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Sunday, February 27, 2011

Cellular UPS and bad design

As I have mentioned in class, I think that bacteria and viruses appear to possess  features consistent with the idea that they are designed to deliver agents to cells.  For instance, their size is conducive to cell interaction and many possess elaborate motors , docking and delivery systems.  In fact, the bacterial flagellum which is often advertised as having one function, actually demonstrates many functions, i.e. it is a docking/binding agent as well as a motor, it also appears to be a receptor in some instances.  Thus the flagellum demonstrates co-option; it has more than one function,  an idea that many intelligent design theorists don’t like.  In addition some bacteria can control the actin polymerization inside cells inducing the cells to make “cellular arms” or pseudopods.  Thus they  induce the cell pseudopods to engulf them and they enter the cell in this manner.  Recently, researchers have used  bacteria to deliver a virus to a cell which induced profound genetic changes in the cell.  Viruses themselves possess several elaborate mechanisms for engaging cells and entering cells.  Viruses not only deliver genetic information to cells, but they can deliver proteins, they can control intracellular biochemistry and they can deliver membranes and membrane proteins.  Take for instance the flu virus.  It is an enveloped virus.  Technically when it leaves a cell it takes along some membrane from that cell.  Could it be that everytime you get a flu, you also get some proteins and membrane components from your friends?   What are the long term and short term implications of this?  But then again, viruses and bacteria can cause lots of problems.  If these creatures were designed as extracellular delivery organelles, is this the best design?.... because it appears that with a few "slight modifications" they can become agents of cellular destruction.

Questions:
1 Discuss the microbial extracellular organelle theory as described above.  What are its strengths and weaknesses as a theory?
2 If bacteria and viruses are designed delivery agents, why does our immune system try to eliminate them?  Or does it?

40 comments:

  1. 1. Because new proteins are being acquired that may be beneficial as it may lead to genetic diversity. It is also extremely complex as a mechanism: what are the chances of the proteins being delivered at the right time to the right organism, how would the organism know it needs new genetic material? The fact that no benefits have arisen from a virus thus far, it does not seem likely that the bacteria and viruses were meant to bring new DNA, and I can't think of any other profitable deliveries they could be making.

    2.I would say the immune system does try to eliminate bacteria and viruses. Natural Killer (NK) cells attack bacteria by releasing the proteins perforin and granzyme which cause apoptosis in the target cell. The immune system also uses ribonucleases against viruses.

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  2. 1. One of the strengths of the microbial extracellular organelle theory is that it does make sense in the fact that bacteria do deliver agents to cells. Because there is evidence that bacteria do have many other functions that are consistent with delivering agents to other cells such as its "elaborate motors, docking and delivering," this also increases the theory's strength. The only problem, is the question of why the bacteria would need to deliver more information, more deliveries to a cell that is already complete. In the endosymbiotic theory in which the bacteria invaded a cell and the bacteria became a mitochondria or in a cyanobacteria's case, a chloroplast, why does that not happen today? Cells have defensive mechanisms to destroy unfamiliar objects such as bacteria which make it really difficult for the bacteria to live within the cell

    2.I would agree with Hannah that our immune system does try to eliminate bacteria and viruses. As to the reason why, could it be because they are usually so much different from our normal cells and usually cause so much damage to our body systems that our immune system is programmed to try to destroy them on site?

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  3. Dr. Francis as you mention that viruses not only deliver genetic information to cells, but they can deliver proteins, control intracellular biochemistry and deliver membranes and membrane proteins. I think that the whole idea of virus is delivering agents to cell is the virus is trying to invade the cell for destruction in a sense that they deliver membrane as an undercover from the attatck of the immune system. Because the membrane contains the carbohydrate to help the cells to differentiate the outsiders, in oder for viruses to invade the cells, they should also cover themselves with the carbohydrates which is in the membrane. Here come to the question then why if bacteria and viruses are designed delivery agents, why does our immune system try to eliminate them? by refering back to the lecture that carbohydrates in the membrane determines human blood types. Therefore, once the viruses deliver the membrane which is from for example another person, then the different of blood type will alert the immune system to attack the viruses. On the other hand, if the viruses carry the membrane of the same bloodtype, then the immune system won't take the action to destroy the viruses. Sorry if these do not make sense, this is only my thought about the topic.

