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Sunday, February 13, 2011

cell suicide and the schizophrenic Jason Bourne organelle

We are discussing the lipids and proteins which make up the membranes in cells in lecture.  One of the most bizarre membrane proteins is called the mitochondrial permeability transition pore (mPTP).  This is a cluster of proteins which connect the inner mitochondrial membrane with the outer mitochondrial membrane and forms a pore.  The pore only  forms briefly under extreme cell stress conditions and essentially really messes up the mitochondria so that it reverses its function, and begins consuming ATP which  usually kills the cell.   In many cases this activity leads to apoptosis also called programmed cell death. This drastic measure often occurs after local cellular stress or stress of internal organs like during a heart attack.    Just like Jason Bourne in the Bourne Identity, the identity of the mitochondria is difficult to determine, it is a unique mystery organelle in many ways, and like Bourne, it  commits violence when stressed out....or is it that it commits violence to protect itself? Just what could the mitochondria be protecting? 
Questions:
1 What are the different ways that a cell can die?
2 What is apoptosis?  What are its benefits?
3 What would be the advantage to having the vital energy producing organelle also double as a death organelle?
4 Considering the idea that the mitochondria is a specialized internal bacterium, are there parallels in function between  mitochondria and extracellular free living bacteria with respect to energy production and promotion of cell death?


50 comments:

  1. 1. There are basically only two ways that a cell can die. A cell can die from either things outside or things inside. Outside things such as chemicals and tissue-cell damage can kill it. This is called necrosis. Or it can “commit suicide” through programmed cell death called apoptosis.

    2. According to our Cell Biology Text, apoptosis is “characterized by the overall shrinkage in the volume of the cell and its nucleus, the loss of adhesion to neighboring cells, the formation of blebs [irregular bulges in the plasma membrane] at the cell surface, the dissection of the chromatin into small fragments, and the rapid engulfment of the corpse by phagocytosis.” It is triggered by something called caspases which are cysteine proteases and are activated in the early stages of apoptosis to trigger the cell’s death.

    The benefits of apoptosis is that it stops the bad, damaged, defected cells from spreading and multiplying preventing what we know as cancer. Apoptosis also stops the growth of excess nerve cells and the growth of T lymphocytes that react with the body’s own tissues.

    As to the third and fourth question,

    3. I think that the third question has to do with the fact that cancer uses something called the Warburg effect to synthesize ATP and uprise glucose metabolism. It is also called aerobic glycolysis. Mitochondria are the ones who make ATP and without ATP, a cell would die because ATP is the "energy currency" of a cell. It is important that the mitochondria is the one to balance things because it is the maker of the cell's energy and is sort of the lone organelle in the sense that it has its own set of DNA. It is kind of like a secondary check on the first line of defense which is the other cell organelles as well as the DNA in the cell's nucleus. Once the DNA of the nucleus is disrupted or defective it starts to disassemble the cell. But once the mitochondria is affected, then cancer happens?
    4. The fourth question still needs more seeking done on it.

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  2. 1. A cell can die by necrosis or apoptosis. Necrosis is when the cell dies by some injury caused by outside factors. Apoptosis is when the cell kills itself (programmed cell death).

    2. Apoptosis is better than necrosis because it is a way for the cell to die in a controlled manner. Sometimes cells have powerful digestive enzymes inside them (like certain immune cells). If these substances are released during cell death, damage can be done to surrounding tissue. In apoptosis, the timing of cell death is controlled by the cell. An example of this is red blood cells. After 120 days, red blood cells are programmed to kill themselves. This is important because after 120 days, the red blood cells can become toxic. Also, after 120 days, the cells have simply gotten worn out and need to be replaced. Room needs to be made for the new red blood cells that are constantly being produced by the bone marrow.

    3. It makes sense that the energy-producing organelle is the cause of death because the cell cannot live without energy. It is an efficient way for the cell to kill itself. It is also a good way for the cell to kill itself because it preserves the integrity of the cell membrane. This prevents harmful substances from escaping during the process of programmed cell death.

    4. Aerobic bacteria have a similar energy production to mitochondria. I do not know whether there are similarities between bacteria and mitochondria in the promotion of cell death.

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  3. 1. What are the different ways that a cell can die?
    There are two ways in which a cell can die. First, they can be killed by injurious agents. Second, they can induce their own suicide. Basically, they can be killed by either external sources or internal sources.

    2. What is apoptosis?  What are its benefits?
    When a cell undergoes Apoptosis, it shrinks and eventually breaks into small, membrane covered, fragments which release ATP and UTP. The nuclear chromatin (DNA and proteins) break down. This process kills the cell.

    The benefit of apoptosis is that it produces fragments of energy filled pockets. These pockets have receptors which bind to nucleotides that attract them to other cells. Apoptosis creates nutrients for dying cells. “These nucleotides bind to receptors on wandering phagocytic cells like macrophages and dendritic cells and attract them to the dying cells (a "find-me" signal").
    The phospholipid phosphatidylserine, which is normally hidden within the plasma membrane, is exposed on the surface.
    This "eat me" signal is bound by other receptors on the phagocytes which then engulf the cell fragments.”

