When is ATP Made in the Body?
During a Process
called Cellular
Respiration that
takes place in
both Plants &
Animals &
Prokaryotes
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Cellular Respiration Overview
At this point life diverges into two forms and two
pathways
– Anaerobic cellular respiration (aka fermentation)
– Aerobic cellular respiration
Cellular Respiration Overview
• Transformation of chemical energy in food
into chemical energy cells can use: ATP
• Breakdown of one glucose can result in 36 ATP
molecules
Overall Reaction:
C6H12O6 + 6O2 → 6CO2 + 6H2O
Where Does Cellular Respiration
Take Place?
• It actually takes
place in two
parts of the cell:
Glycolysis occurs in
the Cytoplasm
Krebs Cycle & ETC
Take place in the
Mitochondria
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Glycolysis
Diagram
(page 128)
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Glycolysis Summary
-Takes place in the Cytoplasm (all cellsprokaryotes)
-Anaerobic (Doesn’t Use Oxygen)
-Glucose split into two molecules of
Pyruvate or Pyruvic Acid
-Requires input of 2 ATP
•Also produces 2 NADH and
4 ATP
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Fermentation
 Occurs when O2 NOT present (anaerobic)
Called LACTIC ACID FERMENTATION-in
muscle cells (makes muscles tired)
Called ALCOHOLIC FERMENTATION-in
yeast (produces ethanol)
Gains only 2 ATP from each Pyruvic acid
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Entering the MITOCHONDRIA
• Pyruvic acids ( 3 carbon atoms) from
glycolysis- turn into Acetyl CoA (2 carbon
atoms) as they enter the mitochondria.
• This produces 1 NADH each
Krebs Cycle
ATP
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NETS: 3NADH, 1ATP, 1FADH2, & 2CO2
Krebs Cycle
Step 1- Acetyl CoA combines with a 4 carbon
molecule to produce citric acid (6 carbons)
Kreb’s Cycle
Step 2- Carbon is removed (CO 2) and energy is
produced– NADH
Step 3-4 See step 2--- produces ATP and NADH
Kreb’s Cycle
• Step 5- Oxaloacetic acid is used to combine
with Acetyl CoA to restart the cycle
Krebs Cycle Summary
•
•
•
•
Requires Oxygen (Aerobic)
Completes the breakdown of glucose
Turns twice per glucose molecule
Therefore, For each Glucose molecule, the
Krebs Cycle produces 6NADH, 2FADH2, 4CO2,
and 2ATP
Takes place in matrix of mitochondria
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Electron Transport Chain (pg136)
Electron Transport Chain Summary
• Occurs Across Inner Mitochondrial
membrane
• FADH, and NADH donate electrons for the
chain
• NADH = 3 ATP’s
• FADH2 = 2 ATP’s
• Oxygen is the last electron acceptor and
combines with H+ to make water
• 34 ATP Produced
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Energy Tally
2 ATP for anaerobic vs 36 ATP for aerobic
– Glycolysis
2 ATP (anaerobic)
– Kreb’s
2 ATP
– Electron Transport
(aerobic)
34 ATP (aerobic)
38 ATP
• Anaerobic organisms can’t be too energetic but
are important for global recycling of carbon
CALORIE
• Defined as the amount of energy needed to
raise 1 gram of water 1 degree Celsius.
• 4.2 Joules
KILOCALORIES (Large Calorie) Food
Calorie
• 1 kilocalorie equals 1000 calories
• We measure food calories in the unit of
KILOCALORIES although we only call it a CALORIE.
• The complete oxidation of a glucose molecule will
yield 686 kcal.
• ATP requires 12 kcal to be formed
CALCULATING ENERGY YIELD
• EFFICIENCY of glycolysis =Energy Required to make ATP x 100
•
Total energy possible (686 kcal)
• Glycolysis is only 3.5 % efficient
• 2 ATP x 12 kcal x 100
• 686 kcal
CALCULATING ENERGY YIELD
Complete Aerobic Respiration is 66% efficient
38 ATP x 12 kcal x 100 =
686 kcal
66