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  4. 1:The microbial extracellular organelle theory seems like it is a system in which bacteria and viruses can deliver genetic material, and proteins to the cell. However, viruses are infectious agents that have the ability to cause major damage to a cell. This could also lead to infections that are only dealt with through an immune response which eliminates the virus or if necessary, vaccines and anti viral drugs. The strengths of it are that it can enter the body and deliver things to the cells through a (what I like to think of it as) disguise. It’s almost like the virus enters and gets as far as it does because it’s pretending to be something that it’s not. This is definitely a strength for the virus but it is destroyed easily by the immune system response or vaccines and anti viral drugs as mentioned earlier. Both viruses and bacteria cause a lot of problems inside the cells which is why this is a weak point for the theory that viruses and bacteria actually exist to do the human body more things good than bad. It doesn’t logically make sense. Why would God create something that’s main purpose is to deliver things to the cell when it actually hinders it and does more harm than it does good? The only reason that I can figure as to why the virus and bacteria both do some good things for the cell is because it’s a cover for them to be able to have access to the cell. Once they have access they start their destruction.
    2:The whole point of having an immune system protect against disease by identifying and killing pathogens and tumor cells. The immune system is perfectly capable of detecting the healthy cells and the infected cells by a presence of viruses and bacteria. The immune system basically gets rid of viruses by the T lymphocytes and bacteria by the plasma cells. The immune system wouldn’t be programmed/designed to kill the viruses and bacteria unless they weren’t good for the cells and the body as a whole.

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  5. 1. If we are thinking in a creationist perspective, everything was created with a beneficial purpose but after the fall not everything was beneficial. Could it be that God created bacteria and virus to be delivery agents but after the fall bad design entered in? I think that is very possible. In regards to strengths and weaknesses they seem to be very able to be cell messengers. Everything seems to fit perfectly for this theory to make sense. The problem is there does not seem to be any good reason for this. So far we are only able to see harmful consequences. I just don’t think, right now, they can be good for cell messaging.
    2. We’ve learned that some bacteria are good, and our immune system does not try to destroy these forms of bacteria. Obviously it knows the difference between what is harmful to our bodies and what is beneficial. And I just do not think that bacteria and viruses are designed to be delivery agents, the reason they have those characteristics is so that they can easier enter a cell. It’s part of their design so they can be better destroyers of the cell. The immune system is aware of the destructive forces so it works as hard as possible to eliminate them.

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  6. 1 Discuss the microbial extracellular organelle theory as described above. What are its strengths and weaknesses as a theory?

    Microbial extracellular organelle theory has many strengths. Considering what we have learned about the plasma membrane’s signaling system, it would make sense that there are many external organisms which stimulate various signals in a cell. In addition, there are specific mechanisms which are designed to access cells. This was discussed in the “Cellular UPS and bad design” article.
    Even the “Weaknesses” show a purpose. For example, the fact that slight modifications can produce deadly consequences shows me that at the fall, God could have slightly modified some of these microbial extracellular organelles like viruses and bacterium.

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  7. 2 If bacteria and viruses are designed delivery agents, why does our immune system try to eliminate them? Or does it?

    Our immune system defiantly utilizes natural killer cells to destroy foreign organisms. But, our intestines are lined with countless bacterium that live symbiotically with us. Why doesn’t our natural killer cells attack and destroy these bacterium? Maybe they have specific carbohydrates in their glycoproteins which natural killer cells recognize as a part of the body. Maybe some of these carbohydrates are found in the delivery bacterium and viruses?

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  8. 1. What you said Francis about intelligent design theorists confused me. Why can a flagellum not have multiple functions? What are their ideas on that? I do agree with the fact that bacteria and viruses can have multiple functions as a delivery agent. Were they made for that sole purpose? I think not. Clearly many of them are infectious, so I'm thinkin' that God may have created the ability to engulf and deliver, but not harm in the pre-fall.

    2. Because not all bacteria is pathogenic, I would say that our immune system doesn't try to eliminate all of them. This is also true for viruses in humans. Not all viruses are pathogenic for humans, some will only infect plants and animals. (http://wiki.answers.com/Q/Are_all_biological_viruses_pathogenic),

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  9. Dear Soul Sistas thanks for asking for a clarification. Critics of those who claim that the flagellum is designed suggest that because the flagellum might have other functions that that is evidence that the flagellum once served another purpose..and maybe it had another function with fewer parts than it has now....that would show that the flagellum is not irreducibly complex.

