<prompt> In which type of Chromatography, the separation of Protein molecules is based on their size, shape and molecular weight?Partition chromatographyGel filtration chromatographyIon-exchange chromatographyAffinity chromatography  <response>: B Gel filtration chromatography Gel filtration chromatography: Separation of molecules is based on their size, shape and molecular weight. Technique is also referred to as molecular sieve or molecular exclusion chromatography. Apparatus consists of a column packed with sponge like gel beads usually cross-linked polysaccharides containing pores. Gels serve as molecular sieves for the separation of smaller and bigger molecules. Gel-filtration chromatography can be used for an approximate determination of molecular weights. This is done by using a calibrated column with substances of known molecular weight. Partition chromatography: Molecules of a mixture get partitioned between the stationary phase and mobile phase dependir g on their relative affinity to each one of the phases. Ion-exchange chromatography: Ion-exchange chromatography involves the separation of molecules on the basis of their electrical charges Ion-exchange resins--cation exchangers and anion exchangers--are used for this purpose. Affinity chromatography: The principle of affinity chromatography is based on the property of specific and non-covalent birding of proteins to other molecules, referred to as ligands. For instance, enzymes bind specifically to ligands such as substrates or cofactors. 