Hello students. This is a short introduction into the cell. So we're we've already covered the chemical level of organization and now we're going to start with the cellular functions. And so it's important to understand what are the functions of the cell and then we can look at how the cell carries out these functions. There is a brief review on the organels of the cell at the end of the slides that is for you to review on your own. I'm not going to go over those that that's um you should have had that in anatomy and bio5. So if you are struggling with that or you um need to review that go back and you can go through those slides on your own. We're going to focus on the the functions of the cell. And so we'll go ahead and get started on that. So what are cell functions? And we can go back to the functions of life. Cells carry out metabolism. They carry out growth. They carry out transport. They transport across the membrane. They transport within the cell themselves. You've they've got to move things between organels and across the cytoplasm. They communicate. um there's communication within the cell and there's communication with other cells outside of themselves. Um and of course we talked about reproduction. So they grow, they increase in size and they divide and we'll talk about that in this lecture in the in this unit as well. And when we talk about cell metabolism, they do all of the reactions that we talked about in previous lectures. They do synthesis reactions. So anabolic reactions, putting things together, building things up, making macroolelecules. So proteins, lipids, carbs, DNA, they do catabolic reactions, breaking things down, um, breaking things apart, reusing it, um, breaking things down for energy. Oxidation reduction reactions. We're going to talk about that a lot next week when we get into cellular respiration. Um, that's really important. And then that's the energy transfer with electrons. So we'll talk about these throughout our course. It's important that you understand that these things are going on within all the cells in your body. Other things that the cells do transport. Again, transport occurs across membranes. We're going to talk about that in other um lectures in this chapter. And communication. How did the cells communicate between um other cells that are nearby and then how do they communicate far away? And so there's a whole chapters on this when we talk about the endocrine system and the nervous system. These are ways that cells are able to communicate um with cells that are far away or even nearby. So chemical and electrical signals. And then of course reproduction. We're going to talk about cell division. cell division for growth and repair, but then also cell division for repro um sexual reproduction as in you know creating a whole new organism. We'll talk about that later on in our semester at the very end when we talk about meiosis. In this unit, we'll talk about mitosis which is the cell division for repair and growth. And so when we when you think of the cells and we're we're going to start with the cellular functions and then we're going to um talk about tissues later and how the tissues work together to to for organs to do their functions. um keep thinking about the cellular processes that we're learning about in these chapters and how those things are working together to maintain homeostasis and to carry out these physiological functions that you're learning about. And so here you can see an example of a cell carrying out mitosis. Here it appears that we've got a cell looks to be in metaphase because the chromosomes are lining up on the equator. Um maybe they're being pulled apart here. It's hard to tell if they're if they're separated, but you can clearly see that you've got the motatic spindles forming and you've got chromosomes lining up on the equator there. And so you can see the cell in the process of cell division. And so it's important to understand these processes to understand what's normal and then also understand what happens when things are abnormal so we can figure out how to fix that. So when we talk about cell structure um how how does a cell carry out these processes we have to understand cell structure. We're not going to get into all the different organels um other than we will spend a lot of time on the plasma membrane when it comes to structure because we're going to talk about transport. Um but the cell structure is pretty pretty pretty standard when it comes to basic components. We have a cell membrane that separates the external environment and the internal environment. We have cytoplasm which is the the fluid inside the cell. So the inner um this is the intracellular fluid and within that cytoplasm you have organels um and the cytokeleton which is the the the structure of the cell which determines the shape of the cell and this will vary depending on on the type of cell that you have and this can change based on what the cell is doing. Um the organels carry out cell functions they can be membrane bound or non-membrane bound. An example of this would be um a membrane bound organel would be Golgi apparatus or the smoothie R or the ruffy R or the nucleus and the non-membrane bound organels would be um ribosomes and then of course we have the nucleus which is the control center basically for the the cell this the where the DNA is housed and this is where the all the genetic material is and we're going to talk about that a lot when we get to um mitosis and cell division and um protein synthesis. So that will be important. So we have the nucleus, the center and that's membrane bound as well. the cytoplasm which is the fluid with the organels and the cytokeleton within that and then the plasma membrane that that separates the external environment the extracellular fluid outside the cell and the in intracellular fluid inside the cell. And so again cytool contains intracellular fluid. It has dissolved solutes like um electrolytes, sodium, potassium, um glucose, amino acids. Um it may have storage molecules like vacules, lizoomes, um there can be proteins in there. And then of course this is going to be a site for chemical reactions. We'll talk about next week. This is where glycolysis occurs. So um the anorobic portion of energy production the breakdown of glucose this is where that is occurring. So many chemical reactions are occurring in this in the cytool. Um organels these are these are specific compartments within the cell or specific um structures that carry out functions of the cell. So specialized regions and these are within the cytool. The number of organels and type of organels that are in each cell vary depending on cell functions. So um a liver cell might have more um lizoomes to break things down because it is it is responsible for detox whereas a muscle cell is going to have lots of mitochondria because it needs energy for um muscle contraction and it's going to have a lot of m um myophibbrals. So they're going to there's going to be different variations on the number and types of organels within the cytool depending on the cells that we have and their functions. And then the cytokeleton, this is going to be the the microtubules and the microfilaments and the intermediate tubules. And these provide the shape and the structure and the um tracks so to speak for things to move and tr be transported throughout the cell. And this can be dynamic. This can change um based on what's happening within the cell. So the cell can can change the cytokeleton and direct pathways to move things based on what's happening. And then of course the nucleus, we talked about this. This is membrane bound. Um it's spherical. There are pores within the within the nuclear envelope that allow for movement between the nucleus and the cytoplasm. And this contains the DNA. And so this is where um transcription is going to occur. This is where we make our messenger RNA. And we'll talk about that later. And um this is where the DNA is housed. So it's protected in the nucleus in this location and it doesn't leave this this location. And of course we talked about cell size and diversity. Cells vary depending on their functions. So cells can be are specialized for their their role in whatever they are doing. And this is very important to understand. They all have the same DNA. They all have the same genetic component. But certain genes are turned on to allow them to carry out their functions. So they're using specific genes to to carry out this specialization and do their jobs. And so we'll talk about that in our protein synthesis lecture. So if you're interested in that, go to the protein synthesis lecture and you can see more about that and how we actually carry out and express those genes and cell cell functions. Our next lecture is going to be on the plasma membrane structure and this is going to be important in keeping our outside separate from the inside. So I hope to see you there.