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  10. 1. This theory makes sense in the sense that some of the organelles have a little bit of their own DNA. It is also helpful that the viruses and bacteria could carry needed things, like proteins and membrane parts, etc into the cell. The only drawback I can see for this theory at this point is that once the virus/bacteria is in the cell, it can destroy the cell by infecting it. Hey, I wonder if this is how our cells make antibodies??? Our cells can come in contact with the virus/bacteria which would be attacked by the immune system and even if the cell dies, the immune system would have antibodies to repel attack in the future. (I don't know, just a thought!)

    2. If our immune system does try to eliminate the viruses and bacteria (and I believe that most if not all of the time it does), I think the reason why they are attacked by the immune system is because it is foreign to the cell. I remember talking about this in class (when Dr. Francis was covering himself in scantrons, aka carbohydrates :) that cells, specifically blood cells want to look like they blend in to their surroundings so the immune system will not destroy them. So, since the viruses and bacteria are not a part of the cell, they would be attacked by the cell. I do not think that viruses and bacteria were necessarily DESIGNED as delivery agents, but COULD have this purpose.

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  11. 1. As for questions 1, I agree with K. Preheim’s view on the microbial extracellular organelle theory. As creationists we must believe that everything was created with a beneficial purpose, but with the fall it was perverted and distorted. Why could bacteria not be created with the purpose of being helpful and beneficial delivery agents? If God could make bacteria, would it be so hard as to make it constructive? Just because we are only seeing the harmful consequences, does not limit the good that bacteria could do, is doing, or will do. Just like the appendix with researchers not knowing its whole implication and purpose for the body, does not negate it as harmful or useless. We then should view bacteria as such.
    2. As for questions 2, I agree with the facts put forward by Micayla Franklin. Bacteria is “foreign” to our bodies, thus they are attacked by the body. Human bodies have a number of strategies to fight infections or prevent them. The whole of our infection fighting apparatus is called the “immune system.” The human body’s immune system doesn’t just include white blood cells, which attempt to catch and destroy germs, but a variety of mechanisms that stop germs from creating infection. But I do have a question for you Dr. Francis….because bacteria desires to blend in and participate within the environment do you think there is a purpose for this? Maybe bacteria are not really “foreign.” Meaning that they did have a position and belong within this system. Just like how organisms are created to live with each and provide for one another, could we not say that bacteria are actually quite “familiar?” It reminds me of people with autoimmune diseases, like Lupus and HIV that trick immune cells into believing other cells of the body are “foreign”, but in actuality they are not. This causes the body to attack these useful and functional cells which causes cell death and organ dysfunction. Than when our body attacks bacteria, is it not attacking itself?

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  12. Yes I agree Marcy, I think Bacteria possess features which allow them to persist in places they were meant to be...interesting!

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  13. I can't help but think of creation and the fall in this discussion. I've always tended to think that bacteria and viruses were a result of the fall because of illnesses and disease that occur because of them, but maybe this process of delivering information and acting as a delivery agent was its original design. Maybe bacteria were never intended to harm, but act as assistants to the cell, but after the fall bacteria was introduced as foreign antigens that needed to be killed, and thus the battlefield between the human immune system and these bacteria and viruses began. Just an idea...

    1) I agree with others, that the strengths of this theory could be found in fresh genetic matieral being introduced to the cells. Also, the bacteria acting as "delivery agents" could be viewd almost as the cell's receptionist, running errands for it. The bacteria transport material to and from the cell for efficient functioning. Weaknesses could be that because the bacteria and viruses are still foreign to the body, its a constant battle for the bacteria to fight off the immune system. Also, if the bacteria or the cell malfunctions, maybe it would cause cancer or harmful effects on the cells that bacteria is "delivering" to.

    2) Once again, the immune system was designed to attack and get rid of any foreign antigen in the body. However, maybe the immune system can somehow differentiate between bacteria that is acting as a delivery agent to the cells, and bacteria that is simply parasitic to the body. Or maybe, the immune system builds antibodies to kill every foreign object, but only uses them once the bacteria starts becoming more harmful then helpful. Or maybe, your body is one giant battlefield and the bacteria is only helpful and harmful as long as it can stay alive, then once your body kills it off, other bacteria enters in to take its role as a delivery agent..until its killed off again. a never ending cycle...

