The tighter the binding of a ligand to its receptor,the lower the concentration of ligand needed to achieve binding to 50 percent of the receptors.

#Id: 2477

#Unit 13. Methods in Biology

Agarose gels are formed  by suspending dry agarose in aqueous buffer, then boiling the mixture until a clear solution forms. 

#Id: 2478

#Unit 13. Methods in Biology

The most commonly used buffer for separating DNA is TRIS-acetate containing EDTA ( TAE) with a typical pH of 8.3 and used to dissolve the matrix (agarose) as well as the running buffer. 

#Id: 2479

#Unit 13. Methods in Biology

Separation of RNA, TRIS-borate with EDTA ( TBE) is typically used due to superior buffering capacity (beneficial for long run times).

#Id: 2480

#Unit 13. Methods in Biology

TBE gives superior separation of smaller fragments (< 2 kb) in comparison to TAE and is often used for separation of small RNA molecules such as microRNA.

#Id: 2481

#Unit 13. Methods in Biology

Polyacrylamide Gel are formed by the polymerization of acrylamide monomer in the presence of smaller amounts of N,N′-methylene-bis-acrylamide (normally referred to as ‘ bis-acrylamide’).

#Id: 2482

#Unit 13. Methods in Biology

The polymerization of acrylamide is an example of free-radical catalysis and is initiated by the addition of ammonium persulfate and the base N,N,N′,N′-tetramethylenediamine ( TEMED).