Dna

• Each nucleotide has three components: a sugar (deoxyribose), a phosphate group, and a nitrogenous base.
• The two strands of DNA run antiparallel to each other, meaning they have opposite orientations.
• In DNA, A always pairs with T through hydrogen bonds between their complementary structures.
• Bases are attached to the deoxyribose sugars on one side and the phosphates on the other.
• Cytosine is the only pyrimidine that can form three hydrogen bonds when paired with guanine.
• DNA is double-stranded and contains four different bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
• DNA replication occurs semiconservatively, where one new strand contains all new nucleotides while the other contains some old and some new nucleotides.
• Hydrogen bonding occurs between the bases on the inside of the helix, forming a major groove and minor groove.
• DNA replication occurs by semiconservative replication, where each new double helix contains one old strand and one newly synthesized strand.
• The structure of DNA was determined by James Watson and Francis Crick using X-ray crystallography data from Rosalind Franklin.
• Replication begins at specific sites called origins of replication.
• Helicase unwinds the parental DNA molecule into single strands.
• Each chain runs in opposite directions and forms a right-handed double helix.
• Each new strand has a free end called an Okazaki fragment.
• Nucleic acids consist of monomers called nucleotides, which contain a pentose sugar, a phosphate group, and a nitrogenous base.
• Nucleic acids consist of monomers called nucleotides, which contain a pentose sugar, a phosphate group, and a nitrogenous base.
• DNA has two antiparallel polynucleotide chains held together by hydrogen bonds between complementary base pairs.