Video: Stem cells and the use of stem cells

﻿Hello everyone. Welcome back to Combined Science for Key Stage Four. This is Miss Wong again review in cell biology. Today we are going to look at stem cells. We are going to talk about what they are and how do we use them? We will go through some of the very main points of where to find stem cells and the ethical issues and the concerns around the use of stem cells. Let's have a look at the equipment you need today. In today's lesson you will need a pen, paper, or a book to complete all the tasks. Please make sure that you have these with you now. Also, I would like you to switch your phones and close all other unwanted browsers tabs before we move on into the lesson content. Please do it now, if you need more time pause the video and come back when you are ready. Let's have a look at today's agenda. Today's agenda will cover the following items, first of all, we going to need to revise on the nature of stem cells, then we'll learn about the use of stem cells and then we want to evaluate the advantages and disadvantages of the use of stem cells. First of all let's talk about the human body. We want to think about where do we find stem cells? So just to recap stem cells, we have previously gone through this before. They are very very important as they were where all our specialised cells came from. These are very simple cells without any adaptations. So they exist as just a bowl of very simple animal cells in this case and on the left-hand side here, this is showing you an embryo and these cells are very undifferentiated. That means they have the potential to become any cells in the human body. And of course, we're talking about human body and they will follow the structure of a very simple animal cell. For example, they have the cytoplasm in their nucleus, they have the cell membrane and they also have mitochondria to release energy during respiration. So what happens is we want to think about the differentiation of stem cells. We have talked about this before in this specialised cells lesson. But then of course we want to recall and remind ourselves the importance of having stem cells. Stem cells again, is where every single specialised cell came from. So stem cell is where every single specialised cell came from. A very simple cell it differentiates to give you many many other cells with different adaptations. And of course, how it would develop is controlled by the genetic content. Now we will have look at where to find stem cells in our human bodies. So you have the human stem cells of course we're talking about our human bodies, and then we want to think about the two big types of stem cells. The first type is the embryonic stem cells. From it's name we can tell that the embryonic stem cells is actually from the embryo. It can differentiate into all types of cells and again it's from embryos. So unfortunately I'm an adult now so I wouldn't be able to have any of the embryonic stem cells. So for me, I would have the adult stem cells. The other stem cells can only differentiate into certain type of cells for example, blood cells. And how do I get it? And you get it from the bone marrow, which is the soft tissue protected by your bones. One example is the spine, so I'll have to go into my spine to get my adult stem cells. Let's have a look at the advantages and disadvantages of the use of stem cells. Stem cells are very important at the moment because there are some diseases that are very hard to treat, and with stem cells we can stimulate the stem cells and you can specialise into the type of cells that we're looking for. And potentially, the stem cells can differentiate to give us new tissues that we can use to replace the diseased tissues in our body. However, there are several advantages and disadvantages. Let's have a look at the advantages and disadvantages of the use of embryonic stem cell first. So the advantages are, you can create many embryos, it's quite efficient. Where are they from? They are from donated embryos. And it is a painless technique, so it's not going to harm anybody. You can treat many diseases because it can differentiate into any type of cell. But it comes with several disadvantages as well. First of all, sometimes we have, let's say you have got 50 embryos because you stimulated them and they grew in the lab, but possibly you don't need all 50. Is it something right to do to dispose off embryonic cells? Some people regard the embryo as the beginning of life. So the argument is if you dispose embryos, you are disposing somebody, an individual that is alive. Is that something correct to do? Also if you use the stem cells, the embryos for any medical purposes, the embryo even though it is it can be regarded as an individual. It does not have any consciousness yet. That means embryo cannot give consent to any medical use of the embryonic stem cells themselves. And sometimes it's a little bit reliable because the scientists are still getting better and better at how to control the growth and differentiation of stem cells and sometimes if it gets a bit out of control, it can potentially develop into a tumour, which is a cancer cell because the cells keep on dividing without stopping. Also, we can consider another type of stem cells that can be used for medical purposes. For the adult stem cells the advantages are, the first thing there is no ethical issues because you are literally taking cells from an adult. And an adult can give consent to how the cells can be used. It can treat some diseases, not all diseases because the cells cannot divide into all types of cells, but the procedure is relatively safe. It can be painful because you need to again go into the spine and take out the cells from bone marrow. It can be painful, but it's rather