Question 1

Which one of the following will travel fastest through the gel if the amount of DNA present is same in all?

Accepted Answer

Supercoiled DNA moves fastest through a gel during electrophoresis because its compact structure allows it to navigate the matrix more efficiently than other forms. Circular and nicked DNA are larger and less compact, making them move slower through the gel.

Question 2

How is the size of molecules under analysis measured?

Accepted Answer

The size of molecules under analysis, especially in techniques like gel electrophoresis, is often determined by running a standard molecule (known as a molecular weight marker or ladder) whose size is known in parallel with the sample. This allows for the comparison of the migration distances of the sample molecules to the known sizes of the marker molecules, thereby estimating the sizes of the molecules under analysis.

Question 3

Gel matrices are generally of two types Agarose and Polyacrylamide. Which of the statements is correct with respect to agarose gels.

Accepted Answer

A

Question 4

Polyacrylamide gels are the other types of gels which are commonly used. Which of the following statement is not correct with respect to these types of gels?

Accepted Answer

Polyacrylamide gels are typically cast in vertical assemblies, not horizontal and flat trays, which is more characteristic of agarose gel electrophoresis.

Question 5

If the amount of agarose added is more, the molecular under analysis should have the following characteristic………………..

Accepted Answer

Agarose gel concentration inversely affects the pore size of the gel; a higher concentration of agarose forms a gel with smaller pores. Small-sized molecules require a gel with smaller pores for effective separation, hence more agarose is needed for analyzing smaller molecules.

Question 6

In the case of electrophoresis of single stranded DNA or RNA, which type of gels are used?

Accepted Answer

Denaturing gels are used for the electrophoresis of single-stranded DNA or RNA to prevent secondary structures from forming, ensuring that the molecules are separated based on size rather than shape.

Question 7

The technique used to located specific genes in chromosomes is ……………..

Accepted Answer

In situ hybridization is the technique used to locate specific genes on chromosomes by using a labeled complementary DNA, RNA or modified nucleic acids strand (probe) to localize a specific DNA or RNA sequence in a portion or section of tissue (in situ), or, if the tissue is small enough, in the entire tissue (whole mount in situ hybridization), making it possible to see the cellular distribution of genetic material.

Question 8

The separation of charged molecules under the influence of electric current is called……….

Accepted Answer

Electrophoresis is the technique used for the separation of charged molecules, such as DNA, RNA, or proteins, under the influence of an electric current.

Question 9

If further electrophoresis is used for recovery of DNA from gels, the method is termed as ____________

Accepted Answer

Electro-elution is the method used for the recovery of DNA from gels after electrophoresis, where the DNA is eluted out of the gel matrix using an electric field.

Question 10

The greatest separation is obtained in which portion of the gel?

Accepted Answer

The greatest separation is obtained in the lower portion where the anode is because the negatively charged molecules migrate towards the anode and get separated according to their size and charge.

Quiz 5: Gel Electrophoresis Techniques and Applications