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CELL RESPIRATION. Chapter 9 Pages 221-225. I. Chemical Energy & Food A. Energy cannot be created or destroyed. Our body converts the stored energy in glucose to usable energy called ATP II. Overview of Cell Respiration A. Definition:
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CELL RESPIRATION Chapter 9Pages 221-225
I. Chemical Energy & Food A. Energy cannot be created or destroyed. • Our body converts the stored energy in glucose to usable energy called ATP II. Overview of Cell Respiration A. Definition: - Process that releases energy by breaking down glucose, or other organic molecules, in the presence of oxygen.
Example: There is too much energy stored in glucose, so its broken down slowly in order not to lose any energy. This energy is stored in ATP. B. What is Energy? - The ability to do work. C. ATP is a nucleotide. 1. Consists of 3 phosphate groups, the sugar ribose, and the nitrogen base adenine.
2. The energy in ATP is stored between the bonds of its phosphate groups. 3. When a -P group is added to another molecule, it will have enough energy to react with other molecules.
Calories • One gram of glucose releases 3811 calories of heat when burned. • What is a calorie? • The amount of energy needed to raise 1 gram of H2O 1°C. • The Calorie that is used on food labels is 1 kilocalorie or 1000 calories
B. Overall Equation 6O2 + C6H12O6 6CO2 + 6H2O + “Energy(ATP)” III. Stages of Cellular Respiration A. Glycolysis 1. Process where one molecule of glucose is broken in half, making two molecules of Pyruvate (3-Carbon Molecule). 2. Takes place in the cytoplasm. 3. 2 ATPs needed to start reaction. (Activation Energy)
4. 4 ATPs and 2 NADH are produced. - These two molecules will drive further reactions. 5. Oxygen is NOT NEEDED for this step.
Glycolysis review activity • Draw a flow chart of the process of glycolysis. Include the following words in the flowchart: • Glucose • Pyruvate • NAD+ • NADH • ATP • ADP
What about when oxygen is NOT present? B. Alcoholic Fermentation Pyruvic Acid + NADH Alcohol + CO2 + NAD+ - Used by yeast and other microorganisms. - This process causes bread dough to rise. Do you know why????
C. Lactic Acid Fermentation Pyruvic Acid + NADH Lactic Acid + NAD+ -The production of Lactic acid produces a painful,burning sensation in muscles. When do you think this happens? - Prokaryotes that undergo Lactic Acid Fermentation are used to produce some beverages, cheese, yogurt, buttermilk and sour cream.
What about if oxygen “IS” present? D. Krebs Cycle (Citric Acid Cycle) - An aerobic reaction (Oxygen is needed). - Takes place within the mitochondria. - The Mitochondria has two parts: 1. Cristae (Inner Membrane) 2. Matrix (Liquid portion inside inner membrane)
- Named after Hans Krebs (British Biochemist) - Occurs within the MATRIX. What Happens Here? - Pyruvic acid is first converted into Acetyl CoA. - Acetyl CoA then enters the Krebs Cycle and is broken down over the course of several reactions. - As Acetyl CoA is broken down, CO2 is released as a byproduct. * This is what we exhale!
- In this cycle, two electron carriers are used: 1. NAD+ NADH 2. FAD FADH2 - These two electrons carriers will be used to make ATP in the last step of aerobic respiration.
Sum of the Krebs Cycle: 1 Molecule of Glucose Produces = 8 NADH 2 FADH2 2 ATP * NADH and FADH2 will be used to create ATP during the Electron Transport Chain (ETC).
Electron Transport Chain (ETC) - Uses high-energy electrons from the Krebs cycle to convert ADP into ATP. - Occurs along the inner membrane of the mitochondria. - The electrons from NADH & FADH2 are passed along a series of proteins. - This movement of electrons pumps H+ ions into the intermembrane space.
- The H+ ions will move from high to low concentration through the enzyme ATP Synthase. - This movement causes the enzyme to move like a turbine and bind ADP to P forming ATP. Click for animation!
Totals of Aerobic Respiration * Remember that anaerobic respiration only produces 2 ATPs per glucose. - With aerobic respiration, a total of 36 ATPs are produced per glucose.