in this video, we're going to begin our introduction to sell signaling Now. Cell signaling is really just defined as the ability for all cells to produce, receive and respond to external signals or conditions in the environment. And so ultimately, cell signaling is going to allow for effective cellular communication, allowing for a cell to communicate with neighboring cells in its vicinity, but also communicate with distant cells that air further away as well. Now as we move forward in our course, we're going to talk a lot mawr about cellular communication and cell signaling. But what's important to note here is that cell signaling is going to require a minimum of two key components that we have number down below number one and number two. And so the very first key component of cell signaling is going to be the ligand itself. And so the lie Gand is defined as a small signaling molecule that is going to bind and form a complex with another bio molecule or a receptor, and this leads us to our second key component of cell signaling. And that is the receptor itself. And so the receptor is a bio molecule, typically a protein that is going to change, shape or change confirmation upon ligand binding. And so when the like and or the small signaling molecule binds to the receptor, it's going to cause a confirmation. All change or change in shape of the receptor. And this confirmation will change is going to lead to a Siris of events within the cell, ultimately ending with a cellular response. And so let's take a look at our image down below to clear some of this up. And so notice that in this image we have two cells. We have this cell over here on the left hand side, and we have this cell over here on the right hand side. Now, notice that this cell over here on the left hand side, is producing or generating this yellow circle here that we're calling the lie Gand and again like and is a small signaling molecule. And so because this cell here is producing the like and this cell over here on the left is going to be the signaling. So that is generating the signal or the like. And and so this lie again that's produced by the signaling cell can diffuse over towards this other cell over here, which notice contains a receptor embedded in its cell membrane. And this receptor again is typically going to be a protein. And when the lie Gand actually comes and binds to the receptor that is going to cause a confirmation Allchin change or a change in the shape of the receptor itself. And this confirmation I'll change in the receptor is going to lead to a Siris of events that's ultimately going to lead to the cellular response. And so ultimately, this cell over here that has the receptor is going to be called the target cell because this is the cell that generates the cell response. And so what we're seeing here in this image is that this cell over here, the target cell is generating a cellular response to the signal or the Lagan created by the signaling cell. And so what's happening is this signaling sell over here is able to effectively communicate with this target cell over here, okay. And so there are many different types of signaling pathways that lead to different types of cellular responses, and there are also many different types of Liggins or many different types of signaling molecules. And over here on the left hand side, we have this little table showing you some of the different types of Liggins, or signaling molecules that can lead to a cell response. And so the lie again or signaling molecule could be in amino acid. Ah, protein lipids or hormones, which we'll get to talk more about moving forward in our course nucleotides, dissolved gasses and neuro transmitters, which will also get to talk more about moving forward in our course. And this is just a small subset of the possibilities, that of Liggins or signaling molecules. And so this here concludes our brief introduction to sell, signaling. And again we'll be able to talk Mawr and Maura about cell signaling as we move forward in our course, so I'll see you all in our next video.