* Nucleotides: These are the building blocks of DNA. Each nucleotide consists of three parts:
* A sugar molecule: Deoxyribose
* A phosphate group: This is the acidic part of the nucleotide.
* A nitrogenous base: There are four different bases:
* Adenine (A)
* Thymine (T)
* Guanine (G)
* Cytosine (C)
* Hydrogen bonds: These bonds hold the two strands of the DNA double helix together. Adenine always pairs with thymine (A-T) and guanine always pairs with cytosine (G-C). These pairings are based on the size and shape of the bases, which allows for stable hydrogen bonds to form.
Structure of the Double Helix:
* Two strands: The DNA double helix is made of two strands of nucleotides running in opposite directions (antiparallel).
* Sugar-phosphate backbone: The phosphate groups and sugar molecules of each nucleotide form the backbone of each strand.
* Bases on the inside: The nitrogenous bases are positioned on the inside of the helix, facing each other and paired according to the A-T and G-C rule.
* Twisted ladder: The two strands twist around each other, forming a double helix that resembles a twisted ladder.
The specific sequence of bases along the DNA molecule is what determines the genetic information that is stored in the DNA.
