9700 · 6.1
Structure of nucleic acids and replication of DNA
Welcome to Topic 6.1, where we unlock the secrets of **nucleic acids** – the molecules that carry genetic information in all living organisms. We'll dive deep into the intricate structure of **DNA** (deoxyribonucleic acid) and **RNA** (ribonucleic acid), and then explore the remarkable process of **DNA replication**, ensuring that genetic information is faithfully passed from one generation of cells to the next. Get ready to understand the very blueprint of life! Key points align with **A-Level Notes** 9700 Biology chapter **6** (topic **6.1**). Notes and diagrams from **A-Level Notes** chapter **6**, topic **6.1** (2 pages).
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
- 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.