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  14. 1) Is it possible that viruses are part of how microevolution occurs? Adaptation is real, it's just macroevolution that is unbiblical. i think that it's possible that the viruses are made to cause genetic change in strong individuals and kill off weaker ones. or possibly , like in the case of sharing proteins with the flu virus, maybe if i was missing a protein, the flu would be good for me if my friend who also had it had the protein and shared it with me through the virus. a weakness of this theory however is that there is no proof of any of this. we are merely speculating. it seems doubtful that such a complex system would work correctly, but if it does, isn't that just further proof of a good design, and not a bad one?

    2) our immune system doesn't try to eliminate ALL viruses and bacteria. Lymphocytes are highly specific to viruses and bacteria. Each lymphocyte binds to only one type of bacteria/virus. Isn't it possible that our bodies have acquired these defenses from thousands of years of adaptation? Say adam didn't have an immune system, because he wouldn't need one, but then acquired it as he got sick with different things, and then it's been passed down and modifeid through each successive generation. If a new virus came, we wouldn't have a defense to it because we wouldn't be able to produce lymphocytes to destroy it. So maybe if a virus isn't bad for you, it won't make you sick and you won't produce a lymphocyte for it. but if a virus caused sickness in an ancestor, you already have that lymphocyte.

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  15. Kayin said this:

    Or maybe, your body is one giant battlefield and the bacteria is only helpful and harmful as long as it can stay alive, then once your body kills it off, other bacteria enters in to take its role as a delivery agent..until its killed off again. a never ending cycle...

    disposable UPS bacteria...I like it.

    March 3, 2011 11:34 AM

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  16. 1. Viruses and bacteria can provide proteins that is lack in the human cells, but the infectious proteins can also be transfered to the cells from the infectious viruses and bacteria.
    2. Could it be our immune system tries to control the amount of proteins that try to transfer to the cell by killing the bacteria and viruses. If there are too many proteins it can initiate autophagy.

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  17. 1. There are the obvious strengths of the theory that it has been seen to happen and that there is evidence towards the change in the cell's DNA due to endosymbiosis. If it does introduce genetic material every time from other people, could we develop similar traits to the other people from which the virus has come in contace? For example could we pick up their allergies, or even their immunities to certain common diseases? Also,a weakness may be that in the example above, the flu virus makes whoever is injected with the virus sick, meaning the organism is rejecting it. Virus, which may have been created as a good thing initially, are now often rejected and used as a way to harm the host cell. This is most likely due to the fall. As not all of the genetic material has been changed, I would be curious to see how much our own genetic material changes over the course of our own life time, and if so, how we haven't drastically changed as a species over a few generations. This would be a flaw I could see in the argument, as we are essentially the same species as we were thousands of years ago.
    2. As I already discussed, it is possible that at the fall viruses use was distorted. Also it could be possible that cells were created to reject all but the most beneficial changes to the DNA, so that in staying the same species we are still as close to God's image as He originally created us, without distorting it.

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  18. 1. As some of my classmates have said, it makes sense to Creationists that God would create something that had a positive function before the Fall, and a largely negative one afterwards. We see this on a macro scale. Take for example the canine teeth in a lion. Why create an animal with teeth for eating meat if there was no meat to eat in the Garden? Or why create the blood thinner that mosquitos secrete if they didn’t need to suck blood? God in His sovereignty designed bacteria and viruses to have a positive role before the Fall, and a mainly negative one after. Remember, He did promise that death would be the result of sin. Viruses and bacteria in their present state often carry death, and that with grim efficiency.

    Evolutionists look at co-option and the different roles of the structures within bacteria and viruses, and they deduce that at some point structures like the flagellum could have been simpler. It is important to remember that this is speculation. We cannot prove that the flagellum has not always done what it does now. But the big question one must ask is this: if the flagellum was not originally a movement structure, what was? Cells still have to move, after all. So to me it seems that to say that the flagellum wasn’t always complex and used for locomotion is all fine and good, except that now we are back where we started since there must have been something that was....

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  19. Like many are saying, our body does attack and try to eliminate viruses and bacteria. (If it didn’t, what would be the point of getting a flu shot...?) However, our body does not try to eliminate all viruses and bacteria. There are helpful bacteria, probiotics, that live in our intestines and are not attacked by our immune system. As discussed in class, this is because the antigens on these bacteria are the same or very very similar to antigens on cells in our body, so that the bacteria don’t stand out as foreign (like Micayla said).

