting: Detection of a specific DNA sequence in a sample. Northern Blotting: Detection of a specific RNA sequence in a sample. Western Blotting: Detection of a specific PROTEIN in a sample. SNOW-DROP Chromatography - correct answer Stationary Phase: Typically polar. Polar molecules elute slower.