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Cellular Respiration

Chapter 9

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Interest Grabber

Feel the Burn

Do you like to run, bike, or swim? These all are good ways to exercise. When you exercise, your body uses oxygen to get energy from glucose,a six-carbon sugar.

Section 9-1

1. How does your body feel at the start of exercise, such as a long, slow run? How do you feel 1 minute into the run; 10 minutes into the run?

2. What do you think is happening in your cells to cause the changes in how you feel?

3. Think about running as fast as you can for 100 meters. Could you keep up this pace for a much longer distance? Explain.

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Section Outline

I. Chemical PathwaysA. Chemical Energy and Food

1. one gram of sugar glucose (C6H12O6) has 8311 calories2. calorie

a. The amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius

b. Food labels actually list kilocalories

Section 9-1

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B. Cellular Respiration

1. the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

Tertiary Consumers

Secondary Consumers

Primary Consumers

Producers

Energy Pyramid

Cellular Respiration

Photosynthesis

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2. Formulas

sugars + oxygen carbon dioxide + water

C6H12O6 + O2 CO2 + H2O 6 66

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Glucose

Glycolysis Krebs cycle

Electrontransport

Fermentation (without oxygen)

Alcohol or lactic acid

Chemical Pathways

Section 9-1

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C. Glycolysis

1. first set of reactions in cellular respiration

2. the process in which one molecule of glucose is broken in half producing two molecules of pyruvic acid

3. does not require oxygen

4. uses 2 ATP, but makes 4 ATP

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D. Fermentation

1. releases energy from food molecules by producing ATP in the absence of oxygen

2. anaerobic

a. Not in air – absence of oxygen

3. Two types of fermentation

a. Alcoholic fermentation

b. Lactic acid fermentation

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4. Alcoholic Fermentation

a. formula

Pyruvic + NADH alcohol + CO2 + NAD+

acid

b. Yeast making bread

c. Alcohol

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5. Lactic Acid Fermentationa. formula

Pyruvic + NADH lactic + CO2 + NAD+

acid acidb. this process regenerates NAD+ so that glycolysis can continuec. Heavy exercise – burningd. Cheese, yogurt, buttermilk, sour cream, pickles, sauerkraut, kimchi

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Section Outline

II. The Krebs Cycle and Electron Transport

A. Aerobic

1. in the presence of oxygen

B. Krebs Cycle

1. pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

Section 9-2

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Flowchart

Section 9-2

Glucose(C6H1206)

+Oxygen

(02)

GlycolysisKrebsCycle

ElectronTransport

Chain

Carbon Dioxide

(CO2)+

Water(H2O)

Cellular Respiration

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C. Electron Transport

1. the electron transport chain uses the high-energy electrons from the Krebs cycle to convert ADP into ATP

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D. The TOTALS

1. in the absence of oxygen/anaerobic – only 2 molecules of ATP are created

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2. 34 more ATP

molecules

are produced

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3. These 36 ATP molecules represent about 38% of the total energy of glucose

4. The cell is actually more efficient than a typical automobile burning gasoline

5. The other 62% is lost at heat

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E. Energy and Exercise

1. Quick Energy

a. Cells usually

contain enough

stored ATP for a

few seconds of intense exercise

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b. Then, ATP is produced via lactic acid fermentation which can produce enough ATP to last about 90 seconds

1) lactic acid builds up causing sore muscles

2) sprinters breathe heavy to replace the oxygen

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2. Long-Term Energy

a. Cellular respiration is the only way to get enough ATP for

exercise longer than 90 sec.

b. Energy is released slowly

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The end

Interest Grabber Answers

1. How does your body feel at the start of exercise, such as a long, slowrun? How do you feel 1 minute into the run; 10 minutes into the run?Students may answer that they feel no fatigue at the start of a run; however, after 1 minute and more so after 10 minutes, they are breathing hard, their heart rate has increased significantly, and their muscles may hurt.

2. What do you think is happening in your cells to cause the changesin how you feel?Students may say that the increase in heart rate and breathing rate are a response that gets extra oxygen to the cells. The pain may be attributed to the cells becoming fatigued.

3. Think about running as fast as you can for 100 meters. Could youkeep up this pace for a much longer distance? Explain your answer.Students may know that very high levels of performance can be sustained only very briefly even among the best of athletes. Students may say that the body runs out of readily available energy, food, or oxygen, or that the body builds up too many waste products in the cells.