Transport of carbon dioxide to the lungs

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rambo
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Re: Trnasport of carbon dioxide to the lungs

Post by rambo » Sat Oct 29, 2005 10:57 am

Iftekhar wrote:Hey rambo! Thanks very much for that extra information. But, what really is this Krebs cycle? You said that after glycosis, pyruvic acid(what is pyruvic acid?) is broken down to CO2 or lactic acid and then CO2 is carried by the blood to the lungs and then diffuses onto areas of lower CO2 concentration. So, is this what is Krebs cycle? Please reply.

And, regarding your CO2 path, I think that your answer is correct because the path which you mentioned is the only simple path for the transport of CO2 to the lungs.

No the Krebs cycle is the process of cell respiration. It is also the second stage of an aerobic (process with oxygen) respiration. Glucose and oxygen are needed for this process to create ATP(Adenosine Tri phosphate), hydrogen is another big factor in making ATP later in the cytochrome process. After the sugar has been broken up we take the C 6 from C 6 H 12 O 6. The C 6 is then brought into the cell through the membrane and then split in half by enzymes in our cytoplasm, which releases a hydrogen also.Now, we have two pieces of C 3. Each piece is then called a pyruvic acid. This process is called glycolysis, the first stage. Then we go into the Krebs cycle where the C 3 enters the mitochondria. There, one carbon from C 3 is broken off from enzymes inside the mitochondria I believe. The C 2 is joined with C 4 to make it C 6 (citric acid). C 1 is broken down from the compound of C 6 then it joins oxygen to make CO 2 (an oxidized process). Another carbon is then broken down following the same process, releasing more CO 2. now to my understanding the first one uses ATP knocking a phosphate off adenosine, and the other adds one phosphate creating ATP. I'm not sure if one who reads this would like to respond for me to be sure? hydrogen is also broken off twice for each carbon being broken. Thus, C 4 is left ready to repeat the process joining with the next C 2. the hydrogen from glycolysis and Krebs cycle goes to the final stage which is cytochrome process.

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Post by rambo » Sat Oct 29, 2005 11:14 am

MrMistery wrote:Hi guys. I don't understand exactly what rambo meant but here is what really happens. 2 molecules of pyruvic acid(Ch3COCOOH) results in the anaerboic glycolys of one glucose molecule. From here it is transformed into Acetil~CoA and enters the Krebs cycle. The Krebs cycle, also reffered to as the citric acid cycle, is the sum of reactions from which you get your GTP, NADH and FADH2. This produces CO2 and is followed by oxidative fosforilation, which produces most of the ATP and needs Oxygen. Without oxigen present, pyruvic acid does not enter the cell, it is degraded anaerobicly into lactic acid(CH3CHOHCOOH-hope i got it right). This process does not release CO2

LOL.. U DIDNT UNDERSTAND IT BECAUSE MY FOCUS WAS NOT THE KREB CYCLE IT WAS THE CO 2. I MENTIONED THE KREB CYCLE BECAUSE ITS BY PRODUCTS IS CO 2 AND WATER. WHICH CO 2 WAS THEN THE SUBJECT, BUT GOOD JOB ANYWAY SMARTY PANTS. NEXT TIME U THINK U CAN TELL US IN ENGLISH...LOL JK I LIKE SCIENCE TERMINLOGY

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Post by rambo » Sat Oct 29, 2005 11:32 am

rambo wrote:If this helps I was studying the Krebs cycle and it mentioned how after glycolysis, in an anaerobic respiration process; the broken down pyruvic acid is broken down to co 2 or lactic acid. Following the path of the co 2 it exits the cell then travels through our blood, remember cells are located everywhere so veins are bringing co 2 from all parts of your body. so in this case I'm talking about foot muscle cells. After it enters your heart it is then forced back into the low concentrations of co 2 in the lung, diffusion. It is then ready to be exhaled from the body.

I BELIEVE OXYGEN IS NEEDED FOR THE PYRUVIC ACID TO DIFFUSE INSIDE THE MITOCHONDRIA. THEREFORE IN AN ANAEROBIC PROCESS GLYCOLYSIS WOULD BE THE LAST STEP. WHICH IS THE SPLITTING OF C 6. IT STILLS RELEASES HYDROGEN AT THIS POINT AND MAKES A NET GAIN OF 2 ATP. YET THE REMAINING MOLECULES JUST TURN INTO CO2 AND LACTIC ACID BECAUSE OF THE ABSENCE OF OXYGEN.

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Post by MrMistery » Sun Oct 30, 2005 11:02 am

What i meant is that in lactic fermentation(producing lactic acid from pyruvic acid in the absence of oxygen) there is no CO2 released.
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Post by mbmdphd_maybe » Mon Nov 07, 2005 6:35 pm

If I may, I might be able to clarify the statement about the carbonic acid rxn moving both directions.

Since carbonic acid is a weak acid, it dissociates in aqueous medium (which blood is), but not completely. The reaction looks like this:

CO2 + H2O <--> H2CO3 <--> (H+) + (CO3-)

Erythtrocytes contain an enzyme called carbonic anhydrase that performs several functions. Following the exchange of oxygen and carbon dioxide in the tissue beds, CA drives the rxn from the carbonic acid stage toward the dissociated ion stage:

...H2CO3 <-CA->> (H+) + (CO3-)

Once the acid is nearly dissociated, the CA activates a pump that pumps chloride ion into the erythrocyte while pumping bicarbonate (CO3-) out into the plasma. Upon reaching the lung, CA pumps Cl- back out and the bicarbonate back into the cell, and acts to drive the rxn in the exact opposite direction, facilitating diffusion of CO2 out of the bloodstream.

Does that help?

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