2
Question
During isolation of genetic material, the chemical used to precipitate out the purified DNA is-
During isolation of genetic material, the chemical used to precipitate out the purified DNA is-
Open in App
Solution
The correct option is B Chilled ethanol
Isolation of genetic material is the process of obtaining genomic DNA or plasmid DNA in the pure form from host cells or bacterial cells respectively.
In order to achieve this, the cells are first subjected to enzymes like lysozyme, cellulase or chitinase to dissolve the cell wall. This releases DNA along with other cellular macromolecules such as RNA, proteins, polysaccharides, and lipids.
The second step is removal of the other macromolecules using appropriate enzymes such as proteases for digesting proteins, ribonucleases for digesting RNA.
The third step is the precipitation of purified DNA from the medium. This is done using chilled ethanol. DNA is a polar molecule due to the negative charges on its phosphate backbone. Thus, it is readily soluble in water. Chilled ethanol has less dielectric constant and allows easy bonding between the negative charges on the phosphate backbone of DNA and any positive ion present in the extraction solution forming stable ionic bonds. Thus, the polarity and solubility of DNA is lost and it readily precipitates.
Loading dye is used for loading DNA samples into agarose gel wells and tracking migration during electrophoresis. Bromophenol blue is often used as a tracking dye during agarose gel electrophoresis.
Ethidium bromide is a fluorescent dye used to stain DNA. It binds to DNA and on exposure to UV radiations, the dye fluoresces and the DNA fragments can be viewed as orange bands.
So, the correct answer is - chilled ethanol.
Isolation of genetic material is the process of obtaining genomic DNA or plasmid DNA in the pure form from host cells or bacterial cells respectively.
In order to achieve this, the cells are first subjected to enzymes like lysozyme, cellulase or chitinase to dissolve the cell wall. This releases DNA along with other cellular macromolecules such as RNA, proteins, polysaccharides, and lipids.
The second step is removal of the other macromolecules using appropriate enzymes such as proteases for digesting proteins, ribonucleases for digesting RNA.
The third step is the precipitation of purified DNA from the medium. This is done using chilled ethanol. DNA is a polar molecule due to the negative charges on its phosphate backbone. Thus, it is readily soluble in water. Chilled ethanol has less dielectric constant and allows easy bonding between the negative charges on the phosphate backbone of DNA and any positive ion present in the extraction solution forming stable ionic bonds. Thus, the polarity and solubility of DNA is lost and it readily precipitates.
Loading dye is used for loading DNA samples into agarose gel wells and tracking migration during electrophoresis. Bromophenol blue is often used as a tracking dye during agarose gel electrophoresis.
Ethidium bromide is a fluorescent dye used to stain DNA. It binds to DNA and on exposure to UV radiations, the dye fluoresces and the DNA fragments can be viewed as orange bands.
So, the correct answer is - chilled ethanol.
Suggest Corrections
0
Similar questions
View More
Join BYJU'S Learning Program
Explore more
Join BYJU'S Learning Program
