1. Base Pairing:
* Adenine (A) always pairs with Thymine (T) via two hydrogen bonds.
* Guanine (G) always pairs with Cytosine (C) via three hydrogen bonds.
This specific pairing is called complementary base pairing and is essential for the stability and function of DNA.
2. Phosphodiester Bonds:
* Each base is attached to a sugar molecule (deoxyribose) to form a nucleoside.
* The nucleoside is then attached to a phosphate group, forming a nucleotide.
* Nucleotide monomers are linked together by phosphodiester bonds between the phosphate group of one nucleotide and the sugar molecule of the next. This creates a sugar-phosphate backbone, which forms the structural framework of the DNA molecule.
3. Double Helix:
* The two complementary strands of DNA wind around each other to form a double helix.
* The base pairs are stacked inside the helix, with the sugar-phosphate backbones forming the outside of the helix.
In summary:
* Base pairing: Adenine pairs with Thymine, and Guanine pairs with Cytosine.
* Phosphodiester bonds: Link nucleotides together in each strand.
* Double helix: The two strands are held together by base pairing and twist around each other.
This intricate structure ensures that DNA can be replicated accurately and that the genetic information it carries can be passed from one generation to the next.
