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Author Topic:   Design Framework for Evolution
Panda
Member (Idle past 3739 days)
Posts: 2688
From: UK
Joined: 10-04-2010


Message 69 of 81 (699230)
05-16-2013 5:34 AM
Reply to: Message 68 by Genomicus
05-16-2013 1:09 AM


Hi Genomicus,
Genomicus writes:
"The most novel result of our analysis is seeing how, with minimal new material, evolution created the most important pathway of metabolism, achieving the best chemically possible design. In this case, a chemical engineer who was looking for the best design of the process [Krebs Cycle process] could not have found a better design than the cycle which works in living cells."
Source: The Puzzle of the Krebs Citric Acid Cycle: Assembling the Pieces of Chemically Feasible Reactions, and Opportunism in the Design of Metabolic Pathways During Evolution, 1996.
After reading that paper, I am unable to see how they justify the claim that a chemical engineer "could not have found a better design".
Could you maybe point me towards where they support that claim?
I suspect that it is in fact their wording that is confusing.
I think they perhaps would have been better writing "could not have found a better design using the material available."
Because the quote you provided seems to contradict their previous statement:
quote:
In the Krebs cycle problem the intermediary stages were also useful, but for different purposes, and, therefore, its complete design was a very clear case of opportunism.

"There is no great invention, from fire to flying, which has not been hailed as an insult to some god." J. B. S. Haldane

This message is a reply to:
 Message 68 by Genomicus, posted 05-16-2013 1:09 AM Genomicus has replied

Replies to this message:
 Message 70 by AZPaul3, posted 05-16-2013 8:13 AM Panda has seen this message but not replied
 Message 72 by Genomicus, posted 05-17-2013 10:02 PM Panda has replied

  
Panda
Member (Idle past 3739 days)
Posts: 2688
From: UK
Joined: 10-04-2010


Message 74 of 81 (699359)
05-17-2013 11:03 PM
Reply to: Message 72 by Genomicus
05-17-2013 10:02 PM


Genomicus writes:
The paper clearly explains how the Krebs Cycle is an optimal design based on the materials at hand, yet there is no reason to suppose the Krebs Cycle is not also optimal from an engineering standpoint. In other words, the statement that its design is a "very clear case of opportunism," does not, in itself, suggest that an engineer could construct a better Krebs Cycle.
I agree - but that simply means their statement is not relevant to AZPaul3's question:
AZPaul3 writes:
Is this the most efficient and effective way to break glucose into ATPs? With the evolutionary holdovers from pre-glucose and anaerobic processes I wouldn't think so, but then I'm not a biochemist.
Q: "Is this the most efficient and effective way to break glucose into ATPs?"
A: "It is the most efficient and effective way to break glucose into ATPs given the material to hand.
Do you see? It doesn't actually answer the question being asked.
(It is instead answering the question: "Is this the most efficient and effective way to break glucose into ATPs given the materials to hand?".)
As AZPaul3 says, there are inefficiencies in the Krebs Cycle.
But your quote doesn't address those inefficiencies.

"There is no great invention, from fire to flying, which has not been hailed as an insult to some god." J. B. S. Haldane

This message is a reply to:
 Message 72 by Genomicus, posted 05-17-2013 10:02 PM Genomicus has replied

Replies to this message:
 Message 75 by Genomicus, posted 05-18-2013 1:40 AM Panda has replied

  
Panda
Member (Idle past 3739 days)
Posts: 2688
From: UK
Joined: 10-04-2010


Message 76 of 81 (699379)
05-18-2013 9:11 AM
Reply to: Message 75 by Genomicus
05-18-2013 1:40 AM


Genomicus writes:
Yet I still do not see where exactly the inefficiencies lie. Merely because the Krebs Cycle uses parts in other systems does not make it inefficient. What part of the Krebs Cycle is inefficient, or a sub-optimal design?
Unfortunately, I cannot answer than question - my biological knowledge drops me off several streets before that destination.
But I assume it is what AZPaul3 is referring to here:
AZPaul3 writes:
With the evolutionary holdovers from pre-glucose and anaerobic processes...
This implies it has functionality that is no longer useful to a modern homo sapiens.
Hopefully others will provide some detail in to exactly how the Krebs Cycle is inefficient...
AZPaul3...it's your turn!

"There is no great invention, from fire to flying, which has not been hailed as an insult to some god." J. B. S. Haldane

This message is a reply to:
 Message 75 by Genomicus, posted 05-18-2013 1:40 AM Genomicus has seen this message but not replied

Replies to this message:
 Message 77 by AZPaul3, posted 05-18-2013 1:35 PM Panda has seen this message but not replied

  
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