Gel electrophoresis separates DNA molecules on the basis of size. Which of the following DNA molecules would move the slowest? (ebook Module 12.13) A. pBR322 (4.39 kb) B. lambda phage (49 kb) C. F plasmid (100 kb) D. pUC18 (2.69 kb)

Option C

Explanation:

DNA fragments have negative charge and they move towards the positively charged electrode in gel electrophoresis.

There is no difference in the charge carried by the DNA fragments as they all have the equal amount of charge on them.

The difference in speed of large and small molecules of DNA is due to their sizes.

Large DNA molecules do not pass easily through the pores of the gel while the smaller molecules do not face any such hindrance and are easily passed through the gel. Therefore small DNA molecules move faster.

F plasmid has the largest size and hence it will move slowly.

Option C is correct