safe and reliable and even if I run through that process I will recover from that process really quickly. So it's not going to give me any permanent damage. However, here comes with some disadvantages of the adult stem cells. So if I am going into my spine to take out some cells, I am creating the opportunity for bacteria, for other viruses to enter my body, there's a risk of infection. And even if I've done it in a hospital when I'm recovering from it there is still some risks of infections. It only treat a few diseases like leukaemia, and the procedure can be painful as I mentioned you need to go into the spine. So that can be a bit painful. So I would like you to think about what we have just discussed. These are the two questions I would like you to think about now. I would like you to pause the video, answer these two questions and then come back to check the answers. Pause the video now. Here are the answers let's check. Make sure you have written down your answers. The answers are, because the embryo cannot give consent to how it will be used, and some embryos will be disposed. Also, some people think that again the embryo is an individual, so it's very controversial. And then the second one is embryonic stem cells. It is a type of cells that can differentiate to any type of specialised cells. Mark your answers, if you need more time pause the video, if you are ready, we will move on. Let's try exam question. One mark, quite quick actually but if you need more time, please pause the video. Scientists have been able to make working thyroid cells from stem cells. So they stimulate stem cells to create more thyroid cells. They use embryonic stem cells. How are embryonic stem cells different to adult stem cells? Okay, pause the video, write down the answer and see if you can get this mark in the exam. Let's see if we can get the mark here. Embryonic stem cells can become all types of cells of the body, while adult stem cells are thought to be limited to differentiating into different types of cells. So you cannot differentiate one adult stem cells to all types of cells while the embryonic cells can. So there is more potential for the embryonic cells to be used in other medical purposes. This is a longer one, this is a three-mark question. So the kidneys in people with ARPKD which is a disease, have not developed normally. Stem cells could be used to repair the damaged kidneys. Discuss reasons for and against using stem cells to treat the disease. So the key point is you want to list out at least three points for and against. Remember, for and against using stem cells to treat diseases. This will take a bit longer. Pause the video now, pick a pen and write down your answers. Come back when you are ready to check your answer. Let's have a look at the answers. So you need any three, any three but you must have at least one argument for and one arguments against. So pause the video here, check your answers and see if we can get three out of three. Let's move on. The next topic I would discuss is the therapeutic cloning process. So this is the process that we mass produce more stem cells for any medical purposes or research purposes. So for therapeutic cloning that means we want to have more stem cells on purpose. So we need to create a stem cell from an adult cell. So what do we do is this, if we go to the diagram on the board here, you can see that first of all , you have an egg cell and you have a human body cell. So let's assume that this is my human body cell, it would have my DNA in it. So the first step is, they would take my nucleus out of my cell. So this nucleus here will contain my DNA in it. And for this egg cell is not necessarily from me, it can be from a donor. But for this egg cell, they will remove that nucleus but want the cell membrane and the cytoplasm. So here we have one cell membrane and cytoplasm from someone else, and you have the nucleus of my cell, so that's my DNA there. So what you can do is you can merge, you can fuse the nucleus into the egg cell without the nucleus obviously. So the nucleus is fused into this egg cell and this will become an egg cell carrying my DNA and this will be an embryo. Because I have my full set of DNA inside an egg cell. So this cell is ready to go. And then you will stimulate the cell and make the cells divide and make more copies of themselves through one type of cell division, which is if you remember yes, that is mitosis. So we will have a lot of embryonic cells carrying my DNA And these cells possibly can be used to differentiate into let's say blood cells, to cure any diseases I have. So this is the process of therapeutic cloning. Now let's have a look at if you can reproduce the steps of therapeutic cloning. So on the board here, I have one, two, three, four, four statements and what I would like you to do is to pause the video, pick a pen and try to rearrange them into the correct order because I have put them into the wrong order. Pause the video now, reorder the sentences and come back to check for your answers. Let's see if you have got the order correct. So the first step is a body cell is taken from the patient, let's say it's me and the nucleus is separated from the cell. So they take out my nucleus. And then the nucleus from me, from the patient is fused with an empty egg cell from the donor. And then the cells are stimulated to divide and develop into an embryo and the stem cells are then available for therapeutic use. So we will create quite a lot of the stem cells and they can differentiate upon different stimuli, due to different types of cells. Check and make sure that you have got the steps correct. We have gone through the session on looking at the advantages and disadvantages and the use of stem cells in a human body. And now I'm going