110 likes | 338 Views
Fermentation. Michael Slemp. Review of Cellular Respiration. Where does glycolysis happen? Is it aerobic or anaerobic process?. Cytoplasm, anaerobic process. 2. What is the final product of glycolysis?. Two 3-carbon molecules (pyruvate), 2 ATP.
E N D
Fermentation Michael Slemp
Review of Cellular Respiration Where does glycolysis happen? Is it aerobic or anaerobic process? Cytoplasm, anaerobic process 2. What is the final product of glycolysis? Two 3-carbon molecules (pyruvate), 2 ATP 3. Where does cellular respiration happens? Is it aerobic or anaerobic process? Mitochondria, aerobic process 4. Name the 2 steps of cellular respiration? Where does each step happen? 1. Krebs cycle – matrix of mitochondria. 2- electron transport – inner membrane of mitochondria 5. What are the final products of each step? 1- small amounts of ATP, other energy-carrying molecules, co2 2-large number of ATP, water, heat
Oxygen present Cellular Respiration Large amount of ATP produced. Glycolysis aerobic glucose Oxygen NOT present anaerobic 2 ATP molecules Fermentation Two 3-carbon molecules
In order to understand fermentation we need to look at glycolysis a little bit closer We said that the final product of glycolysis are two 3-carbon molecules and 2 molecules of ATP Remember ? ATP = $1.00 bill During the splitting of glucose more energy is released that 2 molecules of ATP can capture This extra energy is captured into other energy-carrying molecule (NAD+) Remember ? During Krebs cycle, energy-carrying molecules were also formed. These were our $20.00 bills which entered electron transport for creation of ATP?
Glycolysis + 2 ATP + extra energy glucose Two 3-carbon molecules (2 pyruvates) Packed into NAD+ molecule NAD+ + extra energy = NADH Energy-poor molecule (pennies) Energy-rich molecule ($20.00), too large for cell use
Cellular respiration only happens during the presence of oxygen. So what would happen in anaerobic conditions, when products of glycolysis cannot enter process of cellular respiration? Finally, all NAD+ would be used up, cell could not produce no more ATP inglycolysisand would die. That is why, in anaerobic conditions, cell enters process of fermentation!
FERMENTATION • Anaerobic process • Does not produce more ATP • Recycles NAD+ (which makes possible for glycolysis to continue) • Without fermentation, glycolysis would stop Different cells (like yeast, plants) use different type s of fermentations. Why is this important? Think of cheese, bread, yogurt, wine, alcohol… The taste and texture of fermented food is based on the final product of fermentation. E.g. alcohol fermentation = alcohol
For example: Lactic acid fermentation Two 3-carbon molecules (pyruvates) Glucose energy 2 lactic acid molecules NADH = energy + NAD+ Glycolysis 2 ATP Fermentation This process is used by our muscle cell during strenuous exercise (when not enough O2). Lactic acid causes muscle burning. NAD+ + energy = NADH Waste product = lactic acid (sour taste in milk and yogurt)
Another example: Alcoholic fermentation 2 alcohol molecules + 2 CO2 (carbon dioxide) Pyruvate Glycolysis Fermentation Yeast use alcoholic fermentation during the production of bread. CO2 causes the dough to puff up and rise. During baking, CO2 evaporates into air and yeast is killed by heat of baking. Waste product: alcohol and carbon dioxide