The “.doc” extension is typically used for: ((MCAER 2014))

✅Explanation: Electrophoresis is a technique used to separate charged molecules based on their movement in an electric field. The rate at which a molecule moves depends on its charge, with positively charged molecules moving towards the negative electrode and negatively charged molecules moving towards the positive electrode.  

🔑Key Points:
-Electrophoresis is a method of separation on the basis of the charge to mass ratio of macromolecules under the influence of an electric field. 
-Many important biological molecules such as nucleotides, DNA, RNA, peptides and proteins bear ionisable groups, and therefore at any given pH exist in solution as electrically charged species either as cations or anions.
-Under the influence of an electric field, these particles will migrate either towards cathode or anode, depending on their net charge.
-The mobility of a molecule is inversely proportional to its size and directly proportional to its charge, allowing them to be separated from one another.
-There are two types of Electrophoresis – Agarose Gel Electrophoresis & Polyacrylamide Gel Electrophoresis (PAGE).
-Polyacrylamide Gel Electrophoresis (PAGE) is an analytical method used to separate components of a protein or nucleic acid mixture based on their size i.e molecular mass.
Working of PAGE –
-To provide a uniform charge to the protein molecules, an anionic detergent called sodium dodecyl sulfate (SDS) is used to bind the proteins and give them a negative charge.
-Proteins are then separated electrophoretically according to their size using a gel matrix made of polyacrylamide in an electric field.
-Polyacrylamide is produced as a result of the polymerisation reaction between acrylamide and N, N' methylene-bis-acrylamide (BIS) using a catalyst.
-The degree of polymerisation or cross-linking can be controlled by adjusting the concentration of acrylamide and BIS.
-The more the cross-linking the harder the gel. The hardness of the gel, in turn, modulates the friction experienced by macromolecules when they travel through the gel during PAGE, thus affecting the resolution of separation.
-Loose gels (4–8% acrylamide) allow higher molecular weight molecules to migrate faster through the gel while hard gels (12–20% acrylamide) restrict the migration of large molecules and selectively allow small ones to move through the gel.