Which of the following are DNA chain-terminator molecules and were used in the original biochemical approach to DNA sequencing devised by Frederick Sanger in the 1970s?
A) 2'-Deoxyribonucleotides
B) 3'-Deoxyribonucleotides
C) 2', 3'-Dideoxyribonucleotides
D) 2'-Deoxyuridine and 2'-deoxyadenosine
E) Uridine and adenosine

Question

Quizplus · Accepted Answer

2', 3'-dideoxyribonucleotides lack the 3' hydroxyl group necessary for the formation of a phosphodiester bond with the next incoming nucleotide, thus acting as chain terminators during DNA synthesis. This property was utilized in Sanger sequencing, where DNA polymerase was used to synthesize complementary strands of DNA in the presence of four different dideoxyribonucleotides, each labeled with a different fluorochrome. The resulting fragments of varying lengths were separated by gel electrophoresis, and the base sequence was read off from the fluorescence pattern.

Which of the Following Are DNA Chain-Terminator Molecules and Were