Topic 6.5 Gas Exchange IB Objective Students will know that the lungs are actively ventilated to ensure that gas exchange can occur passively Distinguish between ventilation, gas exchange and cell respiration Explain the need for a ventilation system I. All Living Things Respire Why living things must respire (breathe): 1. Cellular Respiration ? controlled release of energy in the form of ATP from organic processes in the cell C6H12O6 + O2 ---> 6CO2 + 6H20 + ATP 2. Gas Exchange -- Exchange of gases (Oxygen, Carbon Dioxide) between an organism and it environments 3. Ventilation - process of "changing" or replacing gas (Oxygen, Carbon Dioxide) in a space (ex: lungs) II. Ventilation A. Single celled organisms can easily diffuse gas in and out of a cell