Introduction to Cell Signaling

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.

So now that we know from our last lesson video that cell signaling requires a minimum of two key components the like and or the signaling molecule and the receptor in this video, we're going to focus on the three steps of cell signaling. And so cells received external signals in a Siris of three steps that we have number down below number one, number two and number three. And so the very first step of cell signaling is going to be reception or, in other words, like and binding. And so in this first step of reception, the ligand or the signaling molecule is going to bind to a very specific receptor, causing the receptor to change its confirmation or to change its shape. And so if we take a look at our image down below, which will notices, um, here, this membrane represents the cells plasma membrane that's separating the outside of the cell from the inside of the cell. And so over here on the left hand side, what we have is the outside of the cell or the extra cellular fluid, and over here on the right hand side and the yellow background, what we have is the inside of the cell or the cytoplasm, and so notice that embedded here within the membrane is a receptor and the signaling molecule or the like, and is here in red. And so in the very first step of cell signaling, which is again reception, what happens is the lie. Gand, or the signaling molecule here is going to bind to its receptor. Like what we see here, the ligand is now bound to the receptor, and when the ligand binds to the receptor, it's going to cause a confirmation will change in the receptor, which will lead to step number two over here. And so in step to what we have is trans duck shin. So after the lie again binds to the receptor and causes a confirmation, all change in the receptor. This is going to lead to a pathway of interactions in the cell that ultimately is going to trans deuce as implied by transaction or, in other words, convert transducer or convert the signal to change to a change within the cell. And so, in the process of transaction, there's really just gonna be a Siris of interactions, and this Siris of interactions is ultimately going to convert that external signal or that external lie game, uh, into a change within the cell. So let's take a look at it. Step number two down below right here. And so notice. Step Number two is trans deduction. And so, with transaction, there's a Siris of events. Notice that we have a B and C here within step number two, and so in transaction. What happens is the confirmation I'll change within the receptor from step number one is going to lead to a Siris of events where some molecule is going to become activated, which could lead to the activation of another molecule, which could lead to the activation of another molecule and so on. And ultimately, the trans duck sh in step here is going to vary significantly between different pathways. But ultimately, with transaction, there's gonna be a Siris of events, and at the end of transaction it leads to the last step, which is the cellular response. And so that is our step number three of cell signaling. And so the cellular response is going to be the end result of the cell signaling pathway that is going to end up causing a physical or chemical change in response to the extra cellular lie again that originated. And so the signaling molecule or the lie again and ultimately is going to be triggering this cellular response. And so the cell responses generated, uh, in response to the extra cellular signaling molecule or the like. And and so really, this here concludes our introduction to the three steps of cell signaling. And again, as we move forward in our course, we'll be able to talk more and more about cell signaling, so I'll see you all in our next video.