Standard Cellular Signaling Pathway

Standard Cellular Signaling Pathway

Sunday, September 16, 2007

The NK Linked Lecture Series: The Uniqueness of the Human Brain

An outstanding presentation given by Dr. V.S. Ramachandran. This presentation focuses on neuronal cross-wiring resulting in phenomena such as phantom limbs and synesthesia. This presentation is part of a lecture series by IBM.


Wednesday, September 12, 2007

A Protein's Manifest Destiny

Do human beings have free will? Or are we subject to some form of manifest destiny, that our calling is pre-ordained? Many people have invested much thought and effort to questions relating to these themes. Due to the nature of such questions and the way that our society works, perhaps there will never be a unified consensual agreement to the answer of these questions.

If we look, an analogous situation is presented in cells. Proteins are subject to diffusion and brownian motion, the molecular equivalent of free will albeit mindless free will. They diffuse haphazardly, randomly; such could be said for an individual's life. A protein could interact with other proteins, aggregating for a while, moving on down a chemical or electrical gradient. But they are not completely free to wander around the cell aimlessly. Within the protein itself exists a manifest destiny, it's signal sequence. Many secretory proteins have an initial sequence that will ultimately be cleaved by a peptidase, but nonetheless this sequence acts as a address on an envelope, labeling the protein. This label determines where it ends up, free floating in the cytosol, packaged into a secretory vesicle, or firmly planted into a membrane.

Maybe the determinants among us can take this as an argument that bolsters their theory but it necessarily isn't. There are exceptions to this rule, many proteins are not labeled with a signal sequence. Once translated they are free to wander about as they please, until they find a suitable partner to interact with or until they age, becoming less functional and eventually inactive.

Free will or determinism. Even a molecular level, we cannot say which is the case.