PLSC184 respiration

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Information about PLSC184 respiration

Published on February 7, 2008

Author: Dante


PLANT SCIENCE 184:  PLANT SCIENCE 184 Cellular Respiration: Harvesting Chemical Energy Slide2:  Bacteria are used to produce yogurt, sour cream, pepperoni, and cheese Both carbon monoxide and cyanide kill by disrupting cellular respiration Slide3:  All the energy in all the food you eat can be traced back to sunlight If you exercise too hard, your muscles shut down from a lack of oxygen BIOLOGY AND SOCIETY: FEELING THE “BURN”:  When you exercise BIOLOGY AND SOCIETY: FEELING THE “BURN” Muscles need energy in order to perform work Your cells use oxygen to release energy from the sugar glucose Slide5:  Aerobic metabolism When enough oxygen reaches cells to support energy needs Anaerobic metabolism When the demand for oxygen outstrips the body’s ability to deliver it Slide6:  Anaerobic metabolism Without enough oxygen, muscle cells break down glucose to produce lactic acid Lactic acid is associated with the “burn” associated with heavy exercise If too much lactic acid builds up, your muscles give out Slide7:  Physical conditioning allows your body to adapt to increased activity The body can increase its ability to deliver oxygen to muscles Long-distance runners wait until the final sprint to exceed their aerobic capacity Figure 6.1 ENERGY FLOW AND CHEMICAL CYCLING IN THE BIOSPHERE:  ENERGY FLOW AND CHEMICAL CYCLING IN THE BIOSPHERE Fuel molecules in food represent solar energy Energy stored in food can be traced back to the sun Animals depend on plants to convert solar energy to chemical energy This chemical energy is in the form of sugars and other organic molecules Producers and Consumers:  Photosynthesis Producers and Consumers Light energy from the sun powers a chemical process that makes organic molecules This process occurs in the leaves of terrestrial plants Slide10:  Autotrophs “Self-feeders” Plants and other organisms that make all their own organic matter from inorganic nutrients Heterotrophs “Other-feeders” Humans and other animals that cannot make organic molecules from inorganic ones Slide11:  Producers Biologists refer to plants and other autotrophs as the producers in an ecosystem Consumers Heterotrophs are consumers, because they eat plants or other animals Figure 6.2 Chemical Cycling Between Photosynthesis and Cellular Respiration:  The ingredients for photosynthesis are carbon dioxide and water CO2 is obtained from the air by a plant’s leaves H2O is obtained from the damp soil by a plant’s roots Chloroplasts rearrange the atoms of these ingredients to produce sugars (glucose) and other organic molecules Oxygen gas is a by-product of photosynthesis Chemical Cycling Between Photosynthesis and Cellular Respiration Slide13:  Both plants and animals perform cellular respiration Cellular respiration is a chemical process that harvests energy from organic molecules Cellular respiration occurs in mitochondria The waste products of cellular respiration, CO2 and H2O, are used in photosynthesis Slide14:  Figure 6.3 Sunlight energy Ecosystem Photosynthesis (in chloroplasts) Glucose Oxygen Carbon dioxide Cellular respiration (in mitochondria) Water for cellular work Heat energy CELLULAR RESPIRATION: AEROBIC HARVEST OF FOOD ENERGY:  Cellular respiration CELLULAR RESPIRATION: AEROBIC HARVEST OF FOOD ENERGY The main way that chemical energy is harvested from food and converted to ATP This is an aerobic process—it requires oxygen The Relationship Between Cellular Respiration and Breathing:  Cellular respiration and breathing are closely related Cellular respiration requires a cell to exchange gases with its surroundings Breathing exchanges these gases between the blood and outside air The Relationship Between Cellular Respiration and Breathing Slide17:  Figure 6.4 Breathing Lungs Muscle cells Cellular respiration The Overall Equation for Cellular Respiration:  A common fuel molecule for cellular respiration is glucose This is the overall equation for what happens to glucose during cellular respiration The Overall Equation for Cellular Respiration Unnumbered Figure 6.1 Glucose Oxygen Carbon dioxide Water Energy The Role of Oxygen in Cellular Respiration:  During cellular respiration, hydrogen and its bonding electrons change partners Hydrogen and its electrons go from sugar to oxygen, forming water The Role of Oxygen in Cellular Respiration Redox Reactions:  Chemical reactions that transfer electrons from one substance to another are called oxidation-reduction reactions Redox Reactions Redox reactions for short Slide21:  The loss of electrons during a redox reaction is called oxidation The acceptance of electrons during a redox reaction is called reduction Slide22:  Unnumbered Figure 6.2 [Oxygen gains electrons (and hydrogens)] Oxidation [Glucose loses electrons (and hydrogens)] Glucose Oxygen Carbon dioxide Water Reduction Slide23:  RS IS NECESSARY IN ALL LIVING CELLS. PLANTS ARE WELL KNOWN FOR PS, BUT THEY MUST ALSO REPIRE IN ORDER TO SURVIVE. PS - OCCURS ONLY IN PLANT CELLS CONTAINING CHLOROPHYLL DURING THE DAYLIGHT HOURS. RS - OCCURS IN ALL OF A PLANT’S LIVING CELLS 24 -7. Slide24:  PLANTS NEED ENERGY TO PERFORM MANY ESSENTIAL FUNCTIONS OF LIFE: