hi everybody and welcome back to miss Angler's biology class I am Miss angler in today's video we are going to be looking at an introduction to transport in Plants now if you haven't watched my video on plant tissues it's really important to go watch that first because I'm going to be using a lot of names of different tissues you're going to need to know what they are and what they do before we can move on to Transportation now if you are in grade 10 and you're watching this video and you want the upper Edge on your studies and there's just so much to learn in grade 10 compared to grade 8 and N then you should get your hands on my cheat sheet study guide for grade 10 it's available on my website Miss anger. co. Za it is the easiest way to get a distinction so let's dive into the video now and we need to begin first of all with some adaptations of roots and where exactly does our um Journey begin so what we have over here is a cross-section of a root a little tip of the root all the way at the very end and you may be familiar with some of these um tissues on the inside of the root like xylm which is of course the tissue that transports water we've got Flo which is the tissue that transports nutrients like sugars and then we have something called cambium which is the um tissue that grows and makes you know roots and Stems thicker and wider but what we are focusing on today is these teeny tiny little outgrowths and now these are root hairs but specifically everybody I want you to know that these are root hair cells and this is really important because they are microscopic okay they're not macroscopic you can't see these particular ones with the naked eye you can see root hairs like the really small ones but the ones that we are talking about today in this lesson are root hair cells and they are microscopic so we've zoomed in on them over here and you can see them stacked on the outside with their like elongated um extensions and I want you to imagine that there's like soil particles in and around these long hairs that are sticking out now we need to go further and we need to look at the adaptations that these root hair cells have starting first and foremost we need to look at the outer layer of our root cell first of all it lacks which means it doesn't have a cuticle now you should know what a cuticle is but if you don't a cuticle is a waxy outer layer that is waterproof now let's problem solve here everybody if the roots are there to absorb water why would you put a waterproof layer on it you wouldn't and so this particular epidermal cell the root hair cell doesn't have a cuticle which is important and we must note that it is an adaptation another thing about our rotair cells and their adaptations is these finger like projections over here that come out of the cell and basically they increase the surface area now anytime you increase any surface area what you are trying to do is you are trying to make the cell more efficient and in this case we want to make it more efficient in absorbing water there's a bigger surface area therefore more water can be absorbed the next adaptation is the fact that this long elongated part of the root hair is penetrating the soil particles in other words if this wasn't here like let's say we cut this off over here and our cell was just Square we wouldn't be able to reach all of the water that might be in between these particles so we would have to wait for osmosis and for evaporation before the water would be able to get to our cells instead we have these extra outgrowths that come out of the cell and that increases the surface area but also reaches into the soil for water now the final thing and the final adaptation that we do have in our root hair cells is going to be this enormous vacu which we can't miss it is basically taking up almost the entire cell and it has a large vacu for the simple reason of what a vacu does large vacu are going to stor store excuse me large amounts of water all right now how that works and the chemistry behind that I'm also going to elaborate because it must be a large vacu so it can create a water potential which basically means it creates a mechanism to allow water to passively move in and we need to do that with some chemistry that we've learned earlier in the year via osmosis now one thing that is missing from this diagram that is also an adaptation with root hair cells is they have got a lot of mitochondria so imagine I'm just going to draw in a couple of mitochondria into this picture but they've got a lot of mitochondria and the reason for having so many mitochondria is we need a lot of energy for something called active transport you may remember this again from learning this um in our section on cells and how you move substances across membranes active transport needs energy and who makes energy mitochondria now let's get into creating the water potential in other words creating the mechanism that pulls water into a plant and this is very technical if you haven't watched um my video on osmosis and moving water across membranes I suggest you go watch it now I'm going to link it above for you to watch but there's a couple of words that I want you to keep um in mind when we talk about creating a water potential we are going to use words like a high and I use a symbol by the way water potential that's the symbol for water potential and a low water potential what do those words mean if I were to break them down further if it is a high water potential what it means is there is a lot of water so a high amount of water but when it comes to salts or ions I'm going to rather use the word ion because that's more correct an ion is like a salt everybody it's like having a dissolved like sodium or potassium the ions are low and likewise it's now just the opposite so a low water potential the water is low in amount and the ions are high so now how do we make a water potential so we've got some very simple physics that we must remember that we've learned the beginning of the year when we want to move water via osmosis we want