Dihydrogen oxide is one of the most lethal cellular toxins. It kills cells by causing them to swell uncontrollably and then burst, or in some cases to shrivel up like a crumpled piece of paper. However most all cells on earth have been able to resist this toxin by using a membrane protein to prevent its deadly actions. But even more interesting dihydrogen oxide or water is required for life and the aquaporin channel helps maintain a non-lethal concentration of this precious but deadly fluid.
Aquaporin is a fascinating integral membrane protein. It is able to "filter" water into the cell by keeping other polar or charged molecules around the same size as water out of the pore. Plant, animal and bacterial cells have aquaporin channels.
Questions:
1 How does aquaporin operate as a selectivity filter? What would happen to cellular metabolism if it did not operate as a selectivity filter?
2 The complexity and requirement of aquaporin for cellular life appears to be a problem for the evolution of the first cells. Or is it? Some plants cells can take in water without aquaporin. Could this represent a more ancient water controlling mechanism? Check it out and comment on what you have learned.
The aquaporin protein is a very specific protein that must be fine-tuned to only allow water molecules across the membrane while keeping the concentration of other ions and compounds the same. The protein is able to only allow water to pass being a very small size forcing water molecules to follow through single file. This line of water molecules remains intact by hydrogen bonds preventing other molecules from entering. The aquaporins prevent other small ions from passing through by precise electrostatic fields. Both of these concepts allow the aquaporin to work efficiently while not disrupting the balance of ions inside and outside the cell.
ReplyDeleteThis doesn’t appear to be a problem for evolutionists or an argument against. Water can cross some membranes without this channel which would allow water stability. Also, it seems that this protein would be able to be fine tuned throughout time since if some ions got through it wouldn’t kill the cell, it would just require the other mechanisms that control the gradient for these ions to work harder. Eventually the aquaporin would be able to completely exclude other ions and compounds from entering. There are many arguments for the complexity for the cell and against evolution and although this could be used as an argument for intelligent design, it seems that there are far better arguments for proving that evolution couldn’t happen through slow modifications.
Interesting points Nathan. Anyone agree or disagree with Nathan's analysis.
ReplyDeleteDr Francis
Why wouldn't the function and complexity of the aquaporin be a "good" argument for intelligent design?! What makes a "good" or "bad" argument when standing up for the intricate design of creation? It is the small, but multifaceted things of life that point back to the maker. Cells represent the very existence of physical life. For cells to function, DNA and proteins must work together to form a barrier to prevent unwanted reactions with chemicals in the environment. Information in the DNA constructs the cell membrane so that it selects substances useful to the cell and protects it from those that are harmful. All three factors- DNA information, protein catalysts (enzymes), and a protective environment is necessary for life to exist as cells. From this observation it is clear that the complex system of life demands an author. Information is a product of intelligence, signifying that the cell came from an intelligent source (the creator).
ReplyDeleteI agree with Nathan's analysis of the first question. The Aquaporin protein must have a very narrow channel. For it to be able to prevent most ions from passing through but allow water, it couldn't be much more than 4 Angstroms wide (This is the width of a water molecule). This type of precession displays a huge amount of complexity. Even if plant cells have other means of allowing water to pass through, how would a cell transition into a Aquaporin dependent cell? This doesn't sound like one of those "slight modification" that Darwin said his Theory depended on. I would disagree with Nathan's answer to the second question. To me, this does appear to be a problem for an evolutionary model.
ReplyDeleteNathan had a good point about the aquaporin being able to be skightly flawed and still adequately protect the cell, however I do think that there could still be an arguement for creation in there. If cells lack the aquaporin then the only way for water to enter would be endocytosis, which allows for a host of other things to enter the cell, or allowing water to squeeze in through the plasma membrane, which can happen but it is extremely slow. Aquaporin allows water to move through the membrane much faster, therefore allowing water to move through the cell faster. Without aquaporin cells would not be able to take in or release water fast enough to survive changing conditions in their envrionment without risking taking in water contaminated by ions or other contaminents.
ReplyDeleteMy guess as to why some plant cells that are able to survive without aquaporin is that their cell wall prevents them from bursting or shrinking too much when the ion gradient gets thrown off by the intake of ion contaminated water. If the plants live in freshwater envrionments then the need for an ion-filtering membrane protein may be less significant. Just a theory...
