phys question

[jesse14]

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Hello all,
I have a question and i cant seem to find the answer so maybe some of you might be able to help out a needy student 🙄

What happens in an cox defiency? (cox is an enzyme in the mito that oxidizes NADH to NAD). What happens when the NADH can't be oxidized in the mito and not enough NAD is made? what are the reprocussions of this?

Thank you!

 

[trudub]

Look up Kearns Sayre. Cytochrome c oxidase mutation is the most frequent cuase of Kearns Sayre syndrome.

 

[jesse14]

Look up Kearns Sayre. Cytochrome c oxidase mutation is the most frequent cuase of Kearns Sayre syndrome.

thanx for the reply but im not sure that answers my question..... i just want to know the main effects of a cox deficiency

 

[Krazykritter]

If you tie up available NAD as NADH you do not have electron receptors that can be transferred to ETC. If you cannot transfer your electron to the ETC you lose much of your ability to generate ATP. I don't know the exact symptoms, but anything associated w/ lack of energy production would make sense to me.

Hope this helps

 

[tupac_don]

Hello all,
I have a question and i cant seem to find the answer so maybe some of you might be able to help out a needy student 🙄

What happens in an cox defiency? (cox is an enzyme in the mito that oxidizes NADH to NAD). What happens when the NADH can't be oxidized in the mito and not enough NAD is made? what are the reprocussions of this?

Thank you!

I think you are confusing things, there is no enzyme cox in mitochondria, its used for prostaglanding synthesis. You will die, b/c you need NAD+ for starting up rxns and if you can't run NADH thru the ETC to make ATP you will die unless this can be circumvented.

 

[tupac_don]

thanx for the reply but im not sure that answers my question..... i just want to know the main effects of a cox deficiency

Yea if you block cytochrome c oxidase aka Complex IV with something like cyanide, carbon monoxide or have def (which I haven't heard of) you die. B/c it is the terminal acceptor of e's before it transfers it to O2 so it cannot be circumvented like earlier steps. Hope this helps.

 

[jesse14]

I think you are confusing things, there is no enzyme cox in mitochondria, its used for prostaglanding synthesis. You will die, b/c you need NAD+ for starting up rxns and if you can't run NADH thru the ETC to make ATP you will die unless this can be circumvented.

ummm, im pretty sure there is cox enzyme in the mito. Its on the very last cytochrome in the ETC.
here's a link to varify my thoughts : http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8381519&dopt=Abstract

But as to the other responce... how exactly does NAD create ATP? I have the notes in frontr of me but when someone else types in in different words i always seem to understand it,
From what i know... NADH has to be broken down into NAD by LDH. This causes H+ and electrons to be shuttlled into the mito to go through the ETC.. then a P is added to the incoming ADP to create ATP.... i'm missing some steps in between lol.. HELP please!

 

[jesse14]

I think you are confusing things, there is no enzyme cox in mitochondria, its used for prostaglanding synthesis. You will die, b/c you need NAD+ for starting up rxns and if you can't run NADH thru the ETC to make ATP you will die unless this can be circumvented.

ummm, im pretty sure there is cox enzyme in the mito. Its on the very last cytochrome in the ETC.
here's a link to varify my thoughts : http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8381519&dopt=Abstract

But as to the other responce... how exactly does NAD create ATP? I have the notes in front of me but when someone else types it in different words i always seem to understand it,
From what i know... NADH has to be broken down into NAD by LDH. This causes H+ and electrons to be shuttlled into the mito to go through the ETC.. then a P is added to the incoming ADP to create ATP.... i'm missing some steps in between lol.. HELP please!

 

[Krazykritter]

NAD transfers its electrons that it is carrying when it is in the form of NADH to the ETC. It then transfers it to the specific part of the ETC. The electron is then shuttled through the rest of the complex to generate a proton gradient. The gradient is then used to drive ATP Synthase which using Oxygen (making h2O) as a final receptor for the electrons donated to it by electron carriers such as NAD and FAD.

That should help.

 

[jesse14]

NAD transfers its electrons that it is carrying when it is in the form of NADH to the ETC. It then transfers it to the specific part of the ETC. The electron is then shuttled through the rest of the complex to generate a proton gradient. The gradient is then used to drive ATP Synthase which using Oxygen (making h2O) as a final receptor for the electrons donated to it by electron carriers such as NAD and FAD.

That should help.

Thanks Krayj36, that does help!
But i'm still not exactly sure how the incoming ADP manages to get a P to become ATP?? Does ATP synthase provide the ADP with the P to become ATP?

 

[Perrin]

NAD transfers its electrons that it is carrying when it is in the form of NADH to the ETC. It then transfers it to the specific part of the ETC. The electron is then shuttled through the rest of the complex to generate a proton gradient. The gradient is then used to drive ATP Synthase which using Oxygen (making h2O) as a final receptor for the electrons donated to it by electron carriers such as NAD and FAD.

That should help.

Not quite correct. The electrons are transferred to cyt c oxidase which transfers the electrons to O2 and uses H's in the mito to make water. The proton gradient across the inner mito membrane drives ATP synthase. As the protons move through ATP synthase into the mito matrix, ATP synthase brings ADP and Pi together to form ATP.


The cox you are referring to is cytochrome c oxidase (cox) which makes water using the electrons. ATP synthase doesn't make water, just ATP.

 

[tupac_don]

ummm, im pretty sure there is cox enzyme in the mito. Its on the very last cytochrome in the ETC.
here's a link to varify my thoughts : http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8381519&dopt=Abstract

But as to the other responce... how exactly does NAD create ATP? I have the notes in frontr of me but when someone else types in in different words i always seem to understand it,
From what i know... NADH has to be broken down into NAD by LDH. This causes H+ and electrons to be shuttlled into the mito to go through the ETC.. then a P is added to the incoming ADP to create ATP.... i'm missing some steps in between lol.. HELP please!

I think confusion occurred b/c cox is not an official abreviation for this enzyme. I dont' think many people refer to that enzyme as cox enzyme but rather as cytochrome oxidase or Complex IV. There is an enzyme in prostaglanding synthesis that is actually referred to as COX enzyme which is inhibited by NSAID"s and that's why the confusion occurred.

And yea, this should be pretty much in any textbook, but since this is the last enzyme in the chain, before giving electrons to oxygen if its blocked or missing, you are gonna die.

 

[coffeeluver]

Thanks Krayj36, that does help!
But i'm still not exactly sure how the incoming ADP manages to get a P to become ATP?? Does ATP synthase provide the ADP with the P to become ATP?

ADP is transported via an antiport sytem. As ATP is transported out of the mito, ADP is transported in. As the others said, as protons diffuse down their concentration back into the matrix, this creates a conformational change in the ATP synthase which drives the formation of ATP from ADP and inorganic phosphate in the mito.

 

[werd]

just to point it out, there is confusion here because cox usually refers to cyclo-oxygenase but it's being used here for cytochrome-c oxidase. i'm not familiar with the effects cyt-c ox deficiency... with none you'd probably die; deficiencies of those kind of mito complexes usually results in some sort of neuro disease, but i'd just look it up on medline or even google.