Tracking Oxygen in Cellular Respiration

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
lorax
Garter
Garter
Posts: 2
Joined: Mon Jan 16, 2006 12:13 pm

Tracking Oxygen in Cellular Respiration

Post by lorax » Mon Jan 16, 2006 12:22 pm

From examining Biology textbooks, it seems that one end product of electron transport is water molecules made from hydrogens and oxygen gas.

From a single glucose, 6 H2O molecules are made and only 3 O2 molecules (6 O atoms total) are required for ETS.

Yet to create a balanced equation you need 6 O2's. Why can't I figure out from the diagrams where the other three O2 molecules go?

THANKS!

User avatar
victor
King Cobra
King Cobra
Posts: 2668
Joined: Sat Apr 30, 2005 12:01 pm
Location: Yogyakarta, Indonesia..
Contact:

Post by victor » Mon Jan 16, 2006 1:32 pm

where's the CO2??
C6H12O6 + 6O2 -> 6CO2 + 6H2O
Q: Why are chemists great for solving problems?
A: They have all the solutions.

lorax
Garter
Garter
Posts: 2
Joined: Mon Jan 16, 2006 12:13 pm

Where does the oxygen enter?

Post by lorax » Mon Jan 16, 2006 5:06 pm

I am not sure this answers my question.

I see where the oxygen ends up but no diagram I ever remember seeing, including several current Advanced Placement Biology books, shows oxygen gas entering any steps of cellular respiration reaction except the final step of electron transport. And as explained earlier, this only accounts for half the oxygen atoms. Does it enter the Kreb Cycle or Glycolysis or that step in between with no name somewhere? Obviuosly it must, but why can't I find it in the diagrams?

thanks!

User avatar
victor
King Cobra
King Cobra
Posts: 2668
Joined: Sat Apr 30, 2005 12:01 pm
Location: Yogyakarta, Indonesia..
Contact:

Post by victor » Wed Jan 18, 2006 1:09 pm

No, glycolysis and Krebs are anaerobic respiration process....the pathway that uses O2 molecules is ETS....so I can say that O2 molecules must've enter that stage...
Q: Why are chemists great for solving problems?
A: They have all the solutions.

User avatar
Dr.Stein
King Cobra
King Cobra
Posts: 3501
Joined: Thu Jul 07, 2005 7:58 am
Location: 55284 Yogyakarta, Indonesia
Contact:

Post by Dr.Stein » Thu Jan 19, 2006 5:11 am

Hey glycolysis can be both aerobic and anaerobic :twisted:

"Under aerobic conditions, the dominant product in most tissues is pyruvate and the pathway is known as aerobic glycolysis. When oxygen is depleted, as for instance during prolonged vigorous exercise, the dominant glycolytic product in many tissues is lactate and the process is known as anaerobic glycolysis"
Image

User avatar
Poison
Inland Taipan
Inland Taipan
Posts: 2322
Joined: Sun Jan 02, 2005 12:44 pm
Location: Turkey

Post by Poison » Thu Jan 19, 2006 7:12 am

victor wrote:No, glycolysis and Krebs are anaerobic respiration process....the pathway that uses O2 molecules is ETS....so I can say that O2 molecules must've enter that stage...


Hey, glycolysis happens in both aerobic and anaerobic conditions. ETS and Krebs happens in aerobic conditions. :)
It matters not how strait the gate
How charged with punishment the scroll
I am the Master of my fate
I am the Captain of my soul.

User avatar
Dr.Stein
King Cobra
King Cobra
Posts: 3501
Joined: Thu Jul 07, 2005 7:58 am
Location: 55284 Yogyakarta, Indonesia
Contact:

Post by Dr.Stein » Thu Jan 19, 2006 8:29 am

I think Victor was asleep when he wrote his post :lol:
Image

User avatar
victor
King Cobra
King Cobra
Posts: 2668
Joined: Sat Apr 30, 2005 12:01 pm
Location: Yogyakarta, Indonesia..
Contact:

Post by victor » Thu Jan 19, 2006 1:15 pm

No, I'm fully awake....what I mean anaerobic is Glycolysis and Krebs do not use Oxygen molecule as the final electron acceptor but they use NADH+H and FADH2....
Q: Why are chemists great for solving problems?
A: They have all the solutions.

User avatar
Poison
Inland Taipan
Inland Taipan
Posts: 2322
Joined: Sun Jan 02, 2005 12:44 pm
Location: Turkey

Post by Poison » Thu Jan 19, 2006 7:44 pm

Yes, you are right but, it can be understood differently.
It matters not how strait the gate
How charged with punishment the scroll
I am the Master of my fate
I am the Captain of my soul.

User avatar
MrMistery
Inland Taipan
Inland Taipan
Posts: 6832
Joined: Thu Mar 03, 2005 10:18 pm
Location: Romania(small and unimportant country)
Contact:

Post by MrMistery » Thu Jan 19, 2006 8:12 pm

I have to agree with Dr.Stein victor on the Krebs cycle. Although the reactions of the Krebs cycle do not require oxygen, the Krebs cycle is aerobic- it only takes place when oxygen is present. Because it would be useless to have krebs cycle when there is no oxygen present, the cell has developed a way to use oxygen as an information source- it is required for pyruvate to enter the mithocondrion matrix

Dr.Stein wrote:"Under aerobic conditions, the dominant product in most tissues is pyruvate and the pathway is known as aerobic glycolysis. When oxygen is depleted, as for instance during prolonged vigorous exercise, the dominant glycolytic product in many tissues is lactate and the process is known as anaerobic glycolysis"


Where did you take this from, a high-school textbook? Cause this is exactly the kind of thing they state in our books. :roll: :roll: :roll:
Now, glycolysis produces 2 molecules of pyruvate, 2 molecules of ATP and 2 molecules of NADH. When there is no oxygen present, the cell can't simply stop it's activity, it has to keep producing energy, even if that means doing it only by glycolysis. But, in order to do so, it needs fresh molecules of NAD+ in order to get from stage 5 to stage 6. The way it does this is by recycling the useless NADH molecules, by adding protons and electrons to pyruvic acid, turning it into lactic acid
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

User avatar
Poison
Inland Taipan
Inland Taipan
Posts: 2322
Joined: Sun Jan 02, 2005 12:44 pm
Location: Turkey

Post by Poison » Thu Jan 19, 2006 8:33 pm

Yep. That is what I was trying to say. saying Krebs is anaerobic (or similar things) is wrong according to the terms we use.
It matters not how strait the gate
How charged with punishment the scroll
I am the Master of my fate
I am the Captain of my soul.

User avatar
Dr.Stein
King Cobra
King Cobra
Posts: 3501
Joined: Thu Jul 07, 2005 7:58 am
Location: 55284 Yogyakarta, Indonesia
Contact:

Post by Dr.Stein » Fri Jan 20, 2006 6:47 am

MrMistery wrote:Where did you take this from, a high-school textbook? Cause this is exactly the kind of thing they state in our books. :roll: :roll: :roll:

Just a copy-paste from my slides 8)
Image

Post Reply

Who is online

Users browsing this forum: No registered users and 5 guests