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9-2 Aerobic Respiration
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Glycolysis
Glycolysis Review: Occurs in cytoplasm
C6H12O6 + 2 NAD+ → 2 Pyruvic Acid + 2 ATP + 2 NADH
2 ATP
2 ADP
4 ADP
4 ATP
Glycolysis is the first stage in cellular respiration. During glycolysis, glucose is broken down into 2 molecules of pyruvic acid.
Glucose
2NAD+
2 Pyruvic
acid 2
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3. 9-2 The Krebs Cycle and Electron Transport
Glycolysis is always the 1st step of Cellular Respiration.
If Oxygen can be used, the 2nd step is called AEROBIC RESPIRATION. = 2 parts
1 = Krebs Cycle
2 = Electron Transport Chain.
Happens in the mitochondria
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Mitochondria
Aerobic Respiration occurs inside a Mitochondria!
Inner Membrane Space
Outer membrane
Inner membrane
Matrix
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The Krebs Cycle
The Krebs Cycle
Occurs in the Mitochondrial Matrix.
Pyruvic acid from Glycolysis enters the mitochondria.
Inner membrane space
Outer membrane
Inner membrane
Matrix
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The Krebs Cycle
What happens during the Krebs cycle?
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The Krebs Cycle
During the Krebs cycle, Pyruvic Acid is broken down so more energy can be released. CO2 is also produced.
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The Krebs Cycle
The Krebs cycle begins when pyruvic acid produced by glycolysis enters the mitochondrion.
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The Krebs Cycle
One carbon molecule is removed, forming CO2, and electrons are removed, changing NAD+ to NADH.
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The Krebs Cycle
Coenzyme A joins the 2-carbon molecule, forming acetyl-CoA.
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The Krebs Cycle
Acetyl-CoA then adds the 2-carbon acetyl group to a 4-carbon compound, forming citric acid.
Citric acid
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The Krebs Cycle
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Citric acid is broken down into a 5-carbon compound, then into a 4-carbon compound.
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The Krebs Cycle
Two more molecules of CO2 are released and electrons join NAD+ and FAD, forming NADH and FADH2.
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The Krebs Cycle
In addition, one molecule of ATP is generated.
The complete breakdown of glucose through cellular respiration, including glycolysis, results in the production of 36 molecules of ATP.
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The Krebs Cycle
The Kreb’s Cycle- What do you need to know?
2nd step of Aerobic Respiration- (1st is Glycolysis)
Occurs in Mitochondrial Matrix.
Takes Pyruvic Acid from Glycolysis and makes:
CO2 = a waste product
Only 2 ATP &
8 NADH &
2 FADH2
NADH & FADH2 are electron carriers, they are important in the next step!
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Electron Transport
Electron Transport – just like photosynthesis, except backwards!!!
The electron transport chain uses the high- energy electrons from Glycolysis and the Krebs cycle to make a concentration gradient and create ATP.
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Electron Transport
NADH and FADH2 carry electrons TO the ETC where they are passed along the electron transport chain from one carrier protein to the next.
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Electron Transport
The energy the electrons have are used to pump H+ ions out of the matrix and into the inner membrane space.
Inner membrane space
Matrix
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Electron Transport
A High Concentration is created inside the innermembrane space. A Low Concentration is created inside the matrix.
Inner membrane space
Matrix
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Electron Transport
The H+ ions move through the ATP Synthase from High to Low Concentration causing the ATP Synthase to spin.
Channel
ATP synthase
The electron transport chain uses high-energy electrons from the Krebs cycle to convert ADP to ATP.
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Electron Transport
This movement provides energy to turn ADP into ATP!
Channel
ATP synthase
The electron transport chain uses high-energy electrons from the Krebs cycle to convert ADP to ATP.
ATP
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Electron Transport
At the end of the chain, Oxygen removes the electrons from the ETC so it can keep running.
WHY YOU NEED TO BREATHE!!!!!!
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Electron Transport
Oxygen allows more electrons to move, to make a concentration gradient so more ATP can be created.
If your cells don’t get enough oxygen they die from lack of ATP, not lack of oxygen!
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The Totals
The Totals: Per 1 Glucose
Glycolysis: 2 ATP
Krebs Cycle: 2 ATP
ETC: 32 ATP
AEROBIC RESPIRATION TOTAL = 36 ATP
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9-2
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9-2
The Krebs cycle breaks pyruvic acid down into
oxygen.
NADH.
carbon dioxide.
alcohol.
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9-2
What role does the Krebs cycle play in the cell?
It breaks down glucose and releases its stored energy.
It releases energy from molecules formed during glycolysis.
It combines carbon dioxide and water into high-energy molecules.
It breaks down ATP and NADH, releasing stored energy.
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9-2
In eukaryotes, the electron transport chain is located in the
cell membrane.
inner mitochondrial membrane.
cytoplasm.
outer mitochondrial membrane.
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9-2
To generate energy over long periods, the body must use
stored ATP.
lactic acid fermentation.
cellular respiration.
glycolysis.
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9-2
Which statement correctly describes photosynthesis and cellular respiration?
Photosynthesis releases energy, while cellular respiration stores energy.
Photosynthesis and cellular respiration use the same raw materials.
Cellular respiration releases energy, while photosynthesis stores energy.
Cellular respiration and photosynthesis produce the same products.
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31. END OF SECTION