1. In a general sense, aquaporin is a protein which controls the flow of water into and out of the cell, which happens in a very specific and controlled way. The main purpose of aquaporin is to change the orientation of the water molecules so that it only lets in the right type of water molecules (those without protons). It is completely impermeable to ions, and this helps the membrane keep it's characteristics. However, protons could make it through the protein when attached to water molecules, so the aquaporin forces the water molecules to line up single file, and makes them out of position to be able to give their extra proton away. Aquaporin uses amino acids as the filter, also known as ar/R (aromatic/arginine) filter. If this filter was not there, it would allow ions and other molecules into the cell that could damage or even kill the cell because they are not meant to be there.
ReplyDelete2. I was just thinking about what the speaker in chapel said on Friday. Even Darwin himself said that if anything could be found that was not evolving in small steps it would be an argument against his evolutionary hypothesis. If we take this part of how the cell works, and try to remove one or more parts from it, would the process still work? What if the one of the parts were not perfected, would the process still work then while keeping the cell alive?
I think that for aquaporin, it seems too complex for it to have evolved. I don't think there is any way for the protein to be randomly folded in such a complex way without the intelligence of a creator. I also do not believe that the aquaporin would work if one of the parts were not there, hence it's irreducible complexity. I'm not 100% sure of this yet (need more research).
Here is a link to a picture of what aquaporin looks like...
http://en.wikipedia.org/wiki/File:AQP1.png
Marcy, I like your point about how even the smallest parts of life, like a cell point to the intelligence of a creator!
1: Like Nathan said, the aquaporin must be so small a channel that it only lets in water molecules though a single file system. If the channel is that small and in fact does only allow one molecule at a time pass though to the inside of a cell, then while water is coming in, that must not allow any other ions to be able come in. Either that or there is a receptor on the outside of the aquaporin which molecules/ions can come in. The cellular metabolism would most likely slow down because it wouldn’t have a filter system in order to get rid of the impurities of what comes in the cell. The cell would probably have to self destruct itself because it would no longer be a good environment for the cell to be in if the inside of the cell didn’t have a filter.
ReplyDelete2: From what I can find, the narrow pore of the aquaporin acts to weaken the hydrogen bonds between the water molecules, which allows the water to interact with the positively charged arginine, which also acts as a proton filter in the pore. It seems logical to me that some plants can function without aquaporin because extremely water based plants need the water and the structure of the plant can keep under control the amount of water that is being taken in without the aid of an aquaporin. One plant that comes to mind is celery. That is a water based plant that has a hard and tall structure which has visible channels where water travels through the chute of the plant.
1. The aquaporin protein uses the charge of water to allow it to enter the cell. The channel protein has a magnetic field that orients the oxygen facing the inside of the cell, then it switches midway through and the hydrogens face the inside. The charge of the protein also breaks the hydrogen bonds between water molecules, which allows them to pass through the protein one at a time. The small size of the protein pore and the charge is what makes the protein selectively permeable; only small molecules with the right electric charge can pass through the membrane protein. The protein also allows protons to pass through, which are a central part of cellular metabolism, in that they cause the gradient required in the synthesis of ATP.
ReplyDelete2. Water can be transferred to cells in plants without the aquaporin protein through the plasmodesmata connecting cells, but this doesn’t solve the problem of how water got into the cells initially. Before the discovery of the aquaporin protein, it was assumed the water permeating the membrane through pores was enough to sustain the plant, but the discovery shows otherwise. Scientists are still unsure of all the capabilities and restrictions of the aquaporin protein.
1) According to our textbook on page 146, the membrane protein Aquaporin is selective (it only allows water molecules to pass through, while excluding protons) because of a certain narrow point in the protein channel. At this point, positive charges on the protein attract and reorient water molecules so that the hydrogen bonds connecting them to other water molecules are severed. The reoriented water molecules flow on through single file, at the rate of one million individual molecules per second. Since the water molecules are not joined, there is no “bridge” for protons, which normally travel along connected water molecules, to enter the cell.
