why does a nerve cell and a liver cell in the same organism contain different combinations of proteins.?

Question

why do different cells have different protiens? what is the difference.

Answer 1

cells contain the same genetic content. however, our genes express differently to serve different purpose of the cells in different part of our body. some cells needs protein A more, therefore, protein A expressed more. some cells need protein B more, therefore it expressed protein B. nerve cells function is different from liver cell, therefore, there is not necessary to express insulin. but no matter what, the DNA in both cells are the same.

Answer 2

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RE:
why does a nerve cell and a liver cell in the same organism contain different combinations of proteins.?
why do different cells have different protiens? what is the difference.

Answer 3

Because cells communicate with each other by cell-cell adhesions, and through chemical signaling by ligands and receptors. These factors tightly regulate what proteins a cell and its neighbors synthesize.

As far as how differentiation STARTS. Well embryology is very complicated, but it has to do with diffusion of transciptional regulators, HOMEOBOX genes and SONIC HEDGEHOG genes seem to be the most important.

LOL, to the asker, please ignore the 2nd responder, as he or she does not have a clue about embryogenesis or morphogenesis. Specialization of cells is more understood than you or he/she would think.

So, you understand that every organism starts off as one cell, but each with UNIQUE DNA. And by nature, programmed into DNA is a regulated cell cycle, and when a cell reaches a certain point, it will divide mitotically, from a single celled zygote, to 2 cells, and then to 4, and then to 8, and then to 16, etc.

When the embryo reaches a certain number of cells, it will be in the shape of a ball. Some will be in the inside, some will be toward the outside. The cells synthesize and release proteins called transcription factors that control what genes get transcribed and thus what proteins get made. Cells toward the middle are more likely to be exposed to more of these transciption factors than cells toward the outside, by simple diffusion, logically. I gave you 2 examples of transcription factors (sonic hedgehog, homeobox), but there are many.

Cells also can talk to each other through cell-cell adhesions, so through these 2 mechanisms (far more complicated than I explain to you here), cells differentiate.

Experiments have been done to fruit flies where biologists have been able to grow limbs where eyes should be, simply by changing DNA!

Answer 4

Because of the spiritual blue print. Science cannot explain how a single cell in the womb change into many types.

Answer 5

it is because these different cells have different functions and thus require different proteins to work effectively

Answer 6

Second one is not clear.. Guess u r back after a long time.. R E B E L? I remember u..