to move from a high water potential to a low water potential and that requires no energy and no effort but here's the thing in order for that to always happen you have to create a consistent flow flow of water from high to low and unfortunately plants are not always in a state of being well watered sometimes they live in very arid places and they really rely on getting as much water out of the soil as possible so this is where active transport comes in active transport if we forgotten is when you are going to take water from a low well not a water a substance from low to high now that requires a lot of energy when you want to move from a low to a high and that's where those mitochondria come in and I'm going to explain that now on what the mitochondria are actually doing so if you have a look at our little root hair cell diagram you will notice that there are some particles moving into our root here so what I want you to imagine is there is a high water potential on the outside of our root here and there is is a low water potential inside and let's say we focused in on these purple particles they are our water particles that are going to be moving into our root hair they're going to be stored inside the vacu which is this big empty white space that is the vacu now here's the thing if you move particles from a high to a low for long enough doesn't the inside now become High and the outside low very good question the answer is no because what's happening is as water is entering into our root hair cell it's actually going on a journey deeper into the root which we're also going to cover today as well and there's a constant change over maintaining gradient or in this case we are going to be maintaining the water potential which means that we want to be moving from a high to a low water potential now there is one more thing that plants and particularly their root hair cells can do and that is they can move salts around so I want to focus in on these little orange particles as being salts or we can also call them ions now now what we are trying to do is we want to consistently move these salts or these ions into our root because um in order to facilitate osmosis wherever salt is water is going to be attracted to salt and it's going to go wherever it is so do you see why this is important if there's salt on the outside we want to put salt inside the root hair because salt will move in and therefore water will move in and so there's this passive um uh osmosis of water in the difficulty is salt is often going to be moving from a low concentration to a high concentration and that is where our mitochondria come in play they create a um pump system where it can actively um allow salts to move from a low concentration to a high which means moving from outside of the cell into the cell and in doing so that then will create a high water potential that always pulls in water from the outside now to illustrate this I have a little animation here about the movement of water from the root hair to the xylem now essentially what's going to happen is our water is going to move through our root hair and it's going to move into the root cortex which is the majority of like that parenchima tissue now it gets past this yellow zone over here which contains something called The casparian Strip now the casparian strip is waterproof um it sits on the outside of the cell so not inside the cell but essentially its purpose is to force the water particles into the xylm otherwise they wouldn't leave the cortex and so when we go through this Zone it forces the water to go through the cytoplasm of those cells and then into the xylm the xylm is of course going to then take that water and transport it upwards it's also important to note that when we transport water via xylm it only Moves In One Direction and water only moves from the bottom to the top um in order to maintain things like for example root pressure and also to facilitate things like transpiration now as always I like to finish off my videos with a terminology recap you can use these for your flashcards for a terminology list and it's important to learn these words because this is what gets you marks when you answer questions is using the correct term so at the very beginning we spoke about osmosis which is the movement of water from a high to a low concentration and we also spoke about the fact that root hair cells lack a cuticle which remember is that protective layer on the outside um of other epidermal cells but remember they lack the cuticle because they they don't want to be waterproof so no cuticle on root hair cells we spoke about the word water potential the term water potential and water potential literally means what is the amount of water in that area and we generally move from a high water potential to a low water potential now how do you create that potential I spoke about ions or salts and that is when we are going to actively pump salts against the concentration gradient so from a low to a high and we use mitochondria for that and that makes the root hair cells very salty on the inside and remember wherever salt is water goes and so what happens is the salts inside the root hairs attract the water towards them therefore improving absorption we spoke about the root cortex very uh recently when we looked at how water moves from the root hair all the way into the xylm speaking of xylm remember that is the vascular tissue that transports water and lastly we also mentioned something called The kasparan Strip which is a waterproof roof layer that forces water from the cortex into the xylm now in our next video that's going to follow this we are going to do the three water Roots so the different Roots um water take which is app plastic Sim plastic and vacular so you better stick around for that video because it's going to be coming up next now if you like this video don't forget to give it a thumbs up and make sure you're subscribed with your notifications turned on because I post every Tuesday and Thursday and I will see you all again soon bye