Question

The fragment sizes that you determined from your gel may not be exactly correct (i.e. they may not be the same as the ideal results). Which of the following three could cause this. a. It is a buffer b. It is a nucleotide c. It is a mutagen d. It chelates divalent cations e. It is an enzyme f. It covalently binds to DNA g. It fluoresces at 590 nm h. It is a polymerase i. It is an intercalating dye

Answer 1

There are various factors that contribute to the abnormal behavior of DNA fragments in the gel. Few of these factors are listed below

It is a buffer: Electric field, pH, and salt concentration are the crucial factors that influence the mobility of DNA in the gel.pH, and salt concentration affects the net charge of the nucleic acid. Hence, these two factors may influence the mobility of the fragment significantly.

It chelates divalent cations: Divalent cations affect the overall charge of the DNA molecule as well as ionic strength of the buffer, hence can affect the mobility of DNA on the gel.

It is an intercalating dye. Intercalating dye such as ethidium bromide intercalates into the DNA strand which results in an altered conformation of the DNA and hence contributes to abnormal mobility of the gel.