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  4. 3 What would be the advantage to having the vital energy producing organelle also double as a death organelle?

    If an organelle already contains energy producing properties and is membrane bound, it should be able to produce a controlled release of energy that kills the cell but doesn't completely destroy the cell's nutritional benefit for other cells.

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  5. I like question number 1 the most so I will answer it before I address the others.

    1. Cells are minuscule living beings but some are rather resilient to harsh conditions but mos died from simple things such as excess salt or heat but those aren't very elaborate I would like to know if there are any ridiculous ways that cells are either killed or kill themselves. My favorite suicidal cell is the human white blood cells that selflessly eat bacteria and most of the time die from doing so because they explode. I bet there are many other cells that also have very elaborate suicides.

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  6. For question 4: From the evolution model of origins, the mitochondria is supposed to have been a bacterium ingested by a cell that survived digestion and became responsible for the cell's energy production. This assumption is partly based on the similarities found in the DNA of bacteria and mitochondria. Since proteins are determined by DNA, and apoptosis is initiated by a protein, I would conclude that the bacteria and mitochondria do share similarities in the promotion of cell death.

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  7. Q1&2 There are only two ways for cell to die, first is they are destroyed by injurior (Neucrosis)and second is they undergo self destruction (Apoptosis). Apoptosis is the mechanism that trigger the internal and external receptor of the cell to form destruction. The benefits from doing that are important for the organisms' development and to protect the organisms from the threat of cell's corruption function.

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  8. 1. Cells can die by apoptosis (cell programmed death) or external, harmful sources, like toxic chemicals for example. I also read that cells can die by DNA replication without telomerase, or DNA mutations. These would happen from within the cell, but are not part of apoptosis.

    2. Apoptosis when cells shrink, develop bubbles on it's surface, and the chromatin in it's nucleus is degraded. Then, the cells release crytochrome c which degrades mitochondria, and breaks down into smaller pieces. It then releases ATP and UTP, which binds to receptors and goes back to the dying cell. The phospholipid phosphatidylserine (which is normally hidden in the plasma membrane comes to the surface of the cell and binds to other phagocytes and engulf or "eat" the cell pieces. Then the phagocytic cells secrete cytokine that prohibit swelling. Benefits of apoptosis are that when a cell is old and not doing a good job of what it is supposed to do, then it can just self destruct. Another example of when apoptosis is beneficial is when a tadpole is ready to get rid of it's tail, it uses apoptosis to get rid of it's tail. It could also be helpful when it needs to get rid of a cell because it is infected with a virus or other infectious agent.

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  9. 3. Mitochondria is involved with energy production as well as cell death. I think the answer to this question is similar to what I said for #2. In the case of the tadpole, since the cells need a way of energy to grow quickly, it also makes sense that they would need a way to stop it's growth quickly and make the cell die so the tail goes away. Also, if the cell is infected with a virus or some other harmful substance, it could just self-destruct without having to wait for other mechanisms to find that cell to destroy it. This is just a thought. I'm sure God had a really good reason for it though!

    4. Some think that mitochondria evolved from bacteria, so it would make sense that the two are related. For scientists to think that one evolved from the other must mean that they have things in common. This is related to the endosymbiotic theory, which says "certain organelles originated as free-living bacteria that were taken inside another cell as endosymbionts". Ivan Wallin was the scientist who took ideas on this topic of endosymbiosis and applied it to mitochondria. Similarities of bacteria and mitochondria is that they have 2 or more membranes and have some of the same ribosomes. Also, bacteria plastids and mitochondria are both formed through binary fission. Very interesting!

    http://en.wikipedia.org/wiki/Endosymbiotic_theory

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  10. 1. Cells either die from necrosis (outside factors) or apoptosis (from within). While necrosis typically occurs in a traumatic way and the cells can rupture, apoptosis is usually carried out in a neat orderly fashion in which all of the cells contents remain contained.
    2. Apoptosis is caused by intracellular or extracellular signals. Extracellular signals include toxins, hormones, growth factors, and nitric oxide. Hormones are released to signal cells to apoptose to shape the body during growth, which is one example of apoptosis' usefulness. Intracellular causes can be triggered by a number of different things, but often it involves either mitochondria or Ca+ poisoning with the help of calcium binding protease calpain. Self-induced cell death is helpful in stopping genetically mutated or infected cells from spreading throughout the organism.
    During apoptosis the cell begins to shrink and the nucleus condenses resulting in enclosed fragments of the cell called apoptic bodies breaking off to be consumed by other cells so that the materials from the cell can be reused.
    3. Mitochondria are energy producing proteins and function very quickly. Maybe their speedy metabolic reactions account for how fast apoptosis occurs?
    4. Mitochondria are similar to aerobic bacteria. Many of the functions mitochondria perform in apoptosis involve chemical messengers manipulating the permeability of the mitochondrial membrane which cause it to release pro-apoptic proteins. One of these chemical messengers is nitric oxide which dissipated the mitochondria’s membrane’s permeability allowing the specific proteins that bind to inhibitor of apoptosis proteins (IAP’s) allowing enzymes to essentially take apart the cell. So if nitric oxide has the same effect on aerobic bacteria that it does on mitochondria, and if these bacteria exist around other eukaryotic cells, could you introduce them to high amounts of nitric oxide and have the bacteria release these pro-apoptic proteins and make all of the surrounding eukaryotic cells self-destruct? It’s really the only connection between this process and the bacteria that I can see.