ReplyDeleteIf the Aquaporin wasn’t water-specific then there would be an disruption in the “proton-motive force.” The book defines this as “An electrochemical gradient that is built up across energy-transducing membranes (inner mitochondrial membrane, thylakoid membrane, bacterial plasma membrane) following the translocation of protons during electron transport. The energy of the gradient, which is comprised of both a pH gradient and a voltage and is measured in volts, is utilized in the formation of ATP.” Basically, if there is an undesired imbalance of protons, the formation of ATP is impossible. ATP supplies the energy for cell metabolism, which is “the chemical processes that occur within a living organism in order to maintain life,” according to the New Oxford American Dictionary. To summarize, if the Aquaporin was not selective and instead allowed protons to flow freely into the cell, then the proton-motive force would be incorrectly unbalanced, ATP wouldn’t be formed, cell metabolism wouldn’t take place, and the cell would die.
2) Plants take in water by osmosis, because the inside of their cells is hypertonic to their environment. However, the inflow of water in this way is slower than the flow through Aquaporin. But, since Aquaporin is a problem for evolution, osmosis may be the only option left for how early cells took in water. And it is feasible. If the cytoplasm of early cells was hypertonic, and the cell didn’t require rapid inflow and outflow of water, then it is plausible that the method of water transport that is utilized by plants could also have been utilized by these early cells. However, like plants do now, early cells would have needed to possess a strong cell wall to prevent the cell from bursting as a result of the increased pressure from the higher internal volume of water.
ReplyDelete1. aquaporin operates as a selective filter because it is specific for water molecules only. They only selectively conduct water molecules across the membrane. It is a protein with a specific function. They allow protons to flow through which is vital in the the membrane's electrochemical potential. If it did not act as a selective filter, this would affect the cellular metabolism in that if there is an imbalance in the flow of protons in the cell, then there is an imbalance in energy. The selective process of allowing protons are needed for the formation of ATP which supplies energy to the cell. So if that selective force is taken out then there would be no ATP.
ReplyDelete2.Aquaporin, to me is so complex to even consider it to have just evolved. Since it is so complex, it poses a problem for evolutionists and i agree with Sam that osmosis may be the only way early cells took in water. The reason some plant cells dont have aquaporin is that maybe there cell walls are strong enough to control the cells in the plant from bursting.
Aquaporin is able to 'filter' in water while at the same time keeping all other charged particles out of the pore. Water molecules are forced, by the protein's elextrostatic forces, to flip at the center of the channel. This breaks the hydrogen bonds on the molecule which is necessary for proton translocation, thus blocking the charge to get into the pore. If it did not operate as a selectivity filter, there would be imbalance in the cell. This would seem to be a problem for evolutionists. Something so complex and 'selective' could not have merely evolved. There seems to be some intellgent design in the structure of such a small, yet intricate cell.
ReplyDeleteAquaporin serves as the water channels which only allow the water molecules to pass through the single file. Even though there are molecules smaller than water could not pass through aquaporin channel because of their differences in electrochemical properties. When it does not operate as selective filter, then i will cause the cell to swell. There is a problem for evolutionists, because through endosymbiosis they believe prokaryotic cells turn into eukaryotic cell, and therefore why does some plants cells can take in water without aquaporin. This has proven that even the cell, the basic unit of life, is discontinuity, and this is definately not evolution.
ReplyDelete1. Water molecules traverse through the pore of the channel in single file. Aquaporins selectively conduct water molecules in and out of the cell, while preventing the passage of ions and other solutes. I agree with what Eric said in that the aquaporin protein uses the charge of water to allow it to enter the cell. So there must be a way that the aquaporin with the carboxyl oxygens from the amino acid facing the inside act as a barrier from anything except water. The water moves through the aquaporin in a very organized way. Small pore sizes only allows small molecules like water to pass through.
ReplyDeleteIf it did not operate as a selectivity filter, the cell would burst so the cellular metabolism would not work and it could not maintain its structure anymore or perform operations to grow or live anymore. The metabolism determines which substances the cell would find poisonous and it finds water to be toxic. The strictly opposite orientations of the water molecules maintain a rapid flow while keeping them from conducting protons…If these channels were leaky for ions, the electrical potentials of the cell walls would be abolished, leading to a complete breakdown of the cell metabolism.
