What is the Five-Carbon Sugar Found in DNA?
DNA, or deoxyribonucleic acid, is the molecule that contains the genetic instructions used in the development and function of all living organisms. It is a long, double-stranded helix made up of nucleotides, which are the building blocks of DNA. Each nucleotide is composed of three components: a five-carbon sugar, a phosphate group, and a nitrogenous base.
The Five-Carbon Sugar Found in DNA
The five-carbon sugar found in DNA is deoxyribose. Deoxyribose is a type of sugar that is found in the backbone of DNA, where it is linked to phosphate groups to form a phosphodiester bond. This bond gives DNA its characteristic double-stranded structure.
Properties of Deoxyribose
Deoxyribose is a five-carbon sugar, meaning it has five carbon atoms in its molecular structure. It is a ketose, meaning it has a carbonyl group (-CHO) in its structure. Deoxyribose is also a chiral molecule, meaning it has a non-superimposable mirror image, known as an enantiomer.
Comparison with Other Sugars
Deoxyribose is different from other sugars, such as ribose, which is found in RNA (ribonucleic acid). Ribose is a ribose, meaning it has a hydroxyl group (-OH) at the 2′ position, whereas deoxyribose has a hydrogen atom at the 2′ position.
Role of Deoxyribose in DNA Structure
Deoxyribose plays a crucial role in the structure of DNA. The phosphodiester bond between deoxyribose and phosphate groups forms the backbone of DNA, which provides a rigid framework for the double-stranded helix. The sugar-phosphate backbone is responsible for the double-helical structure of DNA, which is essential for the stability and function of the molecule.
Functions of Deoxyribose
Deoxyribose has several functions in DNA:
- Provides a structural framework: Deoxyribose forms the backbone of DNA, providing a framework for the nitrogenous bases to bind to.
- Helps to maintain the double-helical structure: The phosphodiester bond between deoxyribose and phosphate groups helps to maintain the double-helical structure of DNA.
- Protects the genetic information: Deoxyribose helps to protect the genetic information encoded in DNA by forming a strong bond with the phosphate group.
Conclusion
In conclusion, deoxyribose is the five-carbon sugar found in DNA. It plays a crucial role in the structure and function of DNA, forming the backbone of the molecule and helping to maintain its double-helical structure. Deoxyribose is a unique sugar that is found only in DNA and is essential for the stability and function of the molecule.
Table: Comparison of Deoxyribose and Ribose
| Deoxyribose | Ribose | |
|---|---|---|
| Number of carbon atoms | 5 | 5 |
| Type of sugar | Ketose | Aldose |
| Hydroxyl group at 2′ position | Hydrogen atom | Hydroxyl group (-OH) |
| Found in | DNA | RNA |
References
- Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular Biology of the Cell. 5th edition. New York: Garland Science.
- Lehninger, A. L., Nelson, D. L., & Cox, M. M. (2008). Principles of Biochemistry. 4th edition. New York: W.H. Freeman and Company.
- Watson, J. D., & Crick, F. H. (1953). Molecular Structure of Nucleic Acids; A Structure for Deoxyribose Nucleic Acid. Nature, 171(4356), 737-738.