    It seems then that the body doesn’t necessarily recognize things like bacteria and viruses as good or bad, but as foreign or not. Whether or not a delivery agent is helpful doesn’t matter to the immune system.

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  20. The theory makes sense in the way that there are organisms that can help the cell.
    The slight modifications seem to complex to be thought of as an evolutionary process. It could possibly be a slight modification from the consequences of the fall. Once sin entered the world, everything changed, but God knew what would happen and how structures this intricate would work. There seems to be no way to explain this without some thought of intelligent design. It is hard for evolutionists to say that some cells had certain structures that served a different function at first, but then evolved, because this makes the cell extremely complex at the beginning.

    The immune system is able to tell what is harmful to the body and what is not. Harmful substances do not blend in with the other cells in the body. I think that maybe certain bacteria and viruses may stand out which results in the attack of the immune system. The bacteria that are designed to help and are not foreign would be recognized by the immune system.

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  21. 1. The weakness of the theory of a virus or bacteria as an extracellular organelle is that most of the time, viruses are detrimental to the host that they are in, and the significant changes they cause in the host usually cause damage. Also, if it were an organelle, we might observe a mechanism in our body for their creation from scratch, not just reproduction from host cells. The strengths of the theory are that viruses do have unique mechanisms for cellular interaction, and these may have at some point been beneficial to the host cells. As bacteria and viruses can be spread to cause sickness, its possible that they could also spread proteins, cellular parts and genetic information that results in the benefit of the host.
    2. It is possible that if viruses were indeed extracellular organelles, that they would be attacked by the immune system when they are not carrying out the correct function or in the right place. This would be similar to a cancerous cell being attacked by the immune system. Though it is part of the body, it is destructive and thus needs to be destroyed.

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  22. It is quite clear that many bacteria and viruses are "designed" with means to invade cells but why would God design such features in an organism? many creationist would say that this is part of the fall and although that may be true in a sense, it's still a cop-out. Did God purposefully give them these means after the fall, or did they already have them prior to the fall and they served a beneficial function? Or maybe, because of the fall, they developed such mechanisms because life after the fall essentially survival of the fittest; perhaps they could have evolved. As we have seen, there is a certain amount of microevolution that happens within creation i.e there is continuity within discontinuity. It is hard to determine what the possible functions such organisms could have had before the fall since we can't really determine what life was like, on the cellular level, before the fall. It could be that they served to replace genetic material to prevent aging. Is it possible that that viruses were involved in a long-term genetic storage and replacing mechanism? Perhaps after the fall these viruses adapted to more of a survival mode and began to exploit the cells it was designed to enter in the first place.

    It is obvious that viruses are, for the most part, harmful and that our immune systems have developed the ability to recognize harmful pathogens and destroy them. Our immune systems also have the ability to "train" antigens to recognize new pathogens that are harmful. Clearly this ability must have developed shortly after the fall; otherwise humanity would not have lasted long. The question is, did God just implant this ability into man or did we quickly develop these systems in a more evolutionary manor? Either way, I believe that God had a hand in it but I believe that God often uses means within His creation for His purpose. Now this is not to say that He never uses supernatural means but couldn't He use natural means as well? Colossians 1:17 states that God literally holds all things together. If He literally holds everything together than he certainly can manipulate everything on the macroscopic and microscopic level. Perhaps, since He pre-ordained everything that has happened, even before the creation of the earth, that he had already designed organisms so they could quickly develop an immune system. Now all this is more theological than scientific so lets talk a little more about the development of immune system.

    As we know, a developing infant is not already equipped with immunity to microbes it has never been exposed to. Antibodies are passed from the mother to the developing infant to protect it from infection and anti-bodies are continually given to the infant, even after birth through breast milk, until the child can synthesize antibodies on its' own. Hence, immunity is not passed vertically but rather it is passed horizontally. It is not "built in" the information is instead passed from the mother. If the mother was not able to provide the antigens in the first place, the infant would likely die shortly after birth. Just as antibodies are developed to combat specific pathogens, many viruses develop mechanisms and techniques to get around these antibodies. On may acquire a certain glycogen that antibodies use to identify friendly cells. This is an obvious example of microevolution. So does God use some evolution for His purposes? If the world was perfect before the fall than there was probably no room for evolution which could be an additional argument against the old-earth creation theory. But since the fall, there have been some major changes in the way life works and many species have been extinct as a result. There is no doubt that we do indeed live in somewhat of a "survival of the fittest" world and a small amount of evolution is needed to survive.

