Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential.

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


• Bacteria are used to produce yogurt, sour cream, pepperoni, and cheese

• Both carbon monoxide and cyanide kill by disrupting cellular respiration


• 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


• 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


• 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


• 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


• 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

• 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


• 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


• 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


• 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


• 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


• 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


Figure 6.3

Sunlightenergy

Ecosystem

Photosynthesis(in chloroplasts)

Glucose

Oxygen

Carbon dioxide

Cellular respiration(in mitochondria)

Water

for cellular work

Heat 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


• 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


Figure 6.4

Breathing

Lungs

Musclecells

Cellularrespiration


• 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


• 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


• Chemical reactions that transfer electrons from one substance to another are called oxidation-reduction reactions

Redox Reactions

– Redox reactions for short


• The loss of electrons during a redox reaction is called oxidation

• The acceptance of electrons during a redox reaction is called reduction


Unnumbered Figure 6.2

[Oxygen gains electrons (and hydrogens)]

Oxidation[Glucose loses electrons (and hydrogens)]

Glucose Oxygen Carbondioxide

Water

Reduction


• 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

Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential.

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