why do we use in electrophoresis agarose instead of agar?

Answer 1

Actually it is explained very well in wikipedia

"Agar is a heterogeneous mixture of two classes of polysaccharide: agaropectin and agarose [1]. 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 can be used for electrophoretic separation or for column-based gel filtration chromatography."

So agar (because of agaropectin) might interact with some biomolecules rendering separation a function not only of size but also chemical consistency. I guess it is also implied that agaropectin forms gels with pores of too small size to allow separation of biomolecules.

Answer 2

Agar Vs Agarose

Answer 3

This Site Might Help You.

RE:
why do we use in electrophoresis agarose instead of agar?

Answer 4

Agarose gel electrophoresis is a method used in molecular biology to separate DNA strands by size, and to estimate the size of the separated strands by comparison to known fragments (DNA ladder). This is achieved by pulling negatively charged DNA molecules through an agarose matrix with an electric field. Shorter molecules move faster than longer ones. the agar is basically a food used to excite cell walls into allowing you to manipulate the dna. for instance when we were in our biology lab. we used the agar to allow us to inject E.coli with Fluorescent genes from a jelly fish. the agar allows us to heat the e.coli then excite the cell wall to allow us to implant the flourescence of the jelly flish. the we cool down the e.coli & let it incubate for a day & then you have glowing e.coli. hope that helps explain it.

Answer 5

If your bands are fuzzy the you may want to run them more slowly, generally that improves the resolution. I have used TAE and TBE buffer (different lab groups do things differently) I didn't notice any difference in the quality of results. The other thing to consider is how thick your gels are, I find if I'm running a small sample on a thick agarose gel the bands tend to become blurred.

Answer 6

the agarose is used as it is cabable of producing pores according to concentration used but the agar wont form the pores as it is only a gelling agent