In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel


Here, we will talk about the biology question – In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel. You can find the answer and explanations below.

We collected as a question of the MCAT practice test.

In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel.

  • Below are the answer and explanations.

Gel electrophoresis

Agarose gel electrophoresis is a commonly used method for the separation and identification of DNA and RNA. This electrophoresis method uses agar gel as support to separate the mixture by using the charge effect and molecular sieve effect of DNA molecules during the swimming motion.

DNA molecules are negatively charged in a solution above their isoelectric point and move toward the anode in an electric field. At a certain electric field strength, the migration rate of DNA molecules depends on the molecular sieve effect, i.e., the size and configuration of the molecule itself are the main influencing factors.

The migration speed of DNA molecules is inversely proportional to their relative molecular weight.

Different conformations of DNA molecules have different migration velocities. For example, a sample of circular DNA molecules. There are three conformations of these molecules: covalently closed-loop superhelical molecules (cccDNA), open-loop molecules (ocDNA), and linear DNA molecules (IDNA).

The order of migration velocity of these three different conformations of molecules when electrophoresis is performed is:cccDNA > IDNA > ocDNA

Why can the gel electrophoresis technique separate DNA?

DNA molecules have a charge effect and a molecular sieve effect when swimming in an agarose gel. DNA molecules are negatively charged in a pH solution above the isoelectric point and move toward the positive pole in an electric field.

Due to the repetitive nature of the sugar-phosphate backbone in structure, double-stranded DNA of the same size has almost equal net charge. And different sizes of DNA has a different net charge, the same electric field conditions in the same force is not the same.

In addition, DNA molecules in the gel will also be affected by the resistance, resistance has the size and structure of DNA to determine. The size is the number of deoxyribonucleotides or molecular weight size. The general structure of molecular weight DNA under the same environment migration speed relationship is as follows: ring > double-stranded > ring open loop.

Correct Answer

Here is the correct answer to In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel.

  • negative … positive

So, In gel electrophoresis DNA molecules migrate from negative to positive ends of the gel.

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