All of the following statements about gel electrophoresis ar

All of the following statements about gel electrophoresis are true EXCEPT:

Agarose separates DNA molecules based solely on charge

Ethidium bromide is used to visualize DNA.

DNA migrates toward the positive electrode because it is negatively charged.

Standards are used to determine the size of DNA molecules.

All of the above are true.

I\'m pretty sure its not the third one

Solution

ANS:

True answers:

A. Agarose separates DNA molecules based solely on charge

Explanation: Nucleic acid molecules present in the DNA is separated by application of electric field and Nucleic acid s moves through a matrix of agarose. DNA is negatively charged due to this DNA moves towards positively charged anode, in this agarose gel mediated as buffer.

B. Ethidium bromide is used to visualize DNA.

Explanation: After completion of electrophoresis, DNA molecules is stained with Ethidium bromide. It

intercalated into DNA, fluoresce under U. V light. Now the DNA may visualized.

C. DNA migrates toward the positive electrode because it is negatively charged.

Explanation: DNA molecule is negatively charged, so it will migrate towards the positively charged anode.

False answer:

D. Standards are used to determine the size of DNA molecules.

Explanation: Some scientists are mainly used DNA standard or DNA standards (nucleic acid standards) in DNA quantification by UV spectrometer.

In this the number before a DNA ladder indicates the size interval of the DNA fragments.

Note: In most cases all of the above given options are true.