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  11. Micayla,

    You commented:

    Some think that mitochondria evolved from bacteria, so it would make sense that the two are related. For scientists to think that one evolved from the other must mean that they have things in common. This is related to the endosymbiotic theory, which says "certain organelles originated as free-living bacteria that were taken inside another cell as endosymbionts". Ivan Wallin was the scientist who took ideas on this topic of endosymbiosis and applied it to mitochondria. Similarities of bacteria and mitochondria is that they have 2 or more membranes and have some of the same ribosomes. Also, bacteria plastids and mitochondria are both formed through binary fission. Very interesting!

    Could they be similar for other reasons?
    Dr Francis

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  12. Yes, now I see that mitochondria and free-living procaryotic organisms can be similar because they both have DNA and ribosomes, reproduce, and make proteins. It's almost like the mitochondria is a mini cell...
    www.ac.ly/vb/attachment.php?attachmentid=981&d=1251725668

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  13. Do you mind a comment from a former student? A real-world example of when apoptosis is beneficial: http://www.facebook.com/album.php?aid=34608&id=595571692&l=9cbb91ea0c See the third photo in the album. If not for apoptosis, we'd all look like this. The fact that apoptosis did NOT occur in this situation was beneficial to us because it was the only way we could tell the twins apart for over a year.

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  14. Thanks Clark family...please join our discussions...is this R and S? (used first initials only)

    Dr Francis

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  15. 1) In necrosis, outside agents "murder" the cell. Apoptosis is a cell committing suicide.
    2) During apoptosis, cells shrink, destroy their chromatin,break down their mitochondria and release integral membrane proteins. These break down the cell into smaller fragments. The explosion of the cell releases ATP and UTP. These in turn bind to bind to other cells and tell them that a cell is near by. PS sticks out of the fragments and tells the nearby cells to eat it. and so the cell dies....
    apoptosis is instrumental in killing cells that have become harmful to the organism. All viruses would be deadly if not for apoptosis. Also, if not for apoptosis, we wouldn't have fingers or toes, like the clark family pointed out. Reproduction also couldn't happen, because there would be no menstrual cycle. Basically, you can't have development without death.
    3) Cytochrome C, which is the enzyme that tells other cells to eat the suicidal cell during apoptosis, is also a vital part of life. It controls the electron transport train. It is efficient for the cell to use the same organelle for two seemingly opposite processes.
    4)Both Prokaryotic organisms and mitochondria undergo binary fission, are about the same size,have the same type of chromosomes and ribosomes. it seems like they would also have similarities in cell death and function to, but i can't fin them. :(

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  16. Yes! This is Sumiko. Thanks for letting me join...I miss it! This would be a great way for me to review it all. Unfortunately, after 6 1/2 years, I've forgotten a lot of it.

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  17. 1) Necrosis: “The death of most or all of the cells in an organ or tissue due to disease, injury, or failure of the blood supply.”
    New Oxford American Dictionary.

    Apoptosis: “The death of cells that occurs as a normal and controlled part of an organism's growth or development.”
    New Oxford American Dictionary.

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  18. 2) Generally speaking, apoptosis gets rid of unnecessary cells (like used, antigen-specific lymphocytes that the immune system no longer needs). This makes space for new cells.

    During the development of an embryo, apoptosis is used to form the body parts (feet, toes, etc) of the future mature form of the growing organism. Apoptosis also prevents the atrophy or degeneration of the embryos various members.

    When a cell dies by necrosis it can release chemicals that trigger a response from the body’s immune system, causing inflammation of the tissues around the dead or dying cell. Fortunately, when a cell dies by apoptosis the body does not respond the same way, and no inflammation occurs.

    Sources:

    Apoptosis and the Balance of Homeostatic and Pathologic Responses to Protozoan Infection. L. Cristina Gavrilescu and Eric Y. Denkers.

    University of Washington. "How Do Infections And Toxins Launch A Cell's Self-destruct And Alarm System?." ScienceDaily 14 March 2008. 17 February 2011 .

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  19. 3) If the most important organelle is the initiator of cell suicide, that prevents stressed -- but not completely hopeless -- cells from dying when they may still have a chance to survive. For example, it wouldn’t be helpful to have cells destructing that had healthy mitochondria, but a damaged vacuole. Only after the most vital organelle failed would the cell finally be destroyed.

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  20. 4) Since both mitochondria and bacteria have apoptosis, and both have respiration (the obtaining of energy), there are parallels between mitochondria and bacteria.

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  21. Sam, do bacteria undergo apoptosis? if so provide reference...would like to see that.

