BIOLOGY 1A03 Lecture 1: THEME 1, Module 2

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Kim Dej

Document Summary

Recognize the evolution of organelles through endosymbiosis. Describe the important roles played by chloroplasts and mitochondria. Explain why carbohydrates are the primary source of energy in our bodies. Life and photosynthesis began ~4 billion years ago. Life on earth was almost exclusively unicellular for most of earth"s history and oxygen was virtually absent from the oceans and atmosphere: this was a very harsh and inhospitable environment. As we will learn, it is likely that many unicellular organisms began interacting with one another and the interactions that allowed these organisms to deal with harsh environments were selected for, and eventually these organisms became co-dependent. The evolution of these relationships can be observed when we compare prokaryotic and eukaryotic organisms. Eukaryotic and prokaryotic cells have structural components that are similar and others that differ: both have an external membrane that separates the inside of the cell from the outside.