Question for a Creationist Biologist

[joeferrari15]

This is a question for a biologist (or someone with a good understanding of biology) who is also a creationist. But, so that everyone can get the jist of the argument, I will do my best to explain everything.
Starting with some background:

Photosynthesis is the process by which plants, and some animals, make food in the form of glucose typically from sunlight, CO2, and water. Photosynthesis has two main parts:


1) Light reactions: light energy is used to split H2O into H+ (protons) and O2, and to use those protons to make energy (in the form of ATP and NADPH).

This energy is then used to power the second part of photosynthesis,

2) The Calvin Cycle: Basically constructs sugar from CO2 in a number of steps, which I will not cover.

The first part of the Calvin Cycle is Carbon Fixation, where the CO2 is attached to RuBP, a five-carbon sugar, by an enzyme called Ribulose-Biphosphate Carboxylase, or Rubisco.
CO2 attaches to the active site (a part of an enzyme) and is then attached to RuBP. However, O2 is also a good fit for the active site of Rubisco. In fact, O2 is a better fit than CO2, and therefore is a competitive inhibitor; that is, Rubisco will accept O2 before CO2.
When O2 gets to rubisco first, bad things happen for the plant. Instead of making a 6-carbon sugar as it should, the mistaken rubisco will actually cause the 5-carbon sugar to split into a 3- and 2-carbon sugar. The 2-carbon sugar is useless, and is exported from the chloroplast. This process of mistaken substrate is called photorespiration, and is bad for plants because it depletes its stores of starch.

But why does rubisco accept the oxygen, when that leads to disaster for the plant? Well, according to modern theory, it is evolutionary baggage. When rubisco first came around about 1.5 Billion years ago, there wasn't much oxygen in the atmosphere. Therefore, it didn't really matter whether or not rubisco accepted O2 at all, much less over CO2.

This all leads to my question:

What is the creationist reason for rubisco's flaw?

-Joe

*EDIT*
For clarification, rubisco's flaw is that it has a higher affinity for O2 than CO2, thus causing the problem of photorespiration.

 

[busterdog]

This all leads to my question:

What is the creationist reason for rubisco's flaw?

-Joe

Flaw? Not so's you'd notice. The plants are getting along quite well from what I can see.

(That means, I have no idea.)

 

[MatthewDiscipleofGod]

I'll let Rick who has a Ph. D. in plant breeding and genetics at the University of Missouri Columbia answer this one.
Shining light on the evolution of photosynthesis

This is a question for a biologist (or someone with a good understanding of biology) who is also a creationist. But, so that everyone can get the jist of the argument, I will do my best to explain everything.
Starting with some background:

Photosynthesis is the process by which plants, and some animals, make food in the form of glucose typically from sunlight, CO2, and water. Photosynthesis has two main parts:


1) Light reactions: light energy is used to split H2O into H+ (protons) and O2, and to use those protons to make energy (in the form of ATP and NADPH).

This energy is then used to power the second part of photosynthesis,

2) The Calvin Cycle: Basically constructs sugar from CO2 in a number of steps, which I will not cover.

The first part of the Calvin Cycle is Carbon Fixation, where the CO2 is attached to RuBP, a five-carbon sugar, by an enzyme called Ribulose-Biphosphate Carboxylase, or Rubisco.
CO2 attaches to the active site (a part of an enzyme) and is then attached to RuBP. However, O2 is also a good fit for the active site of Rubisco. In fact, O2 is a better fit than CO2, and therefore is a competitive inhibitor; that is, Rubisco will accept O2 before CO2.
When O2 gets to rubisco first, bad things happen for the plant. Instead of making a 6-carbon sugar as it should, the mistaken rubisco will actually cause the 5-carbon sugar to split into a 3- and 2-carbon sugar. The 2-carbon sugar is useless, and is exported from the chloroplast. This process of mistaken substrate is called photorespiration, and is bad for plants because it depletes its stores of starch.

But why does rubisco accept the oxygen, when that leads to disaster for the plant? Well, according to modern theory, it is evolutionary baggage. When rubisco first came around about 1.5 Billion years ago, there wasn't much oxygen in the atmosphere. Therefore, it didn't really matter whether or not rubisco accepted O2 at all, much less over CO2.

This all leads to my question:

What is the creationist reason for rubisco's flaw?