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  23. (1)I definitely agree with K. Preheim, before the fall, when the world was sinless and perfect, I believe bacteria could have had a beneficial purpose. I am not sure how getting some of someone else’s membrane would be helpful, but I also do not understand God; and we will not understand a world of perfection until heaven. We could sit and discuss what the bacteria could have been according to the microbial extracellular organelle, however, the present reality is that our bodies are still constantly fighting these. This is where the weaknesses come in. Although there are some bacteria that the body keeps alive in the intestines and whatnot, it is still a constant war. These viruses get much more serious than just a cold, they can actually kill a person, people die from the flu every year. It is hard to see how they could be beneficial to the body in any way, because they just seem to harm it.

    (2)Just because something was designed originally for good, does not mean that it still is. The body recognizes that bacteria and viruses, for the most part are not very friendly. The body his trained itself from infancy to recognize these foreign components and attack them, as Jeremiah Dorsey mentioned. Because the other cells of the body have made themselves blend with the rest of the body in order to survive, like Dr. Francis and the scantrons (which kind of sounds like a strange band name), it makes it easier for the body to spot different bacteria, maybe before the fall, the body wouldn’t have killed it because there was nothing that could harm it because the world was absolutely perfect. However, this is not the case now. It is amazing how the body takes the different viruses or bacteria and after infected, uses them to make antibodies. The body cannot do this without having already encountered the bacteria or virus already. This is the point of shots, so the body can make antibodies to protect it in the future. In that way, the immune system doesn’t completely destroy them. Ultimately, because the bacteria and viruses are presently harmful to the body, even though they may have originally been created as beneficial, the body must attack them because of the damage that they do now after the fall, where sin is sin, and things just suck, like viruses and whatnot.

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  24. 1. The strengths of this theory are that it would demonstrate that creation at the beginning was not fighting against its self, rather all organisms at least at the cellular level where benefiting from each other, but since we cannot examine life pre-curse, we can assume that this function although corrupted by the curse allows for life forms to survive in the constant competition that creations is in

    2.Our bodies don't necessarily eliminate every foreign life form that enters, take the digestive system for example it is crawling with bacteria, yet the immune system leaves them alone, I don't think our immune system is mean to keep our bodies sterile of any foreign life form more its like a regulator that keeps everybody where they are supposed to be. For example if bacteria that reside in the colon where put in a open wound infection would surely happen even if in the colon those bacteria are not attacked.

    I will discuss the weaknesses in my second post.

    -David Jaimes

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  25. 2. This could indicate that there is a connection between the theory that bacteria,viruses are intracellular messengers but also intramacro-organism messengers, although corrupted by the fall they still pass on information that could be useful in the future. If pre-fall infections where to happen, I don't think the body would attack those bacteria or viruses but allowed them to go where they usually reside within the body. I'm starting to think that before the fall all of creation was one, in that every organism was part of a bigger picture each one benefiting the other with humans at the top. This just speculation though.

    -David Jaimes

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  26. 1 The cell and the level that it operates is very complex and mostly undiscovered as is obvious through the class of cell biology. I am certain that there are some benefits for bacteria to enter in some cells and bring DNA/proteins. Bacteria roam many areas of the earth and there are most likely areas where for the bacteria to live, it must enter and change a cell for it to live. Some of these bacteria might have vital functions which support life on earth. After the fall this method was probably corrupted bringing this method of infection to areas of life where it is harmful. This is how I would state this theory from a creationist point of view.

    2 An example of this I would say is in the human body and the flu which you mentioned. Here it is harmful and our body’s immune system has been formed to compensate for this problem and eradicate these cells.

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  27. The biggest strength in this theory is the structure of bacteria and viruses. It really does seem like they were designed for more than just infecting cells like delivering proteins or information to a cell. The problem that I see with this however is why? Why would a perfectly normal functioning cell want or need more information from an outside source? And even if it did what are the odds of the right virsus/bacteria infecting that cell at the right time with the right information? Our immune system could try to get rid of these things because they don’t recognize them. Since we aren’t born with them inside of us it doesn’t recognize them and therefore thinks they are foreign bodies—because they are.

