Specialization and Differentiation
Mar 13, Cell specialization, also known as cell differentiation, is the process by which generic cells change into specific cells meant to do certain tasks. Cell specialization refers to the functions that certain cells have, such as red blood cells are specialized to carry oxygen. Cell differentiation is. Cell Specialization and Differentiation. Cell Specialization. Specialized cells differ in structure and function. Adaptation for certain cell job. Cell Specialization.
Having different proteins around, that changes the way our cells look and it changes the way our cells act so it gives our cells really different abilities. What I mean with the exception of the red blood cells which lack nucleii, every single somatic cell in your body contains the exact same DNA.
Yet this muscle cell here, right, it looks and it acts differently to this neuron here. That's because they're each reading different books in our DNA library.
Cellular specialization (differentiation) (video) | Khan Academy
They're using different genes to make their proteins. Just a bit of terminology here, when a cell is actively using certain genes, it's said to be expressing those genes. A gene being expressed is said to be turned on, and one not being expressed is turned off, so just keep that in mind.
Why am I telling you all of this? Because in the end it all relates to how our stem cells all the way up here end up differentiating into our specialized cells down here.
The bottom line is in order to differentiate to, for example, specialize into our muscle cell here, this stem cell up here turned on its muscle cell genes.
Here's its DNA and I'm highlighting its muscle cell genes that it turned on right now. It also turned off some other genes.
By turning on its muscle cell genes, now proteins get made within the cell that changes how the cell looks. See now it's a bit elongated, right, this muscle cell here.
It also changes its functions.
Now our muscle cell has contractile proteins in it to help it be a nice useful muscle cell to help us move around, right? Now our neuron here, our stem cell turned on its become-a-neuron genes here, right? It turned off some other ones, and then the cell started producing all the proteins it needed to turn into a neuron.
Like the proteins that would make it elongate like this and grow out these little spiky things up here called dendrites, okay? Let me also say that remember our stem cell up here was pluripotent.
It could turn into any of our somatic adult body cells. But once it's specialized into these mature cell types, these can't go on to differentiate into other cells. They actually can't de-differentiate either. They can't go backwards up to stem cells naturally, at least in us humans. So these cells stick around to form our bodies. By now you must be wondering what determines what genes in the given cell are turned on or off?
In other words, how the heck does this cell know it's time to specialize into a different cell type? It turns out that cells decide what they're going to grow up to be based on cues they get. These cues can be from their internal environment or their cues can come from their external environment, their outside environment. Let me just show you two major ways this can happen here, these cues.
In the development of lots of different organisms, us humans included, we start out with one cell, right, the zygote.
Our zygote has these little proteins called transcription factors floating around in its cytoplasm. Also the precursors of these transcription factors are there too, little bits of MRNA. Two things to note. First, transcription factors will activate certain genes and turn them on.
That's what transcription factors do. Thus single-cell organisms must maintain a wide range of complex behavior in order to respond to the wide range of possible environmental conditions they may encounter.
In contrast, cells in multicellular organisms can rely on the whole organism adapting to changing conditions via a multicellular response. So the individual cells can dispense with the rarely used functions. Social insects demonstrate the same sort of tradeoff: That sort of specialization is known as differentiation. If we compare a mammalian neuron with a lymphocyte, for example, the differences are so extreme that it is difficult to imagine that the two cells contain the same genome.
The cells in which this occurs are called neoplastic i. Neoplastic cells are not just abnormal, they form tumors. Tumors may be benign, but are often a hallmark of cancer. Specialization is deeply intertwined with the other three multicellular organizing principles in part because the orchestration of many kinds of simple elements requires more careful messaging mechanisms and a different sort of communication strategy called stigmergy.
Cellular specialization (differentiation)
Multicellular specialization at the cellular level is possible because the environment faced by a cell in a multicellular organism is quite different from and more benign than that faced by a single-cell organism in its natural environment. Metazoan cells live in a cooperative, nearly homeostatic environment protected and nourished by the whole organism. In contrast, a single-cell organism must be prepared to deal with all sorts of unfavorable circumstances such as predators, changing abundance of nutrients, and toxic chemicals.
That flexibility requires each cell to support a large complex repertoire of behavior. For individual cells, one obvious cost is energy consumption; the maintenance of all the unnecessary cellular machinery is not free. Since each specialized Metazoan cell uses only a small fraction of the total genome, its energy costs can be dramatically reduced.What Is The Difference Between Cell Differentiation And Specialization?
But also cell specialization induces very different and incompatible cellular biochemistry, shape, and function.