At which carbon of a pentose sugar does phosphate bind?

Phosphate groups bind to the 5' carbon of a pentose sugar in nucleic acids such as DNA and RNA. This is because the 5' carbon is where the phosphate group is attached, forming a crucial part of the backbone structure of nucleic acids. The attachment at the 5' position is essential for creating the phosphodiester bonds that link nucleotides together in a chain, allowing the formation of the elongated structure of nucleic acids.

The 5' carbon is also significant in molecular biology since it defines the directionality of the DNA or RNA strand, which is important for processes such as transcription and replication. Additionally, the 3' carbon can also have an important role, as it forms the other end of a nucleotide with a hydroxyl group (–OH), but it is specifically the 5' carbon that is involved in the binding of the phosphate group. Understanding this aspect of nucleic acid structure is fundamental for comprehending genetic functions and mechanisms.