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  22. 1. The two different ways a cell can die are injury and suicide. They can have mechanical damage or be exposed to a toxic substance and thereby die from injury to the plasma membrane or even the contents inside the cell. It can also die by suicide, which is apoptosis. It is induced to commit suicide and there are many different ways that it does this, or different ways that the cell looks and acts in the process of committing suicide.
    2.Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. Its benefits are that it is as needed for proper development (it is needed just as much as mitosis is needed) and it is needed to destroy cells that represent a threat to the integrity of the organism.
    3. Well the advantage would be that the cell needs energy so it gives the cell energy but if something damages the cell it can quickly cause death in the cell and it actually has benefits as discussed earlier.
    4. Evolution believes that in the endosymbiotic theory, developing eukaryotic cells engulfed aerobic bacteria and those are the modern day mitochondria. Now we as creationists know that God created mitochondria and nothing evolved but there are still similarities between the two that should be recognized. These free bacteria are both involved in respiration which is a major energy source for a cell as well as for an organism. Both of these are created to energize something whether it is themselves or a larger organisms, or both. I'm guessing that if they sense that something is wrong, both the mitochondria and the bacteria can shut down and since they are a vital energy sourcce, they will cut off the life of the cell. The more I look the more I see similarities between these two yet there are differences but instead of pointing to evolution it points to a Creator who created them to be similar.

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  23. 1. Cells can die through external influences, such as being separated from the body, or infected with a virus and lysing, or they can die from internal influences, such as programmed cell death when the body needs to lose the cell.
    2. Apoptosis is programmed cell death, and an example of it being useful is the death of cells during embryological development, such as when digits are formed or the tail of a tadpole is removed. The benefits are the convenient removal of cells that are no longer necessary for the organism. Apoptosis is also a component in the immune system, in that infected or damaged cells can kill themselves to prevent surrounding cells from being damaged as well.
    3. It was mentioned that the mitochondria can begin consuming ATP during stress such as a heart attack. During a heart attack, cells in the heart begin to die after not having enough oxygen; a major component in the synthesis of ATP. It could be that when not enough oxygen is supplied to keep every cell in the heart alive, the highest priority cells are kept alive and the less important cells reverse the synthesis of ATP so that oxygen is not consumed.
    4. Bacteria are similar to mitochondria in their metabolic pathways, and the endosymbiotic theory suggests that mitochondria used to be free living bacteria. In light of mitochondrial self destruction, that would be difficult to explain with the endosymbiotic theory. Bacteria are a form of unicellular life, so there seems to be no real benefit for bacterial apoptosis, and it is not commonly seen in nature.

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  24. There are many different forms in which a cell can die. One is where cells detach from the extracellular matrix, receptors overreacting and resulting in too much of an ion can kill a cell. Autophagy is where a cell releases the substances in a lysosome which cause it to digest itself. Also there is Apoptosis where the cell is programmed to die which can be beneficial.

    Apoptosis is programmed cell death or where the cell plans to die and kills itself. The cell first creates many proteins called caspases which break down many cellular parts and cause other enzymes to increase. The cell begins to shrink and the cytoskeleton and nucleus begin to be broken down. The cell condenses allowing easy “pick-up” of the dead cell. The cell undergoes this process when it experiences stress or viral infection. In these cases it would be beneficial for the cell to die for the organism to prevent the cell from becoming cancerous or infecting other cells.

    It is efficient for the mitochondria to kill the cell for many reasons. Since the mitochondrion produces the energy for the cell nothing can proceed without it. The mitochondrion is the first thing you want dead in a cell otherwise you have energy floating around creating things to happen that shouldn’t be. This provides a fast and efficient way to kill the cell without any unwanted reactions from occurring.

    Bacteria and mitochondria have many similarities from a physical standpoint. Mitochondria are relatively the same size as bacteria and both contain the same structure of DNA being a clumped loop. Since structure and function are always related in the micro level this gives rise to the ideas that a mitochondria was once a bacteria. Some functions that are similar are that mitochondria have similar transport systems and enzymes as some prokaryotes. There are numerous other similarities like similar ribosome’s, tRNA’s, and antibiotic sensitivity. These are some reasons why the endosymbiosis theory is so widely believed.

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  25. 1 What are the different ways that a cell can die?
    I found on editorial on cell death and differentiation (http://www.nature.com/cdd/journal/v12/n2s/full/4401781a.html) and according to it “it is possible to discriminate up to 11 pathways of cell death occurring in mammals, 10 of which are genetically programmed.” If a cell is genetically programmed to die it is called cell suicide and they can “commit suicide” in several different ways. The cell can shrink, have the chromatin degraded, break down the mitochondria, release ATP and UTP, and several other ways.

    2 What is apoptosis?  What are its benefits?
    According to the same editorial on cell death and differentiation “apoptosis is a developmental remodeling program and a defensive, organized self-destruction of the cell in reaction to severe damage.” As said above, apoptosis is cell suicide. There are two different reasons that I have found why a cell might want to commit suicide. (1) It is needed for proper development. For example, a tadpole goes through apoptosis to get rid of it’s tail. (2) It Is needed to destroy cells that represent a threat to the organism. For example, cells containing viruses, cancer cells, or cells with DNA damage.

