This lab investigates the effects of Sucrose concentration on cell respiration in yeast. Yeast produces ethyl alcohol and CO2 as a byproduct of anaerobic cellular respiration, so we measured the rate of cellular respiration by the amount of CO2 produced per minute. The results show a trend wherein increased concentrations of sucrose increase the rate of cellular respiration.
All living cells require energy in order to proceed with cellular processes such as active transportation, and the synthesis of molecules. ATP (Adenine Tri-Phosphate) is a molecule, which provides energy in a form that cells can use for such cellular processes. Cellular respiration is the process in which cells produce this energy to survive. It occurs in the mitochondria of the cell and is is vital for the survival of most organisms because cells cannot use the energy in glucose until it is stored in ATP. In the presence of oxygen, organisms can respire aerobically. The balanced chemical equation for aerobic respiration is: C6H12O6 + 6O2 -> 6 CO2 + 6 H2O + ~ 36-38 ATP
In the process of aerobic respiration, C6H12O6 is first broken down into 2 3-Carbon molecules called pyruvate or pyruvic acid through the process of Glycolysis, which literally means, “Sugar decomposition.” A net of 2 ATP is produced during Glycolysis. When oxygen is available, these 2 pyruvates move on to the Krebs cycle and electron transport chain to produce the remaining 34-36 ATP. Fig 1.1: An overview of Aerobic Cell Respiration (http://www.phschool.com/science/biology_place/biocoach/images/cellresp/glucover.gif)
In the process of anaerobic respiration, C6H12O6 is also broken down into 2 pyruvates through the process of Glycolysis. However because oxygen is unavailable, instead of the Krebs cycle and the electron transport system occurring, fermentation occurs