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  28. Discuss the microbial extracellular organelle theory as described above. What are its strengths and weaknesses as a theory?
    This makes me wonder...if you get the flu from someone, is it easier for you to receive another sickness from them in the future because you have some of their proteins and membranes in your cells now? In a creepy sense, your friends become a part of your system...curious. And then does that mean that if your friend that got you sick, stayed sick, would you stay sick for just as long, or does each body work individually around the proteins and membranes passed on? hmm.. It reminds me though that we're all fallen and that we're dependent on God to give us, even just every breath that we take. Most everyone named it's strengths and weaknesses.
    2. I think if the immune system senses it as foreign it will attack it and try to get rid of it, but for the most part: if it's recognizable and is seen as not dangerous, it won't do anything to it? Not sure Francis..good question!

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  29. 1. The microbial extracellular organelle theory is that bacteria and viruses deliver agents (genetic material) to cells, and may lead to a genetic diversity because of the acquiring of new proteins. The problem with this is that viruses infect the organism and cause damage to the cell. The strengths it may have is that the virus can enter into the organelle almost like copy of a regular cell and infect the organelle until there is too many of the virus cells to destroy it. Thankfully do to smart scientists and technology; people were able to create vaccines that can destroy the virus quickly, which would be the virus and bacteria’s weakness.
    2. The body’s immune system is to protect it against diseases by killing the pathogens that are trying to infect the body. It eliminates the bacteria and viruses because yes they may deliver some good things, but the body is trying to fight off that foreign cell to protect the organelle. Because of it is a foreign cell, the body’s immune system naturally tries to get rid of it.

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  30. 1. The microbial extracellular organelle theory has many strengths and a few weaknesses. One is that viruses have been shown to be very effective at transporting genetic material between cells without destruction of the cells. Also, the many different specie types we have can be attributed possibly to viruses delivering genetic material within similar genuses. This would explain the great abundance of animal diversity we have without the need for evolution, yet still making it possible for Noah to fit all the animals on the ark.

    Some weaknesses to this theory or rather some questions that have yet to be answered are how does a virus know when to deliver the genetic material, proteins, etc? Also what keeps the virus from lysing its host cell? Because of these questions and the possibility that viruses can be harmful, a microbial extracellular organelle theory almost requires you to be a creationist. Because only in a perfect world where there are no errors can viruses serve the purpose of transport machines between cells without the possibility of harming the host cell.

    2. Dr. Anderson gave me some good insight on this question. He said that the immune system may attack bacteria and viruses when they are deviating from their intended function. For example, when bacteria leaves the GI tract, the immune system will attack the bacteria. Maybe viruses and bacteria only can efficiently transfer genetic material or proteins in certain areas of the human body and if they leave these certain areas then the immune system will destroy them.

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  31. 1 Discuss the microbial extracellular organelle theory as described above. What are its strengths and weaknesses as a theory?

    One of the weaknesses with it is that a very small changes in this could result in a catastrophe of things shutting down due to that one very small mutation. one of its strengths is thatit is able to transport viruses/genetic material between cells without destruction of the cells very effectively.

    2 If bacteria and viruses are designed delivery agents, why does our immune system try to eliminate them? Or does it?

    it tries to eliminate them due to the fact that it probably doesn't recognize them because they are foreign to the body. sometimes they were put in the body on purpose to cause some of the antigens to be destroyed by it, cause maybe they were possibly mutated. it is a natural war for the body to see things it doesn't recognize and try to kill them thats the way we were designed.

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  32. 1 Discuss the microbial extracellular organelle theory as described above. What are its strengths and weaknesses as a theory?
    this is the fact that it can shut down, the good thing about it is that it can transport and carry things such as viruses through and between cells.
    2 If bacteria and viruses are designed delivery agents, why does our immune system try to eliminate them? Or does it?
    our immune system doesnt always recognize the material and therefore acts against it in order to protect no matter what.

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  33. 1. The microbial extracellular organelle theory actually has multiple strengths and benefits. One of these includes the acquiring of new proteins that leads to genetic diversity. Also, it does seem logical that bacteria deliver agents to cells. Another thing that contributes to the strength of this theory is how bacteria have other functions that have something to do with delivery agents to other cells.

    2. Our immune system doesn't simply eliminate all the bacteria or viruses it comes across. For example, some bacteria are actually helpful and beneficial. Therefore, our immune system distinguishes between beneficial and harmful bacteria and eliminates the latter.