    3 What would be the advantage to having the vital energy producing organelle also double as a death organelle?
    Without energy, a cell will die. Essentially a cell can survive without almost every organelle, albeit a strained survival but a survival, but once the mitochondria stops providing energy the cell will die. It is the same as a human and his heart, once the heart stops pumping blood, life’s energy, the human dies. If a cell had to die, the mitochondria would be the organelle to kill it. Its function is the most needed.


    4 Considering the idea that the mitochondria is a specialized internal bacterium, are there parallels in function between  mitochondria and extracellular free living bacteria with respect to energy production and promotion of cell death?
    Bacteria have no internal organelles, so they promote energy on their own, both bacteria and mitochondria are able to create energy. I’m sure many evolutionist say that eukaryotic cells used the bacteria for an energy source, but as Dr. Francis said in the e-mail, there must be a reason we need such energy producing entities outside and inside the cell. Here is an interesting sight where they seek to prove that the endosymbiotic theory is false http://creation.com/mitochondria-created-to-energize-us. The main difference is that bacteria are self-sufficient, but mitochondria, though they have their own DNA, are far from being self-sufficient, they still rely on the nucleus of the cell they reside in. It is clear that because bacteria are similar to mitochondria they are able to live on their own, otherwise they could not create energy, but they still are more complex than mitochondria. They contain what is needed to live a self-sufficient life. In light of endosymbiotic theory this makes no sense. How would something become less complex after a symbiotic relationship began? It wouldn’t. According to evolution it would become more complex.

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  26. 1) Cells can die either externally or internally. They can be killed by injurious agents or can 'program' to die (suicide).

    2) Apostosis is programmed cell death. Upon receiving specific signals (due to developmental cues, stress, or damage to vital cellular components), the cell undergoes a number of changes. The cell shrinks and its chromatin is broken down. Apoptosis is the most common way that the body eliminates damages or unneeded cells. It plays a role in human embryonic development and homeostasis.

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  27. 1: cells can die two different ways, death by injury, or death by suicide that has been induced. Death by injury occurs when there has been mechanical damage or exposure to toxic chemicals. Death by suicide occurs by shrinking, developing bubbles on their surface, they may have the mitochondria break down the release of cytochrome c, they can break into smaller membrane-wrapped fragments, release ATP and UTP, the phagocytic cells secrete cytokines that inhibit inflammation of the cell.
    2: Apoptosis is the process of programmed cell death that occurs in multicellular organisms. The benefits of apoptosis being able to occur is that the one deformed, mutated cell that is causing other cells to die because it’s not carrying out the function that it was made for, can be killed before it gets a chance to cause other cells to not perform their functions.
    3: If the energy producing organelle could also double as a death organelle, the advantage would be that the more cells wouldn’t die. For example, when there is a cancerous and chemo is in the body it just kills a bunch of cells rather than just the mutated cells. If the organelle was programmed to be able to double as a death organelle, then cancer would be less common because there wouldn’t be as many out of control mutated cells growing in humans.
    4: The only parallels I can see between mitochondria and extracellular free-living bacteria would be that they both produce energy. I think that by the cell giving off ATP, it could cause it to commit ‘cell suicide’ and die. This would then directly relate to the promotion of cell death.

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  28. My bad. Bacteria do NOT undergo apoptosis. It seems, however, that they can cause apoptosis in eukaryotic cells.

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  29. 1, There are two types of PCD's (programmed cell death), one would be Apoptosis, the other Autophagic. Autrophic factors such as things that can cause great stress on the cell, also contribute to cell death.

    2. "Biochemical events lead to characteristic cell changes (morphology) and death. These changes include blebbing, loss of cell membrane asymmetry and attachment, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation. " One advantage of Apoptosis includes cell differentiation during the development of an organism.

    3. An advantage of having a major energy producing organelle, such as the mitochondria, act as a death organelle would be a quick termination of the cell. In the case of infection, this could potentially help prevent the spread of a virus or harmful bacteria??

    4. I'm sure there are some parallels between the two...I just don't feel informed enough about the topic to answer the question. XD

    -Sarah Gonzales

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  30. 1. Cells can die from starvation or toxin to viral infections. If there is not enough particular nutrients the cell will malfunction, and if there is too much of nutrients it will initiate autophagy and early cell death.
    2. Apoptosis is cell death so the new cell can regenerate. Certain cells will need to apoptosis when the embryo develops if the cells fail to apoptosis it may cause deformity in the growing embryo.

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  31. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Apoptosis.html

    reference

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  32. 1. Cells can die in a myriad of ways including: necrosis which is caused by external means such as infections, toxins, or trauma, and apoptosis which is usually caused by internal means and is usually done in benefit of the organism. Apoptosis can be caused for a number of reasons and shows up in many different ways. For example autophagy is a catabolic (the process of breaking down complexes into more basic units whilst releasing energy) process where the cell breaks down its own components via lysosomal activity.

    2. Apoptosis, in simplified terms, is programmed cell death. Lysosomes inside of the cell engulf all of the different parts of the cell. Some benefits of apoptosis includes: providing room for new cells, it also prevents DNA damaged cells from reproducing, thus minimizing the development of cancerous cells.

