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Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
PowerPoint® Lecture Slides for Essential Biology, Second Edition & Essential Biology with Physiology
Neil Campbell, Jane Reece, and Eric Simon
Presentation prepared by Chris C. Romero
CHAPTER 6CHAPTER 6
Cellular Respiration: Harvesting Chemical EnergyFigures 6.1 – 6.5
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• Bacteria are used to produce yogurt, sour cream, pepperoni, and cheese
• Both carbon monoxide and cyanide kill by disrupting cellular respiration
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 6.3
Sunlightenergy
Ecosystem
Photosynthesis(in chloroplasts)
Glucose
Oxygen
Carbon dioxide
Cellular respiration(in mitochondria)
Water
for cellular work
Heat energy
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 6.4
Breathing
Lungs
Musclecells
Cellularrespiration
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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 Carbondioxide
Water Energy
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• Chemical reactions that transfer electrons from one substance to another are called oxidation-reduction reactions
Redox Reactions
– Redox reactions for short
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• The loss of electrons during a redox reaction is called oxidation
• The acceptance of electrons during a redox reaction is called reduction
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
Unnumbered Figure 6.2
[Oxygen gains electrons (and hydrogens)]
Oxidation[Glucose loses electrons (and hydrogens)]
Glucose Oxygen Carbondioxide
Water
Reduction
Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings
• Why does electron transfer to oxygen release energy?
– When electrons move from glucose to oxygen, it is as though they were falling
– This “fall” of electrons releases energy during cellular respiration
Figure 6.5
Releaseof heatenergy