The Sugar-Phosphate Backbone Is The Structural Framework
- This backbone is created when individual nucleotides are joined in a chain by covalent bonds.
- It provides the structural framework of nucleic acids while allowing the sequence of nitrogenous bases to encode genetic information.
Formation of the Sugar-Phosphate Backbone
- To form a nucleotide chain, individual nucleotides are joined by covalent bonds in a specific configuration:
- Nucleotides are joined by covalent bonds called phosphodiester bonds, which form between the phosphate group of one nucleotide and the 3' hydroxyl group on the pentose sugar of the next nucleotide.
- This linkage creates a sugar-phosphate backbone with a directional 5' to 3' orientation.
- The phosphodiester bond consists of two ester bonds: one between the phosphate and the 5' carbon of its own sugar, and another between the phosphate and the 3' carbon of the adjacent sugar.
- The nitrogenous bases project outward from the backbone and are not involved in forming the chain.
Definition
Phosphodiester bond
A phosphodiester bond is a covalent bond formed between nucleotides in a nucleic acid chain via condensation.
Phosphodiester bonds are highly stable, ensuring the sugar-phosphate backbone can withstand normal cellular conditions without breaking.
Directionality of the Sugar-Phosphate Backbone
- The sugar-phosphate backbone has a specific directionality, vital for the function of DNA and RNA.