2. Aquaporin is required for cellular life in most cases. If you took it away, most cells would not function so I think that this is a good argument against evolution. hen plant roots are exposed to mercuric chloride, which is known to inhibit aquaporins, the flow of water is greatly reduced while the flow of ions is not, supporting the view that there exists a mechanism for water transport independent of the transport of ions: aquaporins. To me this just shows even more complexity because there is another way that water can go into a cell and not destroy it where usually without aquaporins the cell would be destroyed. This shows more complexity in my opinion and design instead of random evolving.
So...basically, looking at number 2 and reading other responses, I would say that because of how complex this system is, it would be more difficult to explain something evolutionary than to just say that God created this aquaporin for the regulation of water molecules...no strings attached. I do not think that aquaporin is the only way of homeostasis; I'm sure God had a much bigger more complicated explanation that we possibly haven't discovered yet or ever will. Isn't he awesome?? :) The beauty of science is discovering how great of a creator He really is! :D
ReplyDeleteAquaporin has narrowed channel that force the water molecules to line up in a single file. Ions will be filter out because they have larger size than water and so only water can get through this small channel into the cell. This complexity has proven evolution is wrong, how many billion of years do we need to wait until every single cell to turn out perfectly to form an organism.
ReplyDelete1. The aquaporin channel is large enough to let in H20 molecules one at a time through. The channel is mostly made up of negatively charged amino residues, but near the tightest section of the channel, there are 2 amino residues with a positive charge, this changes the orientation of the H20 molecule, disrupting the normal flow of protons that attach to H20 molecules. Because of this specific change in orientation, it acts as a selectively permeable channel.
ReplyDeleteIf the aquaporin channel did not filter out protons and other molecules, ions, and atoms, the cell would not be able to regulate the flow of molecules that enter into the cytoplasm. This would destroy the cell because it would not be able to maintain homeostasis. The cell would either lyse or completely shrivel up due to osmosis and diffusion.
2. After looking through research journals and other websites, I have found that scientists do think there are other ways besides through aquaporin channels, but they have not yet gotten any diffinitive results. The only other way that I can think of is through membrane diffusion, but H20 molecules are rather large and would take a long time to diffuse across the membrane without any help. Maybe because plants are so diverse (aquatic plants vs desert plants) the way they take in water is very different as well
1.Aquaporin channels are very specific to water, very little except water can pass through it. The size of the aquaporin channel is specific to the size of the water molecule a bigger molecule would not be able to pass through and a smaller uncharged solute could pass through but this would not prove dangerous to the cell. Some aquaporin channels allow uncharged solutes such as glycerol, CO2, ammonia, and urea in anyway, so these would not prove harmful. And aquaporin channels are completely impermeable to charged species so that rules out many different molecules. If it was not selective any ion could get into the cell. Calcium for example, and it would signal cell reactions that were not to occur at that moment. Cell toxins could be let in as well which would prove disastrous to the cell.
ReplyDelete2.It could prove to be a problem for evolutionists. Plant cells and mammalian cells are completely different structures. Mammalian cells could need a faster influx of water than plant cells do. Plant cells take in water through osmosis but it is a very slow process. If mammalian cells have to have a fast influx of water, how could they have survived without the aquaporin channel? They could have possibly survived with osmosis, but that may not have been enough water to sustain the cell.
1. Aquaporin uses the polar and nonpolar ends to pass the water through the cell membranes. Cellular metabolism would be thrown off it's course because other materials would exit the cell besides water, materials that are needed for the cell to continue to develop and grow.
ReplyDeleteAquaporin functions as a selectivity filter in several ways. First it utilizes different peptide sequences that control the shape of the channel. It can make them smaller or larger depending on what needs to pass through. In this way it can “selectively” allow only water to pass through the channel. It also utilizes charge to prevent the passage of certain ions and other solutes.
ReplyDeleteAs far as evolution goes, this would be a problem they would have to explain. Since we now know that water must go across channels in order to maintain a good level of water inside and outside of the cell than it doesn’t leave a lot of room for millions of years of evolutionary “trial and error” to create aquaporin channels along with all the other mechanism that would have need to suddenly evolve all at once. It is just one more building block to add to the case against evolution.