to talk to you about plant stem cells. So stem cells also exist in plants. And we are going to talk about a specific region of the plant that is called the meristem or meristems in plural. So on the picture here on the left hand side, you can see that there is a plant and this plant they have had a cut right at the top. And if you leave this plant for a while, this is what you will see. You will see the new growth of leaves and they are coming up from the top as well. Why does this happen? It's because at the top region, the tip of the shoot referring to the top tip of the plant, we have some stem cells in the plant meristems. And if you cut it, these stem cells can differentiate and form new cells. So they've formed new leaves as a result here. And this is not the only sample, stem cells of plants are not only located at the tip of the shoot. It can also be found in the tip of the roots. Let me show you another picture. So if you look at here, we can see that there's these leaves and these are cuttings of the same plant, they all look the same. So what happens is, the roots and the tip has got the meristem, has got the stem cells that allow the plants to propagate and make clones of themselves. And here is a picture that I would like you to think about the shape , the colour and of all these individual plants. Is it quite obvious that they look pretty much the same. So it's very likely that you have one mother plant. And then you cut off the different bits of the shoot, and then you re-pot them into the soil and it will give you the clones of the same plant. And for these leaves they're the same. If a leaf comes off a plant and you leave it on the side leave it on the soil, the stem cells at the end of the leaves will differentiate to give you roots and will differentiate to give you leaves as well. So to give you an example, I can show you something. So to propagate plants is actually very easy, and here is my little bit of a propagation tray. I can pick up one and show you very clearly what I mean by differentiation of stem cells. So if I pick this one up, you can see that this is only a leaf. And you can see that there are roots at the bottom holding the soil, and there are leaves at the top as well. So all these structure are formed from one single leaf which is this one. And I will expect the genetic material of the small little shoot will be the same as the genetic material of the whole leaf here. So I'm making clones of the same plant. Now I would like you to pause the video and complete this task here. I would like you to write down your answers in your books, and then come back when you've finished the task. Okay, let's have a look at the answers. So to find the stem cells of plants, you need to go into the meristem of the plant, you can find them in the tip of shoot or the roots. And if you want to do some cloning in farming is actually very quick. You can produce a large population of plants quickly, and these plants will have the same characteristics as the mother plants. That means if you clone a tomato plant that produces large and red, very bright red tomatoes, then you can have potentially a field of tomato plants with bright red and big tomatoes. Now we'd like you to have a go at this exam style question. Usually in exam, they will give you any question and this question will ask you numerous different smaller questions from different topics. So I put together this question and it will assess you on your knowledge in previous lessons that we have done together. I would like you to pause the video now and answer these question in details. The brackets at the end of each question tells you how many marks you can score at the maximum in that particular question. If it says three marks please at the minimum, write down three points so that you can get all three marks. Pause the video now and resume the video when you're ready to check the answers. Okay let's have a look at the answers make sure that you've attempted every single one of them. So number one, the meristem located at the shoot or root tip. And for number two, you would need to do a little bit of unit conversion before you can use the calculation using the magnification equation. So two millimetres were equal to 2000 micrometeres, because each millimetre would contain 1000 micrometeres and therefore you do division. And the answer is five micrometres. Now, number three. Mitosis is a type of cell division that is involved when the plants grow bigger getting new cells to replace the old ones. And number four, the mother and daughter cells are genetically identical. That means the mother and daughter plants, if they grew into newer individuals they will be genetically identical and we can call them clones of each other. In this lesson, we have gone through the advantages and disadvantages of the use of stem cells. Which is very important because that might come up as a longer response answer in your exam. Also we have went through the stem cells in plants and we have think about how making clones is actually useful in farming. Making clones of plants can actually produce a field of many many plants that can give you your desired products. Thank you very much for joining me today. I would like you to move on to the independent practise and the exit quiz. I hope to see you again in the next lesson.

Worksheet: Stem cells and the use of stem cells

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This lesson will cover the two types of stem cells and how the stem cells can be used in the medical field. It will also cover the advantages and disadvantages of the use of these two types of cells.

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Stem cells and the use of stem cells

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