Cellular Respiration
Chapter 9
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Section:
Interest Grabber
Section 9-1
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.
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
Section 9-1
I. Chemical Pathways
A. Chemical Energy and Food
1. one gram of sugar glucose (C6H12O6)
has 8311 calories
2. 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
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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
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Energy Pyramid
Tertiary Consumers
Cellular
Respiration
Secondary Consumers
Primary Consumers
Photosynthesis
Producers
2. Formulas
sugars + oxygen
C6H12O6 + 6 O2
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carbon dioxide + water
6 CO2 + 6 H2O
Chemical Pathways
Section 9-1
Glucose
Glycolysis
Krebs
cycle
Fermentation
(without oxygen)
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Electron
transport
Alcohol or
lactic acid
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 Fermentation
a. formula
Pyruvic + NADH  lactic + CO2 + NAD+
acid
acid
b. this process regenerates NAD+ so
that glycolysis can continue
c. Heavy exercise – burning
d. Cheese, yogurt, buttermilk, sour
cream, pickles, sauerkraut, kimchi
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Section:
Section Outline
Section 9-2
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 energyextracting reactions
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Section:
Flowchart
Section 9-2
Cellular Respiration
Glucose
(C6H1206)
+
Glycolysis
Oxygen
(02)
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Section:
Krebs
Cycle
Carbon
Dioxide
Electron
(CO2)
Transport
+
Chain
Water
(H2O)
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
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Interest Grabber Answers
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?
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 changes
in 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 you
keep 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.