1.Aquaporin is specific to water both by being sized so that only water may enter, but also using the charge of the water. This prevents any charged particles, such as protons, from entering the cell. If the aquaporin were to misfunction, the flow of water in and out of the cell would be disrupted. It also would allow for charged particles, such as Ca2+ or other molecules which are essential to life, but cannot exist in too great a quantity into the cell. This could cause the cell to misfuntion and die.
ReplyDelete2.The aquaporin channel is extremely complex, meaning it would be difficult for it to evolve. While some do not have aquaporin, this does not mean that it evolved.
1 How does aquaporin operate as a selectivity filter? = aquaporins are proteins that control the flow of water into the cell they only allow water molecules to flow single file through this protein channel, the can constrict the flow of water into the cell so that the larger objects can't get through and cause damage in the cell.
ReplyDeleteWhat would happen to cellular metabolism if it did not operate as a selectivity filter?
if these are not operated correctly they could cause many human diseases ranging from misfolding of aqp2 creates water reabsorption problems in the kidneys diabetes, and some more.
2 The complexity and requirement of aquaporins for cellular life appears to be a problem for the evolution of the first cells. Or is it? Some plants cells can take in water without aquaporins. Could this represent a more ancient water controlling mechanism?
being that this channel is so precise in its job i doubt that this channels would evolve into anything more simple.
1)Aquaporin is specifically structured to let in water molecules in single file. The amino acids lining the channel break up the hydrogen spheres that are present in water and allow one molecule through at a time. This makes it impossible for anything else to enter the cell. Aquaporin channels make sure that the cell doesn't let in any foreign molecules by constantly being filled with water molecules, and at the same time makes sure that only just enough water is let in so that the cell doesn't succumb to osmotic pressure. Cell metabolism would halt if aquaporin didn't work correctly.
ReplyDelete2)one problem for evolution is it's direction. Things go from messy to controlled and organized. but for an aquaporin channel to work, it has to work precisely, or else the cell dies immediately. another problem is that evolutionists say that water is needed for life. but aquaporin would have had to develop very quickly in the first cell before it experienced lysis or crenation. i don't see how such a complex machine could just randomly appear so quickly....
1 How does aquaporin operate as a selectivity filter? What would happen to cellular metabolism if it did not operate as a selectivity filter?
ReplyDeletewithout the filter there would be major problems with the setup of the system, letting water molecules in one by one is a big job in its self.
2 The complexity and requirement of aquaporin for cellular life appears to be a problem for the evolution of the first cells. Or is it? Some plants cells can take in water without aquaporin. Could this represent a more ancient water controlling mechanism? Check it out and comment on what you have learned. the channels dont let anything that is foreign in.
1. The aquaporin's selectivity filter is a clump of amin acids that bind to H2O molecules that try to go through the pore. This is the mechanism that aquaporin uses to bind H2O molecules selectively and hinder others from entering. Also, this narrow power acts in a way to weaken the bonds between the H2O molecules. This allows water to interact with the positively charged arginine. This also allows it to function as a proton filter for the pore.
ReplyDeleteThe function of aquaporins is to increase the osmotic permeability of membranes above that of the bilayer. If aquaporins were not present, “the net water movement at a rate suitable for fulfilling certain cellular or transcellular functions would not be sustained” (Hill).
ReplyDeleteAquaporins form tetramers in the cell membrane and facilitate the transport of water and also small solutes across the membrane. However, the water pores are impermeable to charged species. Water flow through aquaporins is in the direction of osmotic pressure across the membrane. It is a passive process.
Usually the channels of the aquaporins are always open; however in plants, the aquaporins have acquired a molecular mechanism which causes the channel to close in harsh conditions. For substances that are charged, and wanting to cross the membrane, one way that the substance can cross the membrane is if an electrical potential difference is present across the plasma membrane. The electrical potential will drive the substance across the membrane.
The function of aquaporins is to increase the osmotic permeability of membranes above that of the bilayer. If aquaporins were not present, “the net water movement at a rate suitable for fulfilling certain cellular or transcellular functions would not be sustained” (Hill).
Aquaporins form tetramers in the cell membrane and facilitate the transport of water and also small solutes across the membrane. However, the water pores are impermeable to charged species. Water flow through aquaporins is in the direction of osmotic pressure across the membrane. It is a passive process.
