what is the differende bettween dideoxyribose and deoxyribose
Dideoxyribose is a modified form of the sugar deoxyribose that lacks a hydroxyl group on the 3' carbon atom. Deoxyribose is a five-carbon sugar molecule found in nucleotides that make up DNA. The difference between the two is that deoxyribose has a hydroxyl group on both the 2' and 3' carbon atoms, whereas dideoxyribose lacks the hydroxyl group on the 3' carbon atom. This difference affects the ability of nucleotides containing dideoxyribose to form phosphodiester bonds and therefore, DNA sequencing reactions.
The main difference between dideoxyribose and deoxyribose lies in their chemical structure and their respective roles in DNA sequencing.
1. Deoxyribose: Deoxyribose is a sugar molecule that forms the backbone of DNA. It is a component of deoxyribonucleotides, which are the building blocks of DNA. Deoxyribose contains five carbon atoms and has a hydroxyl (-OH) group attached to each carbon except the 2nd carbon, which lacks the -OH group. The absence of the -OH group at the 2nd carbon makes deoxyribose different from ribose, which is found in RNA.
2. Dideoxyribose: Dideoxyribose is a modified form of deoxyribose. In dideoxyribose, the hydroxyl group at the 3rd carbon is replaced by just a hydrogen atom (-H). This modification inhibits the further elongation of the DNA chain because it lacks the necessary hydroxyl group to form a phosphodiester bond with the next nucleotide's phosphate group. Therefore, dideoxyribose is used in DNA sequencing techniques, specifically the Sanger sequencing method.
In summary, deoxyribose is a regular sugar found in DNA, while dideoxyribose is a modified version that is used in DNA sequencing to halt DNA chain elongation at specific nucleotides.