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a. ATP yield of aerobic respiration is contingent on adequate supply of __, without which __ would cease
i. This is solved by __= without oxygen
1. Distinction between the two: __
- oxygen
- oxidative phosphorylation
- fermentation and anaerobic respiration
- ETC used in anaerobic, not fermentation
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a. Anaerobic Respiration
i. Takes place in certain prokaryotes that live without oxygen
1. __is used, but instead of oxygen as final acceptor, __, __, can do the job
a. Instead of __as byproduct, other substance produced, such as H2S
- ETC
- other electronegative substances;such as sulfate ion
- H2O
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a. Fermentation: __+ reactions that __ by __ to __
- glycolysis
- regenerate NAD+
- transferring electrons from NADH
- pyruvate or its derivatives
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i. Harvests energy without __or __
1. Glycolysis oxidizes glucose to __a. Oxidizing agent of glycolysis is __
b. It is __, and some of the energy made available makes ATP through __
c. Glycolysis generates __ regardless of oxygen’s presence
- oxygen
- ETC
- two molecules of pyruvate
- NAD+
- exergonic
- substrate-level phosphorylation
- two ATP
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i. It is an extension of glycolysis that allows continuous generation of ATP by the __
1. There must be a sufficient supply of__ to accept electrons during the __ step of glycolysis
a. Without recycling of NAD+ from NADH, what would happen?
- substrate-level phosphorylation of glycolysis
- NAD+
- oxidation
- glycolysis would reduce all NAD+, depleting its pool, and shut itself down
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Types of Fermentation
alcohol and lactic acid fermentation
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Explain alcohol fermentation
- Pyruvate--> ethanol in two steps
- 1: release of CO2 from pyruvate, which is converted to acetaldehyde
- 2: acetaldehyde reduced by NADH to ethanol, regenerating NAD+
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Explain lactic acid fermentation
pyruvate reduced directly by NADH to form lactate with no CO2 release
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a. Humans do __when oxygen is scarce
i. Exercise
ii. Excess lactase is carried by blood to __, where its converted __
- lactic acid fermentation
- liver
- back to pyruvate
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Comparison of Fermentation with Anaerobic and Aerobic REspiration
- 1. All three use glycolysis to oxidize glucose and other organic fuels to pyruvate, producing two ATP by substrate level phosphorylation
- 2. NAD+ is oxidizing agent
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Contrast: __
1. Contrasting mechanisms for oxidizing NADH back to NAD+
- a. F: final electron acceptor is organic molecule, such as pyruvate or acetaldehyde
- b. CR: electrons in NADH transferred to ETC, where they move down to a final electron acceptor
- - Aerobic: oxygen/ Anaerobic: electronegative molecule
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The passage of electrons down an ETC allows __?
ATP production and NAD+ regeneration and more ATP from oxidation of pyruvate iin the mitochondria
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Without an ETC, what is up?
energy stored in pyruvate is unavailable
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i. Cellular Respiration harvests more energy than fermentation (__x more)
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Types of Organisms:
Obligate anaerobes: __
1. Carry out only fermentation or anaerobic respiration and can’t survive in presence of oxygen
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Types of Organisms:
Facultative anaerobes:__
- 1. carry out only aerobic oxidation of pyruvate, not fermentation or respiration (cells of the brain)
- a. muscle cells can do this
- i. pyruvate is a fork in the road that has two ways
- 1. aerobic: pyruvateà acetyl CoAà CAC
- 2. anaerobic: lactic acid fermentation
- a. pyruvate becomes electron acceptor to recycle NAD+
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a. Evolution
i. __is evolutionary
1. Ancient prokaryotes used __before oxygen was present
2. It evolved with presence of __
3. Location in __implies great antiquity because it doesn’t require membrane
- Glycolysis
- glycolysis
- oxygen
- cytosol
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