Usually the channels of the aquaporins are always open; however in plants, the aquaporins have acquired a molecular mechanism which causes the channel to close in harsh conditions. For substances that are charged, and wanting to cross the membrane, one way that the substance can cross the membrane is if an electrical potential difference is present across the plasma membrane. The electrical potential will drive the substance across the membrane.
http://bioweb.usu.edu/taste/papers/aqp%20review%20JMbBiol.pdf
1. Aquaporin selectively allows water to move through it as it is the same width as a water molecule and the walls of the channel form hydrogen bonds with the oxygen to regulate the movement and prevent other ions from diffusing through. If it did not work this way, incorrect amounts of water would enter the cell and possibly ions that were not needed or needed in lesser amounts as provided by their appropriate channels and this would likely result in a reduction in the cell's functionability and eventually premature cell death.
ReplyDelete2. The existence of aquaporin-independent cells does not prove that aquaporin cells evolved from these. It is likely that cells that use aquaporin have a greater abundance of water around them and therefore need less than is available while cells that use phagocytosis may have a scarcer water resources and thus need to take as much water as possible. The whole idea of evolution in any sense is so unlikely as it proposes the chance development of highly irreducibly complex systems.
2). One of the big problems that aquaporins might give to evolutionists is that early cell life, according to many of their theories, began in watery environments. Because water is so toxic in high concentrations, cell would need to have someway to control water intake. Otherwise, dihydrogen oxide would burst the cells. It is also a problem for evolutionists because there seems to be no earlier or more simple form of this protein. Also, plants are able to intake water without these aquaporins. Are evolutionists going to think that all life originated from plants? This cannot be. Aquaporins, just like many other biological machines, is very complicated and is able to distinguish between water and other small ions and particles, allowing only water in. If it let anything else inside of the cell, this could cause other problems, causing the cell to have a more positive charge for example (by letting in protons). However, this could be used for evolutionists because most all organisms have been found to have this protein. This shows a sort of commonality. Evolutionist could also turn this around and say that because cells started off in a watery environment, aquaporins were made. Aquaporins could be used prove their point...kind of.
ReplyDeleteOk I found a website called aquaporins.org…I just thought it was too great not to quote…
ReplyDelete“Aquaporins form tetramers in the cell membrane, and facilitate the transport of water and, in some cases, other small uncharged solutes, such as glycerol, CO2, ammonia and urea across the membrane depending on the size of the pore. The different aquaporins contain differences in their peptide sequence which allows for the size of the pore in the protein to differ between aquaporins. The resultant size of the pore directly affects what molecules are able to pass through the pore, with small pore sizes only allowing small molecules like water to pass through the pore. However, the water pores are completely impermeable to charged species, such as protons, a property critical for the conservation of membrane's electrochemical potential.”
http://www.aquaporins.org/aquaporins/structure.htm
as far as what would happen to the cell without this selectivity filter, I think you’ve already touched on it. The cells would either have water flowing into them freely and thus swell and burst, or the cells would not get enough water to sustain them, and they would shrivel up and die. Both scenarios would be detrimental…
Going back to Nathan’s original comment on whether or not the plant cells that lack aquaporin could be a legitimate argument for or against evolution, I agree with Nathan on it. (sorry for the terrible sentence structure there) ANYway, plant cells have cell walls, which may help protect them from the intake of too much water which would cause animal cells to burst. And because of their vacuoles, maybe they can release water in a more controlled manner without the use of aquaporins to regulate it. Not to mention, the fact that prokaryotic cells still use aquaporins to regulate water transport, one can’t argue that there was an evolution of simpler to complex in this case, because the more complex plant cells DON’T have them, where the less complex bacterial cells do.
Aquaporin channels have a positive charge that pulls the oxygen right though in a single file forcing the H ions to stay out. The channel prevents other unwanted ions from passing through, without it there would be a cellular imbalance of particles. Aquaporin alone is so complicated; I don’t see how evolution could explain it. Evolution is an explanation for simplicity that “evolves” to complexity, but where is the simplicity here. It would have either had to develop quickly or be there from the get go and this in the first single cell? Doubt it.
