Major event in the biological revolution was the human genome project: mapped the entire structure of human genetic material. Within nearly every cell, there is a genome: genome provides instructions for everything, from how to grow a nose to where to place it on the body. what part of the body the cell becomes is determined by which genes are turned on and off within the cell and this is determined from the cues from outside the cell. genome option, environment determines which option is taken. turning on and off of genes provides insight how physical bodies develop and how the brain works. genetics typically used to describe how characteristics are passed down by inheritance, but also refers to the process of turning on and off of genes. Within each cell there are chromosomes, which are structured made up of genes: typical human: 23 pairs, half of each from different parent.