This module examines the way in which genetic information, encoded by the DNA of the cell, is replicated and passed on to each new generation of cells and whole individuals. The ways in which genes affect the characteristics of a cell or organism are explored at the molecular level. The fundamentals of these processes are very similar in all organisms but the unique features of eukaryotes and prokaryotes are highlighted. We will also examine the consequences of mutation and look at some examples of diseases and conditions caused by defective genes and alterations in chromosome number or structure.