This document summarizes Chapter 4 of a biology textbook, which covers the expression of biological information over 6 hours. It discusses DNA and genetic information, DNA replication, protein synthesis, and the lactose operon. The first section covers DNA structure, including the Watson and Crick model showing DNA as a double helix composed of nucleotides with phosphate, sugar, and nitrogenous base components. DNA acts as the carrier of genetic information by encoding protein sequences and allowing heredity and adaptation through replication and mutation.

1. CHAPTER 4: Expression Of Biological Information (6 Hours)

9. DNA DNA molecule structure 5` phosphodiester linkage Hydrogen bond o P o P o P o P P o P o P o P o C T G A A T G C 5` 3` 3` Hydrogen bond

10. BASIC STRUCTURE OF DNA

11. BASIC STRUCTURE OF DNA

12. IF……. So…

16. Wild type S mooth, virulent ( IIIS ) Mutant type R ough, non-virulent ( IIR ) Symbol of bacteria

20. Experiments carried out by Avery et. al.