-Joe

*EDIT*
For clarification, rubisco's flaw is that it has a higher affinity for O2 than CO2, thus causing the problem of photorespiration.

 

[joeferrari15]

I'll let Rick who has a Ph. D. in plant breeding and genetics at the University of Missouri Columbia answer this one.
Shining light on the evolution of photosynthesis

Thank you for the article.

However, it does not discuss the flaw of rubisco, only the creationist reasoning of how it is constructed and how it works.

 

[MatthewDiscipleofGod]

What if there really isn't a flaw? Just like there isn't such a thing as vestigtial organs.

Thank you for the article.

However, it does not discuss the flaw of rubisco, only the creationist reasoning of how it is constructed and how it works.

 

[joeferrari15]

The debate isn't whether or not rubisco has a flaw--it does; accepting O2 over CO2 and causing photorespiration is a flaw. The question is how a creationist would explain how it came about.

 

[MatthewDiscipleofGod]

To be honest with you I don't know much about the rubisco so I won't agree that there is or is not a flaw. That is why I mentioned vestigtial organs. Many scientists still believe in them because they are stuck in the framework of evolution. I just wanted to caution that the view about the flaw with rubisco could be the same thing.

Generally speaking though there are a lot of flaws in the world. The core cause of that would be the fall in the Garden. I believe it would be fascinating to study plants and animals in the garden before sin. Adam could have done that with dinosaurs, lions and other animals. It's hard to understand these things in a fallen world but when it comes to things in the past it always boils down to who will you put your trust in. We were not there but we do know someone who was and did record it for us in a historical context.

The debate isn't whether or not rubisco has a flaw--it does; accepting O2 over CO2 and causing photorespiration is a flaw. The question is how a creationist would explain how it came about.

 

[joeferrari15]

To be honest with you I don't know much about the rubisco so I won't agree that there is or is not a flaw. That is why I mentioned vestigtial organs. Many scientists still believe in them because they are stuck in the framework of evolution. I just wanted to caution that the view about the flaw with rubisco could be the same thing.

Generally speaking though there are a lot of flaws in the world. The core cause of that would be the fall in the Garden. I believe it would be fascinating to study plants and animals in the garden before sin. Adam could have done that with dinosaurs, lions and other animals. It's hard to understand these things in a fallen world but when it comes to things in the past it always boils down to who will you put your trust in. We were not there but we do know someone who was and did record it for us in a historical context.

Hmm...

I understand that you don't have an understanding of rubisco...Its not exactly headline news (the rubisco, I mean). But I have trouble accepting that enzymes involved in photosynthesis are flawed because of man's fall from grace.

I don't know. Perhaps this was the wrong forum to present this question. But if there are any biologists out there that understand the dilemma and could give me the creationist reasoning for it, I'd love to hear from you.

 

[MatthewDiscipleofGod]

If you ask in a sincere way like you did here I'm sure you could contact Answers In Genesis and they would gladly give you more information. They have always responded to my questions. Once they even called me at home to talk.

Hmm...

I understand that you don't have an understanding of rubisco...Its not exactly headline news (the rubisco, I mean). But I have trouble accepting that enzymes involved in photosynthesis are flawed because of man's fall from grace.

I don't know. Perhaps this was the wrong forum to present this question. But if there are any biologists out there that understand the dilemma and could give me the creationist reasoning for it, I'd love to hear from you.

 

[mark kennedy]

This is a question for a biologist (or someone with a good understanding of biology) who is also a creationist. But, so that everyone can get the jist of the argument, I will do my best to explain everything.
Starting with some background:

I think you should know that this isn't a debate forum. That said your question seems purely academic so lets see what you have.

Photosynthesis is the process by which plants, and some animals, make food in the form of glucose typically from sunlight, CO2, and water. Photosynthesis has two main parts:

1) Light reactions: light energy is used to split H2O into H+ (protons) and O2, and to use those protons to make energy (in the form of ATP and NADPH).

I'm a little sketchy here, ATP is the fuel and the NADPH is kind of like a get 2 for 1 fuel if memory serves.

This energy is then used to power the second part of photosynthesis,

2) The Calvin Cycle: Basically constructs sugar from CO2 in a number of steps, which I will not cover.

