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aerobic and anaerobic glucose degeneration in a cell

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aerobic and anaerobic glucose degeneration in a cell

Postby dancaqueen » Mon Jun 22, 2009 12:10 pm

Does anyone know anything on this: aerobic and anaerobic glucose degeneration in a cell
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Postby Jesse2504 » Tue Jun 23, 2009 3:43 am

If you are meaning the breakdown of glucose in a cell due to glycolysis I think you may have more luck finding information on such things =)

aerobic and anaerobic oxidation of glucose in a cell is referred to as glycolysis and is a method of energy production for nearly all organisms.

Aerobic refers to glycolysis in the presence of an electron acceptor and anaerobic refers to glycolysis without an electron acceptor.
Electron acceptors are referring to a molecule which the Electron Transport Chain can use.

In Anaerobic respiration/fermentation glucose is broken down through investment of ATP into several intermediates eventually creating pyruvate and 2 net ATP. Because of the lack of oxygen this reaction does not proceed to normal aerobic respiration in the mitochondria but instead continues to transform into other intermediates outside the mitochondria and produce the fermentation by-product. The main reason for this is to regenerate NAD+ from NADH and allow ATP production to continue without an electron acceptor required by the Electron Transport Chain. Two common by-products are lactic acid in muscles and ethanol (alcohol) in yeast.

In Aerobic respiration the same event occurs during glycolysis to create pyruvate but because of essential oxygen supplies the reaction can continue inside the mitochondria. When pyruvate enters the mitochondria it is oxidized into Acetyl CoA producing 2NADH and 2CO2. This is the starting point for the Krebs Cycle.
During the Krebs Cycle Acetyl CoA is bound to Oxaloacetate which is the last and most oxidized molecule to come out of the Krebs Cycle.
After this binding a reduced molecule Citrate is formed which is broken down into many intermediates producing 6NADH, 2GTP/2ATP, 2FADH2 and 2CO2
Once the molecule is fully oxidized to Oxaloacetate it is rebound to another Acetyl CoA and the cycle repeats.

The NADH and FADH2 molecules go to what is called the Electron Transport Chain (ETC) which makes use of the reduced state of these molecules to fuel the production of a proton gradient.
During this process NADH and FADH2 donate electrons to ETC Complex 1 and 2. Complex 1 uses the electrons to pump hydrogen ions (protons) across the cristae membrane creating a proton gradient. Ubiquinone (Q) transports these "spent" electrons from Complex 1 and 2 across the cristae membrane to Complex 3 which again uses them to create a proton gradient.
Cytochrome c shuffles these "spent" electrons to Complex 4 which uses them to create a proton gradient but also dumps these electrons onto Oxygen which combines with hydrogen ions to create water.

The proton gradient has created a high concentration of proton ions in the Intermembrane space. Due to diffusion which says that molecules move spontaneously from areas of high concentration to low concentration we can think of the proton gradient as having high potential energy.
The protein that utilizes this energy is called ATP Synthase and uses the proton motive force to drive the production of ATP, analagous to hydroelectric turbine that makes use of potential energy in water. The overall process leads to around 26ATP.

Hope that is what you were after!
Last edited by Jesse2504 on Tue Jun 23, 2009 6:47 pm, edited 1 time in total.
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"The most incomprehensible thing about the universe is that it is at all comprehensible" - Albert Einstein.
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Re: aerobic and anaerobic glucose degeneration in a cell

Postby dancaqueen » Tue Jun 23, 2009 3:43 pm

Thank you that really helps :)
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