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  34. The theory stated is saying that technically every time the flue virus is spread, it takes a piece of the hosts membrane and mutates every time it finds a new home, called antigenic drift. The new stains will take over the pre –existing ones to infect people immune to the old version. I don’t think there is much benefit from this. The virus keeps mutating getting worse and worse. The immune systems is meant to fight off unknown/unwanted intruders and get the problem out, but there are so called “good” bacteria that our body does not fight against. So yes it does eliminate the hurtful bacteria.
    (Just sayin I finished!! Woo hoo!!! Thanks for a fun semester Dr Francis!)

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  35. 1 The strengths of the microbial extracellular theory are that it has numerous functions. It can bind to proteins, act as a motor, and be a receptor at times. This is significant and is strength because this helps the cell do more things. This all could have taken place from adapting to the culture. Another strength is that the there is co-options. It’s amazing that the bacteria can control actin polymerization, inducing the cell pseudopods. The weaknesses are that viruses can be spread throughout so easily and can take certain parts of the cell such as the membrane. This can cause numerous problems if the viruses are bad.
    2 The immune system doesn’t destroy the viruses. It doesn’t destroy it because there are good viruses and bacteria in the body which we need. So the immune system can’t eliminate the viruses. Otherwise it would be getting rid of something our body needs. It’s not known but there could be a way that the body detects bad viruses from good viruses.

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  36. 1. The microbial extracellular organelle theory is basically a theory that when a virus enters your cells it binds to certain things so that when it leaves the cell, it takes along proteins, part of the membrane, and other components of the cell. But, it also leaves some things behind and changes certain things about the cell, so as you said we could be receiving proteins from our friends.
    I would think that one of the disadvantages of the theory are that it could change the chemistry of the cell in a bad way, or deliver a protein that basically shuts down the cell or brings cancer.
    A strength is that the bacteria is so powerful and well designed by the creator as an agent to deliver something, ie. a virus, to the cell; it is just fascinating to learn about. The fact that it can work as a motor, receptor, or binding agent is incredible, especially in something that small.

    2. I would argue that our immune system does not try to eliminate all bacteria and viruses but some can hurt us, so our immune system must react to an unknown bacteria or virus and protect our body from it, especially if it is something that can hurt us. Once our immune system knows that a bacteria or virus is good, it will let it go and if it knows that a bacteria or virus is bad then it will destroy it before it "destroys" us.

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  37. 1. Some strengths are that it could explain an original purpose of pathogens, before sin and the fall. This is obviously a Christian perspective on the matter, but it does make sense. Adding genetic information is not always bad in cells, in fact diversification in genetic material is vital for the continuation of species. If a cell needed certain modifications or extra proteins, bacteria and viruses could import the extra products. The weakness is that most bacteria and viruses are pathogenic and the modifications they make to the genetic code are often times harmful for the cell. Viruses can turn cells into a virus machine, then the cell bursts releasing more viruses and then dies.

    2. Our immune system is programmed to destroy foreign material, usually material that is harmful. The human body is full of helpful bacteria that plays a big role in digestion and the immune system doesn’t eliminate them. This goes to show that the immune system knows what bacteria to leave (possibly based on the carbohydrates covering them) and what foreign invaders to destroy. Obviously immune systems have flaws, which is why we get sick or have allergies. If a bacteria or virus is a legitimate delivery agent, the immune system probably has a mechanism for recognizing “friend” from “foe.”

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  38. Yes our immune system tries to eliminate bacteria and viruses because the role of our immune system is to protect against diseases by killing host cells. But at the same time, parts of our body such as our intestine, has bacterium that live with us. Our body is able to distinguish bacteria that is harmful/useful to our body.

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  39. so i was reading about how our body gets rid of viruses in our bodies and there are 2 types of immune responses: cell mediated and humoral.
    with humoral there is are plasma cells secreting anti bodies specific to the pathogen. these antibodies complex with their specific antigens present on the pathogen and precipitate it out of the circulation. such immune complexes will then be cleared out completely with the help of 'complement' and phagocytic macrophages.
    the cell mediated has cytotoxic T lymphocytes that are involved. these cells prevent the intracellular replication of viruses by releasing special chemicals called interferons.

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  40. Just like there are bad cops and good cops, there are bad mailmen and good ones in our bodies. Our immune system helps regulate the traffic that goes on. Though bacteria and viruses and a pain in the butt to mostly all of us, not all of these irritations are bad. There are good bacteria such as prebiotics, sadly these guys are in constant battle with harmful organisms. So yes, the immune system fends of unwanted bacteria and viruses.

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