    3. The mitochondria powers the Cells through the production of ATP, so if this same organelle begins to use up the ATP in reverse instead of making it, the cell can die very quickly through lack of ATP and also it is able to fuel the process itself. Also if cancerous cells need ATP to reproduce, then the usage of the ATP prevents the cancerous cells from reproducing.

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  33. 1 What are the different ways that a cell can die?
    Cells can die in two ways: either through injury by a toxic chemical or mechanical damage. Another way they can die is when the cell induces cell suicide.

    2 What is apoptosis? What are its benefits?
    Apoptosis is a process where Cells are induced to commit suicide. Its benefits are that it is needed for proper development. An example includes the formation of toes and feet of a fetus and apoptosis occurs the kills the tissue cells in between them. Another benefit is that it is needed to destroy cells that represent a threat to the integrity of the organism. Examples of this benefit include Cells infected with viruses, Cells of the immune system, and Cells with DNA damage.
    3 What would be the advantage to having the vital energy producing organelle also double as a death organelle?
    The advantage of having an organelle serve as the an energy source and double as a death organelle is that it has the power to kill itself. It can use the energy it produces to induce suicide for the benefit of the cell without infecting other cells. An example is cells of the immune system having the effector cells be removed to prevent them from attacking body constituents.

    4 Considering the idea that the mitochondria is a specialized internal bacterium, are there parallels in function between mitochondria and extracellular free living bacteria with respect to energy production and promotion of cell death?
    There is a parallel between the two in respect to cell death. In an online medical journal, it was written that there are two kinds of genetic programs that promote bacterial cell death. The first is a toxin–antitoxin module found in the chromosomes of many kinds of bacteria. The second is found in Bacillus subtilis, in which the skfand sdp operons mediate the death of a subpopulation of sporulating bacterial cells.

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626106/
    http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Apoptosis.html

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  34. there are two ways a cell can die, either by injury or if they are induced to suicide.

    apoptosis is the process of programmed cell death, suicide. some benefits may be that through the process of cell suicide it removes unwanted cells.

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  35. 3 What would be the advantage to having the vital energy producing organelle also double as a death organelle?
    I feel like number 3 is would be the same answer as number 2: If a cell is sick or needs to die off, I would think that it's a natural process that needs to occur..if it didn't occur, then that would be how tumors start. Tumors are just masses of cells that don't stop growing, a defect in the mitochondria I guess! Praise the Lord that the cell can both grow and die out!

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  36. A cell can die from a number of things but it basically boils down to external or internal stimulus that can kill a cell. An example of external would be chemicals or tissue damage. An example of internal would be the cellular organelles malfunctioning like described in the blog.
    Apoptosis is the process of programmed cell death. This could be beneficial because it could stop the replication and usage of damaged cells in the body.
    The benefit of having the energy producing organelle also be responsible for death is that it would provide a quick and certain death. If you cut off the energy then all of the cell will die no matter what and will go rather quickly.
    Mitochondria and aerobic bacterial cells have some similarities like they both undergo binary fission and they have some of the same organelles like chromosomes and ribosomes. Because of this it would make sense for them to have similarities in how they function in cell death.

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  37. 1. Cell death can occur in many different ways, but all of these modes of cell death can be divided into two groups: outside factors or internal factors.
    2. Apoptosis is programmed cell death. A cell initiates apopotisis for a variety of reasons including blebbing, loss of cell membrane, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation. Signals that control apoptosis can either be extracellular or intracellular. Extracellular signals include toxins, hormones, growth factors, nitric oxide, or cytokines. Intracellular signals begin in a cell in response to heat, radiation nutrient deprivation, viral infection, hypoxia, and increased intracellular calcium concentration.

    The benefit of apoptosis is that it protects the organism from cells that could become harmful to the organism. Such cells include cancerous cells as well as virus infected cells. Also apoptosis is important in separation of the fingers and toes in a developing embryo.
    3. It is beneficial to have the mitochondria to act as the death organelle, because the first step in cell death should be to stop energy production. If energy production is halted then the cell won’t be able to accomplish any other functions including cell replication, production of viruses, or formation of dangerous proteins. This is very important because if cell processes continue then the infection or cancer can spread.
    4. In a study done in 2002 “several key enzymes of the apoptotic machinery including the paracaspase and metacapase families of the caspase-like protease superfamily, apoptotic ATPases and NACHT family NTPases, and mitochondrial HtrA-like proteases.” This study also found these proteins are abundant in actinomycetes, cyanobacteria, and alpha-proteobacteria. Alpha-proteobacteria specifically applies because it is considered an ancestor of the mitochondria.

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  38. 1 What are the different ways that a cell can die?

    A cell can die in many ways here are some, through infection, poisoning, overheating or lack of oxygen. the cell can swells up, and its contents leak away. This may damage surrounding cells. But there is another,way to go programmed self- detonate, or apoptosis. It seems that cells often choose to kill themselves.

    2 What is apoptosis? What are its benefits?

    it is the loss of cell membrane, cell shrinkage, nuclear fragmenting,this way is allot safer for the, cell apoptosis produces cell fragments called apoptotic bodies that circle cells which then are able to engulf and quickly destroy and remove before the contents of the cell can spill out onto surrounding cells and cause damage.

