Ahmad

I have something in my mind. Maybe I should think more about it. But I'm thinking that this is not a simple division over the number of plants you have. The probability here is for a multiple step process, where you multiply each steps probability by the other, assuming in each step that the previous one occured. So, just maybe, by each planet you add, you are lessening the probability of the steps to occur in a single planet. I mean, if one step occurs in one planet, and the other occurs in the other, then it's of no use.

Hmmm. Now start thinking about a human being with all its complexities. How a single cell can give raise to functoining human being. Not only that, think of the environment as a whole. Some plants need some insects to reproduce, and these insects need them to survive.

Donkey + Horse = Mule Mules cannot reproduce for genetic reasons. Yet they still exist. It doesn't have to be a simple Mendelian rule to be genetic.

You set what to print the errors? You mean it is an option in the script? This is obviously a problem in the execution of the script itself. Anyway, I might be able to help you if you get me the error messages. Just look for the file: $ locate error_log If you find it for example in: /var/log/apache/error_log, then you should print the last 6 lines of the file: $ tail -6 /var/log/apache/error_log Then copy these files and paste them here. It might be very easy to solve.

An entity is your interpretation of something. If your interpretation is not fomulated correctly, then what you are percieving as a thing is actually nothing. We call it a thing because this is what we first would think is, but that's not actually what it is. After proving that it cannot exist, then it must be considered as nothing. Now, don't confuse the definition of the word 'nothing' as it would be written, seen, or even percieved, with a non-existing thing. Note: if your interpretation of something is absolutely correct, then that is a fact. A basic set of facts must exist in the first place for us to be able to conclude new ones. If we interpret our observations, then we are taking our observations as facts. BTW, it is too hard to write philosophy in English when it is a second language! I wish I could write more, but I know I will be misunderstood.

1st pre-clinical year. Studying Anatomy, Physiology, Biochemistry and Community Medicine.

Hmmm. That's not much of a help. Try to visit the page, and when error 500 appears, get the last 5 lines in your error log. You know how to access your error log? It is basicly a file called error_log. If you need more specific information or commands I'll try my best.

You will find more information here: http://www.indstate.edu/thcme/mwking/rna.html#clinical Look for the calcitonin example.

Can you please provide more information about the error message you are getting? Also, what kind of configuration you have on the server?

Well, we are only transplanting a pigs heart. For an immune responce to occur, he will need to produce a lot of immune cells, which are not present in large quantities in its heart. That might be the answer. I haven't taken any immune course yet.

Well, an organ from a brother could cause a rejection What they are trying to do is to remove parts of the organ that trigger rejection in the donor. This means a lot of experiments, which is not ethical to do on humans. It is more a matter of what animal is easier to remove rejection factors from and which animal has the best organs for human needs.

Gene therapy is now done in different ways. The easiest one is by taking some tissue from the patient, aplying gene replacement techniques and letting it grow back into the patients body. You can, for example, take bone marrow from a person with sickle-cell-anemia, correct the gene, then grow it back into his marrow. This will be just like a transplant but with no rejection problems. Another way is by adding a DNA segment to all the somatic cells of an individual. This can be done using retroviruses. Retroviruses are viruses that contain RNA as their genetic material. When they enter a host cell, they use their RNA material to create DNA genes and insert them into the genome of the host cell. If you put the gene you want as RNA in such a virus, then you can use that virus to spread the gene to all the somatic cells. This technique is already being used experimentally, but is currently causing trouble (Leukemia). This technique, of course, is limited to inserting genes. It can be used to produce a protein that is not sufficiently available or to stop the production of a specific protein that is causing trouble, but it cannot be used to correct large scale problems, like a trisomy (e.g.: Dawn syndrome). I'm not sure what is the problem in using this at the embryonic level. It actually seems easier to achieve. Still, we must be very sure about the precision of our techniques. Embryonic cells must go through a lot of divisions and differentiation steps, so a tiny problem in there could actually scale to cause large problems in later development of the embryo.

Besides that, pigmentation only protects you from visible light spectrum, not from UV radiation.

The question was about a single mRNA message coding for different proteins, that is why I mentioned the thing in prokaryotes. In case you mean why it must be studied, then the answer is that it is important for recombinant DNA technology, utilizing bacteria to produce a specific protein we need. There is also another point regarding introns and exons. Some mRNA messages are spliced differently in different kinds of tissues, yielding two distinct proteins based on the tissue.

Hi aman, pleased to meet you too. The major problem in such a transplant would be restoring the original connections. If you could do that, you will be probably able to restore the problems. What makes any part of the brain disticnt and unique is its connections. When you call a certain part of the brain a "cardiovascular center", for example, you mean that it is where specific connections are made from and two specific parts of the brain and viscera, and these connections are what determines the properties of that center. So if you want to transplant any part of the brain, you must make sure that each and every nerve fiber is connected in the right manner and the right place. Any small change means that you'll get bizarre effect. Imagine how can you survice if when you try to send a nerve impulse to your hand to move it, it will be sent to the heart increasing its rate! Besides, if you cut nerve fibers in the middle, you are actually cutting neurons' axons. In order for the axons to come back together, they must be really accuratly aligned. When you have a lot of cut axonds on two sides, how would you make each axon find its other part and connect with it correctly? Now, regarding stem cells, you must first understand that connections between the brain parts and the viscera are made because of the varying rates of development of the different parts of the body and the effect that each part creates on the other parts. It is like a very advanced unpacking mechanism. The simplist part to understand is how each nerve fiber finds its organ? Actually, it doesn't. Nerve fibers are already there in the organs in the first place, and as the embryo (or the born child) grows in size, the organs start to move away in different directions, each dragging with it its nerve fibers. So nerve cells do not contain specific directions that tech them how to form the different connections, eliminating the possibility of using stem cells. Now think about the kidney. It is a highly modularized organ. It has all its mass of cells in a single specific place, with a specific entrance and exit for blood and an exit for urine. You can easily remove a kidney from one person and put it in another and all you have to do is to make the three connections (artery, vein, ureter). Of course, i'm being very general. Kidney transplats are not something that easy to do successfully. The same thing for using stem cells to replace the kidney tissue. It has a specific place and a very general organization, so if you can just put some cells in that place they will function without so much need for any special arrangement.

That's quite true. People with albinism don't have any melanin at all. Even normal white people have melanin, but its effect is only noticeable when they stay for a long time in the sun, when they get darker.

Actually, all parts of the brain need their original connections. These connections are vital for the internal regulation and functioning of the organs (e.g.: regulating heart beat). The cells of the nervous tissue are unique in their structure. They are very long with a cell body in one part of the brain and an ending in another part or even outside the brain and spinal cord. You can't just cut a part that contains an arbitrary number of cells and replace it with others. Each cell is unique in the brain because of it's path and connections.

This can never be used to fix problems in nerve cells (neurons), because their wearing off has nothing to do with telomers and proliferation. It might, however, help correcting neurological disorders caused by the limited proliferation of glial cells.

On a side note: albinism is caused by a defect in the enzyme tyrosinase responsible for converting tyrosine into melanin.

Keywords: polycistronic RNA, multi-cistronic RNA, operons

I'm not sure if that is what you mean, but in prokaryotes, there are no introns or exons. But they contain specific sequences that mark a seperator between two different proteins. So for a single gene, transcribed in a single mRNA message, two proteins are produced.