What is differences between agar and agarose?

Answer 1

Agarose is made from agarose, a polysaccharide from see weeds. Polyacrylamide is made from the synthetic polymerization of acrylamide, which in its monomeric form is a neurotoxin. Based on these structural differences, it could be said that agarose gels have larger 'pores' than polyacrylamide gels meaning that large particles can move more easily in agarose gels since the agarose polymers are larger and pack less densely then an equivalent amount of polyacrylamide. Therefore, agarose is generally used for the electrophoresis of large molecules such as DNA and RNA or speedy separation (low resolution) of small molecules such as proteins. Polyacrylamide is used for the high resolution electrophoresis of small molecules such as proteins.

Answer 2

Agar is a heterogeneous mixture of two classes of polysaccharide: agaropectin and agarose. Although both polysaccharide classes share the same galactose-based backbone, agaropectin is heavily modified with acidic side-groups, such as sulfate and pyruvate. The neutral charge and lower degree of chemical complexity of agarose make it less likely to interact with biomolecules, such as proteins. Gels made from purified agarose have a relatively large pore size, making them useful for size-separation of large molecules, such as proteins or protein complexes >200 kilodaltons, or DNA fragments >100 basepairs.

Agarose is purified from the polysaccharide complex, agar. This purified fraction forms a neutral gel matrix that is commonly used in gel electrophoresis. We have found that for many routine uses, agar which is considerably less expensive than agarose can be used with satisfactory results.