* Phosphodiester bonds: These are covalent bonds that link the sugar-phosphate backbone of the DNA strand. They connect the 3' carbon of one sugar molecule to the 5' carbon of the next sugar molecule.
* Hydrogen bonds: These are weaker bonds that hold the two strands of DNA together, forming the double helix structure. They occur between the nitrogenous bases of the two strands (A with T, and C with G).
So, while there are two different types of bonds, the answer to your question depends on how you're looking at it.
* Within a single DNA strand: There are phosphodiester bonds holding the nucleotides together.
* Between the two strands of DNA: There are hydrogen bonds holding the two strands together.
Let me know if you'd like more detail on either of these types of bonds!