    3 What would be the advantage to having the vital energy producing organelle also double as a death organelle?

    they bring a higher level of complexity to the cell they also provide a easy way to dispose of the dead cells by way of recycling their materials for further use in the cell.

    4 Considering the idea that the mitochondria is a specialized internal bacterium, are there parallels in function between mitochondria and extracellular free living bacteria with respect to energy production and promotion of cell death?

    There are only two parallels I can see between mitochondria and extracellular free bacteria would that both produce energy. that by the cell giving off ATP, it could cause it to commit ‘cell suicide’ and die. This would relate to the of cell death.

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  39. 1. I honestly don't see the point of answering the first question at this point because it has already been answered multiple times and I've pretty much come up with the same answer with the rest. I also don't have that much to add to it. But yes, necrosis and apoptosis are the two ways a cell can die.

    2. Apoptosis is a process in cells (I believe this only occurs in multicellular organisms) in which it is programmed to "kill itself." In other words, it is a programmed cell death. This can occur through a series of biochemical processes or events that lead to changes in a cell's characteristics (called morphology) and, eventually, death. Pretty much the advantages found in apoptosis lies in that cells can kill themselves when they need to. This is beneficial in multiple ways, from simply not having webbed toes and fingers, to something as important as having certain parts of organs not swelling up too much. Also one thing to note is that excessive apoptosis leads to atrophy, while too little apoptosis may lead to cancer.

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  40. Questions:
    1 What are the different ways that a cell can die?
    well, it depends on the cell.

    SOME cells will go into a kind of hibernation when you starve them and re-awaken when conditions are more favourable.

    others, will chug along till they die.

    the cause of death is actually surprisingly complex and will vary from cell to cell. ultimately, there are certain functions a cell has to carry out to maintain its life, mostly repairing damage that naturally accumulates and replenishing chemicals it uses up to keep active. if there are no resources to repair itself then it will die because of accumulated damage and if it cannot replenish certain chemicals it will die because it cannot maintain a chemical equilibrium in itself.

    then you have to factor in the whole 'what is alive?' factor because at the cellular level it starts getting a bit fuzzy.
    http://www.scienceforums.net/topic/52339-how-does-a-cell-die/
    2 What is apoptosis? What are its benefits?
    a type of cell death in which the cell uses specialized cellular machinery to kill itself; a cell suicide mechanism that enables metazoans to control cell number and eliminate cells that threaten the animal's survival

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  41. 1.) The different ways that a cell can die is by killing them through injurious agents or inducing them to commit suicide. The apoptotic pathways are extrinsic and intrinsic. When cells die by injury, they swell because the pathway in the plasma membrane, in which the ions and water pass through, is disrupted. However, when cells are induced to commit suicide, they shrink in size, the chromatin in their nucleus is degraded, and the cells break into small, membrane-wrapped fragments.
    2.) Apoptosis is the programmed cell death by the fragmentation of nuclear DNA. Apoptosis can be induced either by toxic drugs or by removal of a repressor agent. The disintegrated cells are then eliminated by phagocytosis. Unlike necrosis, another form of cell death, apoptosis is a process in which cells play an active role in their own death- cell suicide. During the process of cell death, some of the changes include losing of cell membrane asymmetry and attachment, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation. Also apoptosis is an energy-dependent process. It requires the activation of caspases, group of cysteine proteases, and “a complex cascade of events that link the initiating stimuli to the final demise of the cell” (Elmore). The benefits of cell death are that apoptosis maintains cell populations in tissues, and acts as a defense mechanism such as when cells are damaged by disease or noxious agents.
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2117903/

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  42. There are only two ways presented that a cell can die, one is suicide called apoptosis, or from an injury from outside the cell called necrosis. The benefit of apoptosis is that the cell controls its death and can do it in a safe organized matter that will protect its surroundings. Summed up, the cell will shrink, tear down their chromatin and mitochondria than release ATP and UTP that will bind to another cell that will use phagocytosis to kill it off. The cell being engulfed gives off ATP giving the nearby cell energy, benefitting everyone! Well mitochondria is the powerhouse of the cell producing ATP and with a bacteria not having mitochondria, I believe that the bacteria could use its energy.

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  43. 1. Cells can die from disorder or dysfunction, if a process within the cell goes wrong, often the cell cannot survive and it dies. Also, it can die from too much or too little water. Lastly, it has a designed process for killing excess cells. This sort of “cell suicide” is to prevent cancer from developing due to excessive cell growth.

    2. “Apoptosis, or programmed cell death, is a normal component of the development and health of multicellular organisms. Cells die in response to a variety of stimuli and during apoptosis they do so in a controlled, regulated fashion. This makes apoptosis distinct from another form of cell death called necrosis in which uncontrolled cell death leads to lysis of cells, inflammatory responses and, potentially, to serious health problems. Apoptosis, by contrast, is a process in which cells play an active role in their own death (which is why apoptosis is often referred to as cell suicide).”
    http://www.sgul.ac.uk/depts/immunology/~dash/apoptosis/

    Like I said before, programmed cell death helps the function of the total organism run more smoothly because excess cells are killed off, making room for the new high-functioning cells. Without this process of apoptosis, cells would reproduce uncontrollably and cause cancer.