GROWTH, REPAIR, NUTRIENT MOVEMENT, REPRODUCTION, & NUTRIENT TRANSPORT. WHY IS RS NECESSARY? The *Metabolic Pathway of Cellular Respiration:  Cellular respiration is an example of a metabolic pathway A series of chemical reactions in cells –building or degradation process All of the reactions involved in cellular respiration can be grouped into three main stages Glycolysis The Krebs cycle Electron transport * WHAT IS METABOLISM? The *Metabolic Pathway of Cellular Respiration A Road Map for Cellular Respiration:  A Road Map for Cellular Respiration Cytosol Mitochondrion High-energy electrons carried by NADH High-energy electrons carried mainly by NADH Glycolysis Glucose 2 Pyruvic acid Krebs Cycle Electron Transport Figure 6.7 Slide27:  Glycolysis Stage 1: Glycolysis:  Glycolysis breaks a six-carbon glucose into two three-carbon molecules These molecules then donate high energy electrons to NAD+, forming NADH A molecule of glucose is split into two molecules of pyruvic acid Stage 1: Glycolysis Slide29:  Figure 6.8 Glucose 2 Pyruvic acid Slide30:  Krebs Cycle Stage 2: The Krebs Cycle:  Stage 2: The Krebs Cycle The Krebs cycle completes the breakdown of sugar Slide32:  In the Krebs cycle, pyruvic acid from glycolysis is first “prepped” into a usable form, Acetyl-CoA Figure 6.10 CoA 1 2 3 Pyruvic acid Acetic acid Coenzyme A Acetyl-CoA (acetyl-coenzyme A) CO2 Slide33:  The Krebs cycle extracts the energy of sugar by breaking the acetic acid molecules all the way down to CO2 The cycle uses some of this energy to make ATP The cycle also forms NADH and FADH2 Slide34:  Figure 6.11 Input Acetic acid ADP 3 NAD FAD Krebs Cycle Output 2 CO2 1 2 3 4 5 6 Slide35:  Electron Transport Stage 3: Electron Transport:  Stage 3: Electron Transport Electron transport releases the energy your cells need to make the most of their ATP Slide37:  The molecules of electron transport chains are built into the inner membranes of mitochondria The chain functions as a chemical machine that uses energy released by the “fall” of electrons to pump hydrogen ions across the inner mitochondrial membrane These ions store potential energy Slide38:  Figure 6.12 Protein complex Electron carrier Inner mitochondrial membrane Electron flow Electron transport chain ATP synthase The Versatility of Cellular Respiration:  The Versatility of Cellular Respiration Cellular respiration can “burn” other kinds of molecules besides glucose Diverse types of carbohydrates Fats Proteins Slide40:  Figure 6.13 Food Polysaccharides Fats Proteins Sugars Glycerol Fatty acids Amino acids Amino groups Glycolysis Acetyl- CoA Krebs Cycle Electron Transport Adding Up the ATP from Cellular Respiration:  Adding Up the ATP from Cellular Respiration Figure 6.14 Cytosol Mitochondrion Glycolysis Glucose 2 Pyruvic acid 2 Acetyl- CoA Krebs Cycle Electron Transport by direct synthesis by direct synthesis by ATP synthase Maximum per glucose: FERMENTATION: ANAEROBIC HARVEST OF FOOD ENERGY:  FERMENTATION: ANAEROBIC HARVEST OF FOOD ENERGY Some of your cells can actually work for short periods without oxygen For example, muscle cells can produce ATP under anaerobic conditions Fermentation The anaerobic harvest of food energy Fermentation in Human Muscle Cells:  Human muscle cells can make ATP with and without oxygen They have enough ATP to support activities such as quick sprinting for about 5 seconds A secondary supply of energy (creatine phosphate) can keep muscle cells going for another 10 seconds To keep running, your muscles must generate ATP by the anaerobic process of fermentation Fermentation in Human Muscle Cells Slide44:  Glycolysis is the metabolic pathway that provides ATP during fermentation Pyruvic acid is reduced by NADH, producing NAD+, which keeps glycolysis going In human muscle cells, lactic acid is a by-product Slide45:  Figure 6.15a 2 ADP+ 2 Glycolysis Glucose 2 NAD 2 Pyruvic acid + 2 H 2 NAD 2 Lactic acid (a) Lactic acid fermentation Fermentation in Microorganisms:  Various types of microorganisms perform fermentation Yeast cells carry out a slightly different type of fermentation pathway This pathway produces CO2 and ethyl alcohol Fermentation in Microorganisms Slide47:  Figure 6.15b 2 ADP+ 2 2 ATP Glycolysis Glucose 2 NAD 2 Pyruvic acid 2 CO2 released + 2 H 2 NAD 2 Ethyl alcohol (b) Alcoholic fermentation Slide48:  The food industry uses yeast to produce various food products Figure 6.16 EVOLUTION CONNECTION: LIFE ON AN ANAEROBIC EARTH:  Ancient bacteria probably used glycolysis to make ATP long before oxygen was present in Earth’s atmosphere EVOLUTION CONNECTION: LIFE ON AN ANAEROBIC EARTH Glycolysis is a metabolic heirloom from the earliest cells that continues to function today in the harvest of food energy SUMMARY OF KEY CONCEPTS:  SUMMARY OF KEY CONCEPTS Chemical Cycling Between Photosynthesis and Cellular Respiration Visual Summary 6.1 Sunlight Heat Photosynthesis Cellular respiration Slide51:  The Overall Equation for Cellular Respiration Visual Summary 6.2 Oxidation: Glucose loses electrons (and hydrogens) Glucose Carbon dioxide Electrons (and hydrogens) Energy Oxygen Reduction: Oxygen gains electrons (and hydrogens) Slide52:  The Metabolic Pathway of Cellular Respiration Visual Summary 6.3 Glucose Oxygen Water Energy

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