Human beings make for great scientists, but crummy biological test subjects. Think about it for a minute—if you were a researcher, how would you study an organism that is genetically diverse and takes decades to mature? These are only a couple of the many challenges that biologists face when studying human health and disease.
General Biology encompasses all aspects of the life sciences. We will explore the world around us with a very broad scope, investigating everything from the microbes that live within us to the ecosystems we ourselves inhabit. All of life is subject to the same natural forces. We will describe the myriad of different ways that life responds to these forces, the progress being made in expanding our understanding through biological research, and how this insight is being applied in the field and in the lab.
More than 200 million people in the world are infected by the parasitic worms
Scientists have known for decades that cells readily communicate with each other. To send signals close by, a communicative cell can nestle up to a neighbor that has the lock into which its key fits (yes that is a euphemism - a euphemism for [ligand-receptor binding](http://www.mindcreators.com/developmentalsim/ReceptorsLigands.htm). To talk to other cells they aren't directly touching, cells can release substances such as hormones). These substances enter the circulatory system and eventually are sensed by other groups of cells that can respond to that specific signal. We pretty much thought those were the only two broad ways that cells could talk to each other by directly touching or by releasing signaling molecules. However, in the 80s, a group of scientists first described tiny spheres, or vesicles, inside cells in a laboratory . They noticed that these vesicles were eventually expelled into the cell...
The space inside your cells is quite crowded and many cellular contents are more liquid than solid. How do our cells make sense of all the different interrelated liquid parts that make them up? Phase separation. Phase separation describes the separation of liquids, gasses, and solids (different phases of matter) but it can also refer to the tendency of some liquids to stay separate, like oil and vinegar in a vinaigrette. Liquids like these have inherent chemical differences that make the molecules of one liquid repulsive toward molecules of another liquid but attracted to themselves. Therefore, liquids in this situation like to segregate into separate parts that we can also call phases. The different liquid phases in a mixture can distribute as layers or as droplets of one liquid within another. Cells can concentrate different proteins and nucleic acids into temporary phase-separated liquid droplets that can perform specific tasks to help cells respond to the world around them.