    3. Ok I’m going to purely speculate on this, but it makes sense to me that the thing that provides respiration and energy to the cell would be the thing that signals its death because its an extremely vital organ. The cell would take a lot longer to die if it started dying off one ribosome at a time or something. Not to be morbid, but it’s like killing yourself by chopping off one limb at a time, or just going straight for the heart. It would simply seem to be more efficient for the cell’s mitochondria to start the process of apoptosis.

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  44. 1 Cell can die by mutations in any of the cells parts. One well known mutations is when the cells over multiply (also known as cancer). Another way a cell can die is by a problem in the many cell machines in the cell. Also a cell can die from toxic chemicals.
    2 Apoptosis is programmed cell death. The pattern of events in death by suicide is so orderly that the process is often called programmed cell death or PCD. The cellular machinery of programmed cell death turns out to be as intrinsic to the cell. The benefits are that this promotes growth factors for neurons.
    3 If it stops producing energy the cell dies anyways. So you want to at least get something. The cell death doesn’t matter unless the cell is being productive.
    4 The apoptosis is triggered by internal signals in the mitochondrial pathway this is similar to extracellular living bacteria in energy production and promotion to cell death because a signal is sent in both cases.

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  45. 3. Cells have a defined space for existing and thus an extra organelle dedicated to suicide seems like a waste of space. But what better place than the energy producing organelle to have a self destruct button. This allows for a quick death for the cell because as soon as self destruct would be initiated the production o energy would cease but lets say it was located elsewhere in the cell it would take more time for the kill message to be received all while the mitochondria would work against the dying cell by continuing to produce energy.

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  46. 1. A cell can die in two ways: Apoptosis and necrosis. Apoptosis is the self-destruction of a cell, and necrosis is destruction from an outside source.
    2. Apoptosis is the process of programmed cell death. Apoptosis kills infected cells, cancerous cells, or cells in the wrong place in development. This prevents unhealthy cells from existing and consequently sustains human life.
    3. It could be the advantage because if the cell messes up and causes cancerous cells, it can nip the infection or uninhibited growth in the bud as the energy produced by the mitochondria will be used for the apoptosis.
    4. Mitochondria are believed to have come from a bacteria which was engulfed in endocytosis. There are multiple similarities in structures, but a similarity in the creation of energy is that bacteria have a similar electron transport chain to the mitochondria. There are other similarities as well. I could not find any similarities between the cell death pathways of mitochondria and bacteria.

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  47. There are two ways that a cell can die: necrosis or apoptosis. Apoptosis is from an outside factor and necrosis is self destruction.

    Apoptosis is self-destruction in the cell, it is a programed process where the cell loses adhesion to other cells or the matrix and shrinks 'till it breaks down and is consumed by other cells to be recycled. It benefits cellular life because cels that have mutations or are just unhealthy and need to be replaced can be.

    Since the mitochondria creates energy, which it needs in order to live, so the mitochondria allows for a quick death of the cell.

    In an evolutionary model, this would make sense, at least as far as producing energy goes because there are certain bacteria that produce energy in a similar way. I'm not sure if that is consistent with the cell death programing because as far as I know there aren't any bacteria that are programed for destruction.

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  48. 1 What are the different ways that a cell can die?
    there are two possible ways for a cell to die, from the outside, which is necrosis or from the inside which is apoptosis.

    2 What is apoptosis?  What are its benefits?
    apoptosis is where a cell dies from within. the cells shrinks. this process allows the cell to die without harming the organism, because it is being told to die. it is all part of the cycle of life.

    3 What would be the advantage to having the vital energy producing organelle also double as a death organelle?
    It removes the need for an added device. Without energy, the cell dies. All the organelle needs to do is cut off the energy supply. Its that simple. it is also speedy.

    4 Considering the idea that the mitochondria is a specialized internal bacterium, are there parallels in function between  mitochondria and extracellular free living bacteria with respect to energy production and promotion of cell death?
    this idea was sort of addressed in a previous blog. one theory would be that the some bacteria break things down, and the mitochondria breaks the cell down. This similarity in function is something i thought that might be interesting. most other points have already been hit by everyone else.

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  49. Apoptosis is a programmed cell death and it is easily defined when contrasted with necrosis. Necrosis is when a cell dies because of a traumatic accident, like overheating or being poisoned. Apoptosis is when the cell actually plans to die, the opposite of necrosis.
    The advantage of having the vital energy producing organelle double as a death organelle makes everything run orderly in a multicellular organism. This also prevents overpopulation of the cell, in case none of the cells go through necrosis.

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  50. There are 2 ways a cell can die, one it could die like a brave firefighter whose death was caused by the things which surround it, this type of cell death is called necrosis. The other way a cell can die is more or less the same way a suicide bomber dies, through suicide, cell suicide, death from within is called apoptosis. Cell-wise, apoptosis is caused not of an explosion, but a shrinkage, its like self done hypertonic solution stuff. Though this is a plus, because though it causes the destruction or death of a cell, it mostly targets, cells who don't contribute or cannot seem to function correctly anymore.

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