Structure of nucleic acids and replication of DNA

Need to know

What you need to know

• Nucleotides are linked by phosphodiester bonds to form polynucleotide chains.
• The formation of these chains occurs in the nucleus during the interphase of the cell cycle.
• In the double helix, a purine base (A or G) always pairs with a pyrimidine base (T or C).
• The sides of the DNA 'ladder' consist of an alternating sugar-phosphate backbone.
• The 'rungs' of the ladder are made of paired nitrogenous bases.
• Hydrogen bonds form between the complementary base pairs, holding the two DNA strands together.

Explanation

Structure of nucleic acids and replication of DNA

1. Nucleotides are linked by phosphodiester bonds to form polynucleotide chains.
2. The formation of these chains occurs in the nucleus during the interphase of the cell cycle.
3. In the double helix, a purine base (A or G) always pairs with a pyrimidine base (T or C).
4. The sides of the DNA 'ladder' consist of an alternating sugar-phosphate backbone.