ReplyDelete“The ar/R (aromatic/arginine) selectivity filter is a cluster of amino acids that help bind to water molecules and exclude other molecules that may try to enter the pore. It is the mechanism by which the aquaporin is able to selectively bind water molecules (hence allowing them through) and prevent other molecules from entering.” (wiki)
ReplyDeleteApauporin channels are also size selective, only allowing molecules in a certain size range to enter. If it didn’t act as a selectivity filter, it would allow a flood of other molecules to enter the cell, slowing down the metabolism.
I couldn’t find anything on aquaporin free plant cells, but I’m guessing they have different channels that regulate water. Possibly the cells that don’t have aquaporin don’t have the same water needs as most, therefore have a less sophisticated water channel system.
1 The aquaporin takes in and rejects the toxins or part of the toxins it wants. It does this by moving the water in a very organized way. The way aquaporin works is that the water molecules transverse through the pore of a single channel in a single file. Cellular metabolism would be destroyed by the dihydrogen oxide bad toxins if it did not operate as a selectivity factor because the bad toxins and very harmful and will immediately kill the cell.
ReplyDelete2 This is definitely a problem for evolutionists because it is hard to imagine that their system is correct with all the complexity in such small things. They wouldn’t be able to prove any of the aquaporins origins since because of its complexity. I wouldn’t say that it’s an ancient mechanism because I don’t think there’s any way of proving that.
The aromatic/arginine selectivity filter is a cluster of amino acids that help bind to water molecules and exclude other molecules that may try to enter the pore. It is the mechanism by which the aquaporin is able to selectively bind water molecules, which is allows them through, and prevent other molecules from entering.
ReplyDeleteThe aquaporin channel works selectively by channeling the water molecules through a very narrow point in the channel in a single file line. At the narrow point in the protein, the positive charge in the protein attracts the water molecules and severs the hydrogen bond between them. This makes it so protons that could usually move through water cannot enter the cell. If the aquaporin channel were not selective, the cell could not regulate what entered in and would be destroyed.
ReplyDeleteThe aquaporin channel does create a problem for evolution because the first cells were supposed to have evolved in watery environments and in order for a lipid bilayer to get rid of the water it would need a way to control intake of water as well as output. I don't think that the plant form of taking in water is representative of the first cells because without a cell wall plant cells would burst and i don't believe that the first cells had cell walls.
1 How does aquaporin operate as a selectivity filter? What would happen to cellular metabolism if it did not operate as a selectivity filter?
ReplyDeleteaquaporin acts as a security guard. It checks what is going in the cell. filtering out what is good and what is harmful to the cell. amino acids are used to filter the water particles. it lines all the molecules up and checks every single one very quickly. without the selectivity, harmful particles could enter the cell, killing or damaging it, causing a mutation. this also forms ATP, without it there would be no ATP formation.
2 The complexity and requirement of aquaporin for cellular life appears to be a problem for the evolution of the first cells. Or is it? Some plants cells can take in water without aquaporin. Could this represent a more ancient water controlling mechanism? Check it out and comment on what you have learned.
this isn't necessarily "ancient water controlling" it is just different. Different cells require different techniques. There is variability in God's creation. it some cellular circumstances, aquaporin just would not work, therefore a different mechanism is used. most mammalian cells would perish without the aquaporin filter, how could they have continued to reproduce without it if they were dying?
After some research and through reading to some of my friends posts and because of my new "addiction" to coffee, I have come to the conclusion that aquaporin in a way acts like those coffee filters you put before making a new batch of "human fuel." It filters what comes in, so that the cell wouldn't have to mess with the unneeded "grounded coffee.
ReplyDeleteHowever there are some cells which seem not to need this coffee filters, some plants like their coffee with "pulp" I guess. God is unique with what he makes, having plants who rely on aquaporin with plants who never may have a use to it, just shows the diversity of he has created.
So the aquaporin channel acts as a selectivity filter. It filters stuff going in and out of the cell with proteins, more specifically amino acids. This will protect the cell from any harmful bacteria going inside the cell. One thing it does is that outside material will have to pass through a channel, and these channels have a charge that attracts the water molecules and orders them in a single file line so that they can be monitored more closely when passing through the cell membrane.
ReplyDelete