Cellular Respiration, Slides of Biology

Download Cellular Respiration and more Slides Biology in PDF only on Docsity! Cellular Respiration The Flow of Energy in Ecosystems Organisms must take in energy from outside sources. Energy is incorporated into organic molecules such as glucose in the process of photosynthesis. Glucose is then broken down in cellular respiration. The energy is stored in ATP. What is Cellular Respiration? * The process in which organisms take molecules broken down from food and release the chemical energy stored in the chemical bonds of those molecules. * It’s important to remember that food is not the direct source of energy. * The energy that is released from chemical bonds during cellular respiration is stored in molecules of ATP. What types of organisms undergo cellular respiration? ¢ While only autotrophs undergo photosynthesis both Heterotrophs AND Autotrophs-——— 5 Undergo cellular respiration. What types of molecules are broken down? * Any food (organic) molecule, or nutrient, including carbohydrates, fats/lipids, and proteins can be processed and broken down as a source of energy to produce ATP. @ a A is oxidized, B is reduced, losing electrons gaining electrons é o a B Oxidized @ @™ Reduced compound A compound B Biochemical Pathway * Cellular Respiration is a biochemical pathway just like photosynthesis in which each step (chemical reaction) of the process is dependent on the products of the previous step. * The cellular respiration equation represents many steps that have taken place. Where does cellular respiration occur? * Cellular respiration takes place in the mitochondria of the eukaryotic cell. * Recall that the mitochondria is considered to be the “powerhouse” of the cell because it produces the majority of a cell’s ATP. Label the Parts of the Mitochondria Mitochondria Inner Structure +» Many similarities exist tiner between the chloroplast ‘Membrane and the mitochondria « Mitochondria has a Matrix Figure 4 Mitochondria Inner Structure double membrane * Mitochondria have their own DNA and only come from preexisting mitochondria. «Mitochondria have a smooth outer membrane «Mitochondria have a folded inner-membrane called the cristae. A folded inner membrane allows more surface area for chemical reactions to occur. «Mitochondria have a center called the matrix. Cellular Respiration in Detail Glucose For the sake of simplicity (as it is in photosynthesis), glucose is used as the example for cellular respiration. Remember that many different types of organic molecules are broken down through cellular respiration. Cellular Respiration Cellular respiration breaks down into these major steps. Glycolysis (anaerobic) Krebs Cycle (aerobic) Electron Transport Chain (aerobic) Energy Carriers Found in Cellular Respiration * ATP * NADH (similar to NADPH in photosynthesis) or Niacin * FADH, — Flavin Adenine Dinucleotide or Riboflavin Glycolysis Pre-Krebs Cycle (Acetyl- CoA) ¢ Before pyruvic acid enters the Krebs Cycle, it combines with an enzyme called Coenzyme A (CoA). * This reaction produces a molecule of Acetyl CoA. « Acetyl CoA is a molecule produced by almost all nutrients (carb., protein, lipids) before entering the Krebs cycle. Pathway to the Krebs Cycle (citric acid cycle) Glycolysis Pyruvic Acid | Acetyl CoA | Krebs Cycle Krebs Cycle (Citric Acid Cycle) + Named after Hans Krebs who won the Nobel Prize for the pathway he discovered in cellular respiration. Krebs Cycle * Cyclical series of oxidation reactions that give off CO, and produce one ATP per cycle * Requires Oxygen (Aerobic) * Turns twice per glucose molecule (produces 1 ATP per turn). + Produces two ATP * Takes place in matrix of mitochondria Krebs Cycle * Acetyl CoA (formed from Pyruvic Acid) combines with a four-carbon molecule to make a molecule of citric acid. * Citric acid is broken down in several steps providing the energy to make NADH, FADH, , ATP. Krebs Cycle (Citric Acid Cycle) 3 Pyruvic acid aot econ <-> [HAD] Acetyl-CoA $ CoA OAR Citric acid GO) apt apt — } apt Krebs Cycle Reactant Summary Pyruvic Acid ADP NAD+ FAD+ Krebs Cycle Product Summary 2 ATP ———Usable energy NADH ~——Goes to ETC FADH, Goes to ETC CO, —Byproduct The Electron Transport Chain The ETC is a series of proteins located in the mitochondrial membrane. It uses high energy electrons from the NADH and FADH, provided by the Krebs Cycle to move H+(protons) across the concentration gradient. These protons pass back down the concentration gradient through ATP synthase to form ATP. Very much like the ETC in the light reactions of photosynthesis. Fermentation * Breathing provides enough oxygen for your body to carry out normal activities. « When you are conducting a high level of activity, breathing doesn’t supply enough air for your cell’s activities. * If oxygen is not present, the products of glycolysis (pyruvic acid and NADH) will enter an alternative process called fermentation. ¢ Fermentation provides enough ATP and recycles NADH into NAD+ so that glycolysis may continue until more oxygen becomes available. Where does fermentation occur? * Cytosol of the cell Two Types of Fermentation * Lactic Acid ¢ Alcoholic Lactic Acid Fermentation * Occurs in muscle cells in the body. * Lactic acid is a waste product of fermentation that will build up and cause your muscles to “burn” during hard exercise. Lactic Acid Fermentation * Lactic acid fermentation a also occurs in some NACterla anda MOGs. Waste products of the fermentation process give cheese different flavors. Yogurt is another product of lactic acid fermentation. Alcoholic Fermentation Alcoholic fermentation is a process used by many yeasts and plants. Also uses the products of glycolysis (NADH and pyruvic acid) to provide enough NAD+ and ATP for glycolysis to continue. Alcoholic Fermentation Alcoholic fermentation is used to make bread or dough rise and is also used for beer and wine. Fermentation