Fun for all eukaryotic organisms…. Cell Respiration 1

Cell respiration (C.R.) occurs in the mitochondria. It occurs in ALL eukaryotic cells. The purpose is to use glucose to make 36 ATP molecules. Background 2

C 6 H O 2  6 CO H ATP Hmmmm…does this look familiar? What are the reactants? What are the products? Equation for Cell Respiration 3

Where does it occur? – In the cytoplasm of the cell Does it need oxygen? – No! This part of C.R. is “anaerobic” An- = without -aerobic = oxygen What happens? – Glucose is broken in half to create 2 pyruvic acid molecules. – 4 ATP are produced, but 2 are used in the process of glycolysis, leaving a net gain of 2 ATP. 1. Glycolysis: 4

Where does it occur? – In the mitochondria Does it require oxygen? – YES!!! (It is an aerobic process) What happens? – The pyruvic acids (produced in glycolysis) are broken down and CO2 is released was waste – Result: 2 ATP are produced. 2. Krebs Cycle 5

– Where does it occur? In the mitochondria – Does it need oxygen? YES!!! (It is an aerobic process) – What happens? In glycolysis and the Krebs cycle, high energy electrons were produced. These electrons are used to make 32 ATP molecules. 3. Electron Transport Chain 6

Glycolysis: 2 ATP molecules Krebs Cycle: 2 ATP molecules Electron Transport Chain: 32 ATP molecules 7 So, where do the 36 ATP molecules come from??

Then “Lactic Acid Fermentation” occurs. – After glycolysis, if there is a lack of O2 (perhaps due to increased exercise), the pyruvic acid cannot enter the Krebs Cycle. – Instead, the pyruvic acids are changed into lactic acid, which when used by your cells gives 2 ATP. – Problem: lactic acid is poison for the cells, which you feel as “burning” when you exercise. – You cannot continue for long with this burning, so typically, you slow down and breathe more to get oxygen. What happens if there is a lack of oxygen? 8

Alcohol Fermentation: – Occurs in yeast when making bread and beer. – Yeast produces alcohol as a waste product when there is low oxygen levels. Yes, THAT kind of alcohol. – THIS DOES NOT HAPPEN IN YOUR CELLS! If it did, people would exercise to get drunk. – All of our students who skip class would be at the track running laps! Another fermentation…not in your cells. 9

Lets review: ComparisonPhotosynthesisCell Respiration Function: Location: Equation: 6 CO2 + 6 H20 + light  C6H12O6 + 6 O2 C 6 H O 2  6 CO H ATP Reactants: Products: Glucose production Energy (ATP) Production ChloroplastsMitochondria CO 2 ; H 2 0; lightGlucose & O 2 CO 2 ; H 2 0; 36 ATP 10