The first part of the Calvin Cycle is Carbon Fixation, where the CO2 is attached to RuBP, a five-carbon sugar, by an enzyme called Ribulose-Biphosphate Carboxylase, or Rubisco.

Rubisco is a 5 carbon suger that CO2 attaches itself to at the outset of the Calvin cycle. Feel free to jump in if I'm missing something or getting something wrong.

CO2 attaches to the active site (a part of an enzyme) and is then attached to RuBP. However, O2 is also a good fit for the active site of Rubisco. In fact, O2 is a better fit than CO2, and therefore is a competitive inhibitor; that is, Rubisco will accept O2 before CO2.
When O2 gets to rubisco first, bad things happen for the plant. Instead of making a 6-carbon sugar as it should, the mistaken rubisco will actually cause the 5-carbon sugar to split into a 3- and 2-carbon sugar. The 2-carbon sugar is useless, and is exported from the chloroplast. This process of mistaken substrate is called photorespiration, and is bad for plants because it depletes its stores of starch.

But why does rubisco accept the oxygen, when that leads to disaster for the plant? Well, according to modern theory, it is evolutionary baggage. When rubisco first came around about 1.5 Billion years ago, there wasn't much oxygen in the atmosphere. Therefore, it didn't really matter whether or not rubisco accepted O2 at all, much less over CO2.

This all leads to my question:

What is the creationist reason for rubisco's flaw?

-Joe

*EDIT*
For clarification, rubisco's flaw is that it has a higher affinity for O2 than CO2, thus causing the problem of photorespiration.

I'm not following the problem but I am finding some pretty good literature on the subject:

Would you care to elabortate on what the actual problem here because this sounds like a suboptimal design arguement.

 

[joeferrari15]

That said your question seems purely academic so lets see what you have.

Correct. I'm glad you see it as such.

I'm a little sketchy here, ATP is the fuel and the NADPH is kind of like a get 2 for 1 fuel if memory serves.

More or less, yes.

Rubisco is a 5 carbon suger that CO2 attaches itself to at the outset of the Calvin cycle.

Not quite. Rubisco is the ENZYME that attaches CO2 to RuBP, which is a 5-carbon sugar, at the outset of the Calvin Cycle.

Okay, as for the problem....

Stomata (the openings in plants that allow for CO2 to come into the plant for photosynthesis) are also the main sites of transpiration (the evaporative loss of water from leaves). In order to combat this, plants in hot, dry areas close their stomata, thus drastically reducing the amount of water lost.
However, the closing of the stomata not only keeps water vapor from leaving the leaf, but also prevents oxygen (a product of photosynthesis) from leaving as well. As CO2 is used up in photosynthesis and O2 is produced, it follows that there will soon be more O2 in the leaf than CO2. Now, the concentration difference between O2 and CO2 wouldn't matter at all (other than that the plant would run out of CO2 with which to perform photosynthesis) if rubisco didn't have this flaw that it has a higher affinity for oxygen than CO2. Obviously, since there are more O2 molecules in the leaf than CO2, rubisco will begin to accept O2, thus causing photorespiration.

 

[laptoppop]

Indeed - it absolutely sounds like a sub-optimum design arguement.

I don't have knowledge about this in particular, but one thing strikes me offhand. The efficiency of current plants is a key part of the *overall* ecosystem. If you did not have this "flaw" -- wouldn't that make plants MORE efficient? If they were, wouldn't that cause a different CO2/O2 balance in the atmosphere? This would have profound impact on the rest of the ecosystem, including other plants and the animals and man.

Its also possible that there is a more direct benefit for other parts of the system, but I don't know enough about this subject to comment.

In other words, constraints and tradeoffs are a common part of design. Creation is designed as an overall system, not just as various parts. The parts can be fantastically complex and wonderful to look at seperately, but they make the most sense in context of the overall creation.

 

[mark kennedy]

Correct. I'm glad you see it as such.

I like little puzzles like this, I found a really neat web page when I looked this up on Google images. In fact I found several.

More or less, yes.

You just happen to hit on something I retained.

Not quite. Rubisco is the ENZYME that attaches CO2 to RuBP, which is a 5-carbon sugar, at the outset of the Calvin Cycle.

I think I'm with you, lets see where you go with this.

Okay, as for the problem....

