Dideoxynucleotides

Definition

Dideoxynucleotides are modified nucleotides that lack a 3' hydroxyl group, preventing DNA strand elongation. They are crucial in DNA sequencing techniques like Sanger sequencing.

5 Must Know Facts For Your Next Test

1. Dideoxynucleotides terminate DNA synthesis because they lack the necessary 3' hydroxyl group.
2. Their incorporation into growing DNA strands is random, creating fragments of varying lengths.
3. They are labeled with fluorescent dyes for detection in automated sequencing methods.
4. Sanger sequencing uses dideoxynucleotides to determine the nucleotide sequence of DNA.
5. Dideoxynucleotides differ from deoxynucleotides by the absence of an additional oxygen atom at the 3' position.

Review Questions

• Why do dideoxynucleotides terminate DNA synthesis?
• How are dideoxynucleotides used in Sanger sequencing?
• What is the key structural difference between dideoxynucleotides and deoxynucleotides?

Related terms

Deoxynucleotide: A nucleotide containing deoxyribose, which forms the building blocks of DNA.

Sanger Sequencing: A method for determining the nucleotide sequence of DNA using chain-terminating dideoxynucleotides.

Fluorescent Dye: A molecule that absorbs light at one wavelength and emits light at a different wavelength, used for labeling molecules in various types of assays including DNA sequencing.