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Current time:0:00Total duration:8:42

Video transcript

let's give ourselves an overview er synthesis of all that we've learned about plant and animal cells and what I have over here on the left this is supposed to be indicative of an animal cell animal cell and what I have on the right this should be indicative of a plant cell plant cell so let's start with the what's outside of the cell so we see in both of them we see the extracellular matrix you see on this animal or outside of this animal cell you see all these collagen fibers and everything else and all these fibers that are holding these cells into place and allow the cells to relate to each other and actually the depending on what's inside of it can even help signal different things to the cells so this is an extra cellular matrix now when we think about the extracellular matrix for our plant cell we also think about the some of the components that are involved in the actual cell wall and so the cell wall is a key difference between plant and animal cells so cell the cell wall is going to be in a plant cell animal cells don't have cell walls now if we go one layer deeper we get to the plasma membrane the cellular membrane and we see that that is common to both the animal cell is going to have a plasma membrane and the and the plant cell is going to have a plasma membrane and they actually can both have tunnels from neighboring cells or tunnels between neighboring cells we studied that in the cell wall video for plant cells we saw these things right over here called plasmodesmata and we actually see a complete one over here because I start to draw a little bit of an adjacent cell plasma plasmodesmata does mater and in animal cells the analog R gap junctions which are still tunnels between adjacent cells so gap gap junctions now plasmodesmata are much more common to a much wider category of plant cells than gap junctions but gap junctions can be very relevant in certain types of animal cells in particular things like heart cells where because of gap junctions between adjacent cells electrical signals can move through the tissue and let adjacent cells know hey it's time to contract in the right way so this is still very crucial for certain types of animal cells so now let's go a little layer even deeper actually before I do that I want to re-emphasize this and I do this in almost every video all of these membranes that we draw either the outer cellular membrane or the membranes of these organelles these are all lipid bilayers or phospholipid bilayers so if I were to zoom in right over there on this yellow place right over there it looks just like a line but it really is it really is a they really are these phospholipid these phospholipid bilayers that have these hydrophilic heads that point outwards and these hydrophobic tails that pleat inwards and it keeps going I want to make that very clear these lipid bilayers all of these membranes that I draw are lipid bilayers but let's keep on going so as we go now into the cell we see that both of these cells have cytoskeletons I have cytoskeletons so you have your micro filaments right over here microfilaments right over here and I'm not giving full justice to the complexity just because we want to be able to have a fairly simple looking diagram you have your micro tubules micro tubules you might have intermediate filaments and we talked about all of those things in other videos but now let's dig a little bit a little bit deeper so in the animal cells I have these centrosomes and they are key for organizing the micro tubules and we're going to see them a lot when we talk about mitosis we don't see them in plant cells they actually figure out ways other ways to organize their microtubules especially well in general and especially even when we're thinking about something like mitosis but let's see what other differences are here well one big thing that you might notice is this big blue balloon egg looking thing and it doesn't contain these green things it's really just behind these green things and this is these tend to be associated with plant and fungal cells this is a central vacuole central vacuole and a central vacuole can store fluid it can store enzymes it can be viewed as a place for waste and it actually turns out that even though they're common to plants that depending on which plants which cells they can have very different roles and I want to emphasize this to you and I do this in other videos we keep seeing all these organelles and we can draw pictures we can draw diagrams of them and we think we know what most of their functions are but almost all of these organelles and all of actually the cell is area whether it's an area of active research you know in the decades to come we're going to find more and more things that these different organelles do in ways that they signal to each other and interact with each other and behave in different circumstances so we're starting to understand what's there and have an idea of what they do but in the decades to come we're going to learn much much much more about the different structures and functions of a cell but as I mentioned this is central vacuole big it's large it can help provide structural support for the cell can help store things and the best analog on the animal cells some animal cells actually can have a vacuole not not all of them but the best analog is the lysosome so this right over just in the orange color this right over here is a lysosome lysosome lysosome and a lysosome could be viewed as the waste disposal of an animal cell where it's going to have a bunch of of enzymes in it so that things can kind of go in there and get broken up it has a low relatively low pH of a more acidic pH so that things can be broken up in different ways and then there their individual pieces can be recycled and since we're in this category if places where things go to get maybe broken down or catabolized or metabolized in certain ways it's also worth talking about the peroxisomes peroxisomes pair roc citizens so the peroxisomes we actually see in both of them and they're named that way because when they were first studied they said hey there's something going on here where the there's some oxidation reactions going on here it seems like the final byproduct seems to be hydrogen peroxide and so that's why they were named peroxisomes and we're still understanding exactly all of the things that they do but we know that they're important for for for cutting up long-chain fatty acids so that they can be more usable by other parts of the cells but they also have other roles and all of their all of their mechanisms are still not still not fully understood now going back to differences between the plant cell and the animal cell a key difference is going to be these characters right over here these are chloroplasts this is where photosynthesis takes place and clearly we're going to show it in the plant cell this is how they take they are able to create they're able to create essentially a fluid or or I guess you could say fix carbon based on light energy so let me see chloroplast chloro chloroplast right over there we do not see that in the animal cell now when we're talking about energy we talk about the ATP factories of cells and we find this in both of these cells and that of course are the mitochondria and we see the mitochondria in both of the cells and then the other things we also see a lot of common things we see a Golgi we see the Golgi apparatus in that cell we see Golgi apparatus in that cell and that's where we package proteins for use either within the cell or outside of the cell we have the endoplasmic reticulum we have the rough endoplasmic reticulum that has ribosomes bound to the membrane and we have the smooth where you don't have the ribosomes and this is where a lot of proteins get manufactured but include and all but even lipids also can get manufactured then you have of course the nuclear membrane actually this is the inner nuclear membrane right over here the outer nuclear membrane is contiguous with the endoplasmic reticulum but you see that in both of these cells and inside of course you have the DNA it's in chromatin form and then you have this kind of extra dense root area that shows up in microscopes which we call the nucleolus which is associated which is associated with ribosomal with ribosome formations and ribosomal RNA and of course you also have free ribosomes free you also have free ribosomes so this is a very high-level overview of cells eukaryotic cells I should say but hopefully it also starts to show you some of the key distinctions between animal and plant cells
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