Stomata (the openings in plants that allow for CO2 to come into the plant for photosynthesis) are also the main sites of transpiration (the evaporative loss of water from leaves). In order to combat this, plants in hot, dry areas close their stomata, thus drastically reducing the amount of water lost.

The Stomata sound like pores in our skin, they respirate, prespire...that sort of thing. What this made me thing about is the canopy theory, which honestly hasn't even been developed enough to make a good theory. At any rate the idea behind it is that water hung above the earth creating a greenhouse effect, a mist the watered everthing instead of raining and a protection from intensive UVRs from the sun.

It's a little far fetched but I would if that might have something to do with it.

However, the closing of the stomata not only keeps water vapor from leaving the leaf, but also prevents oxygen (a product of photosynthesis) from leaving as well. As CO2 is used up in photosynthesis and O2 is produced, it follows that there will soon be more O2 in the leaf than CO2. Now, the concentration difference between O2 and CO2 wouldn't matter at all (other than that the plant would run out of CO2 with which to perform photosynthesis) if rubisco didn't have this flaw that it has a higher affinity for oxygen than CO2. Obviously, since there are more O2 molecules in the leaf than CO2, rubisco will begin to accept O2, thus causing photorespiration.

It sounds to me like the plants are closing up their respiration vents so they can't dump as much oxegen as they need to. There is also an accumulation of water if I'm getting this at all which is componding it's affinity for oxegen.

I have no idea if that begins to address the problem but that's all I can think of at this point.

 

[mark kennedy]

Indeed - it absolutely sounds like a sub-optimum design arguement.

I'm wondering if this might be some baggage from the post flood environment. Maybe the problem isn't the plant, maybe the plant was designed for a different environment then it currently has to live in.

 

[laptoppop]

I'm wondering if this might be some baggage from the post flood environment. Maybe the problem isn't the plant, maybe the plant was designed for a different environment then it currently has to live in.

Very well could be. Of course, the Designer knew about the flood in advance, so He created a system which could function adequately in either environment.

I do think that understanding the presence of a Designer causes us to look at His Design differently than assuming that each piece is seperate. He has given us a complete system -- and in looking at it, our question can be "Why did He do it this way?" as opposed to just "How does this work". Being able to assume design changes our understanding of the purposefulness of the creation. Of course, the creation is fallen - so we have to account for that as well.

 

[Mallon]

Here's an interesting question that I would be interested in hearing an answer to from you guys:

If God doesn't consider plants to be alive (since there was plant "death" before the Fall), why would He punish them post-Fall by causing an inefficiency in the rubisco enzyme?

 

[joeferrari15]

It sounds to me like the plants are closing up their respiration vents so they can't dump as much oxegen as they need to. There is also an accumulation of water if I'm getting this at all which is componding it's affinity for oxegen.

Right. Since the pores are closed, oxygen can't escape. The oxygen accumulates, and very quickly is at a higher concentration than carbon dioxide and rubisco, not being able to tell the difference, starts using oxygen and photorespiring.

 

[laptoppop]

Here's an interesting question that I would be interested in hearing an answer to from you guys:

If God doesn't consider plants to be alive (since there was plant "death" before the Fall), why would He punish them post-Fall by causing an inefficiency in the rubisco enzyme?

I guess I don't see it as a "punishment" but rather as a reasonable design choice for a particular part of the system.

 

[mark kennedy]

Right. Since the pores are closed, oxygen can't escape. The oxygen accumulates, and very quickly is at a higher concentration than carbon dioxide and rubisco, not being able to tell the difference, starts using oxygen and photorespiring.

Understand this is just idle speculation, it could just be a consequence of the flood. Global warming is real, we are now realizing that the earth is getting hotter. Maybe it started getting hotter immediatly following the rains of the flood that removed the protective canopy and filled our oceans. The earth gets hotter, the pores close up more and they don't respirate they way they were originally designed to.

 

[laptoppop]

As a bit of a skeptic, I'm not convinced that global warming is the problem that it is portrayed to be. Don't get me wrong, I strongly believe in us being good stewards of the earth, I just haven't come to a conclusion - there's so much politicizing and sloppy data around this issue. Check out http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/05/nosplit/nwarm05.xml

In any case, I'm totally convinced the Designer knew all of history when He made the design - and created a appropriate design.