Question

Why are proteins heat denatured prior to analysis in SDS-PAGE? Select all answers that apply. Denaturation of the protein is necessary so that proteins run proportionally to their size, based on the interaction of SDS with the unfolded protein. Heat is used to hydrolyze the peptide bonds of the protein. The heat step allows the proteins to unfold, enabling the protein chain to be coated with SDS molecules. Heat is used to hydrolyze disulfide bonds. QUESTION 2 1.5 points Saved What mechanism will be used to lyse the bacterial cell membrane? Sonication/lysis by ultrasonic waves Glass beads /mechanicallysis French Press / Lysis by pressure Nonionic detergents / chemicallysis

Answer 1

Question 1 :

why are proteins heat denatured prior to analysis in SDS-PAGE

answer options a c and d.

The final factor in denaturing your protein is heat. Typically, you will boil your protein samples in the loading buffer (containing Tris-HCl, SDS, bromophenol blue, glycerol, and ?-me) before loading them in your gel. This helps to completely denature the proteins and also helps with physically loading the gel. Protein samples frequently are gummy, particularly if the protein prep is from cell or tissue extracts and therefore contains DNA. Boiling homogenates your sample, as the heat melts any DNA in the prep, in turn making it less gummy and easier to load on the gel. Heat also initiates redistribution of disulphide bonds of a protein

Question 2:

Mechanism used to lyse bacterial cell membrane is

answer option a sonication /lysis by ultrasonic waves.

Sonication is used to disrupt cellular membranes and release the cells contents, this process is generally referred to as sonoporation. ... Sonication of cells using a titanium probe can help lyse cells fully and help all extract all DNA, RNA and protein contents of your cells.

Question 3:

dyes used to visualize proteins in SDS -PAGE

answer is option a b and d.

Question 4 :

answer is option a anion exchange resin.

An ion-exchange resin or ion-exchange polymer is a resin or polymer that acts as a medium for ion exchange. It is an insoluble matrix (or support structure) normally in the form of small (0.25–0.5 mm radius) microbeads, usually white or yellowish, fabricated from an organic polymer substrate. The beads are typically porous, providing a large surface area on and inside them. The trapping of ions occurs along with the accompanying release of other ions, and thus the process is called ion exchange. There are multiple types of ion-exchange resin. Most commercial resins are made of polystyrene sulfonate. Ion-exchange resins are widely used in different separation, purification, and decontamination processes. The most common examples are water softening and water purification. In many cases ion-exchange resins were introduced in such processes as a more flexible alternative to the use of natural or artificial zeolites.

Question 5 :

answer is option b

Question 6:

purpose of beta mercaptoethanol (BME) :

answer is option a

BME is suitable for reducing protein disulfide bonds prior to polyacrylamide gel electrophoresis and is usually included in a sample buffer for SDS-PAGE at a concentration of 5%. Cleaving intermolecular (between subunits) disulfide bonds allows the subunits of a protein to separate independently on SDS-PAGE.