Unit_1__Organisation_in_life_Part3.pdf

Academic Year 2024-25 Unit1: Organization in Life Grade: MYP 4 Key concept: Systems Related concept: Pattern, Function Global context: Identities and relationships Students will explore identity formatio...

Academic Year 2024-25 Unit1: Organization in Life Grade: MYP 4 Key concept: Systems Related concept: Pattern, Function Global context: Identities and relationships Students will explore identity formation. SOI: Our identity is determined by the relationship between different patterns and functioning of the cells which work together to create a larger, functioning system. Purpose of the Notes: The purpose of giving notes for above topics is to provide students with a condensed and organized summary of the important information and knowledge covered in the lesson. Notes help students consolidate information, serve as a reference for later review, visually represent complex ideas and support personalized learning. Learning outcomes: Define stem cells and explain their potential to develop into various cell types. Differentiate between embryonic and adult stem cells. Describe the applications of stem cells in medical treatments and research. Discuss the benefits and risks associated with the use of stem cells. STEM CELLS Introduction: What are stem cells, and why are they important? Stem cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell. Stem cells are distinguished from other cell types by two important characteristics.  o First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. o Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions. Source: Bbc Bitsize, bam.files.bbci.co.uk/bam/live/content/z8ntfg8/large. Source: Bbc Bitsize, bam.files.bbci.co.uk/bam/live/content/z8ntfg8/large.  History of Stem cells: Until recently, scientists primarily worked with two kinds of stem cells from animals and humans: embryonic stem cells and non-embryonic "somatic" or "adult" stem cells. Scientists discovered ways to derive embryonic stem cells from early mouse embryos more than 30 years ago, in 1981. The detailed study of the biology of mouse stem cells led to the discovery, in 1998, of a method to derive stem cells from human embryos and grow the cells in the laboratory. These cells are called human embryonic stem cells. The embryos used in these studies were created for reproductive purposes through in vitro fertilization procedures. When they were no longer needed for that purpose, they were donated for research with the informed consent of the donor. In 2006, researchers made another breakthrough by identifying conditions that would allow some specialized adult cells to be "reprogrammed" genetically to assume a stem cell-like state. This new type of stem cell, called induced pluripotent stem cells (iPSCs), will be discussed in a later section of this document. Importance of stem cells: Stem cells are important for living organisms for many reasons. In the 3- to 5-day- old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lungs, skin, sperm, eggs and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease. Given their unique regenerative abilities, stem cells offer new potentials for treating diseases such as diabetes, and heart disease. However, much work remains to be done in the laboratory and the clinic to understand how to use these cells for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine. Laboratory studies of stem cells enable scientists to learn about the cells’ essential properties and what makes them different from specialized cell types.  Scientists are already using stem cells in the laboratory to screen new drugs and to develop model systems to study normal growth and identify the causes of birth defects. Research on stem cells continues to advance knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. Stem cell research is one of the most fascinating areas of contemporary biology, but, as with many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new discoveries. Source: Mar. 2018, pediaa.com/wp-content/uploads/2018/03/Copy-of-How-are-Restriction-Enzymes-Used-in-DNA-Fingerprinting- Infographic.jpg.  What are the differences between embryonic and adult stem cells? Source: Mar. 2018, pediaa.com/wp-content/uploads/2018/03/Copy-of-How-are-Restriction-Enzymes-Used-in-DNA-Fingerprinting- Infographic.jpg. APPLICATIONS OF STEM CELLS In people who suffer from type 1 diabetes, the cells of the pancreas that normally produce insulin are destroyed by the patient's own immune system. New studies indicate that it may be possible to direct the differentiation of human embryonic stem cells in cell culture to form insulin-producing cells that eventually could be used in transplantation therapy for persons with diabetes. Scientists manipulate stem cells so that they possess the necessary characteristics for successful differentiation, transplantation, and engraftment. To be useful for transplant purposes, stem cells must be reproducibly made to: Proliferate extensively and generate sufficient quantities of cells for making tissue. Differentiate into the desired cell type(s). Survive in the recipient after transplant. Integrate into the surrounding tissue after transplant. Function appropriately for the duration of the recipient's life. Avoid harming the recipient in any way. They could be used to replace cells or tissues that have been damaged or destroyed, eg: o in Type 1 diabetes o in cases of multiple sclerosis, which can lead to paralysis o in cases of spinal cord or brain injury, that have led to paralysis Benefits and risks associated with the use of stem cells in medicine: Stem cells have great potential in treating patients with currently untreatable conditions, growing organs for transplants, and in scientific research. But there are clinical, ethical and social issues with their use. These issues will be different for growth and transplant of adult, embryonic and therapeutically cloned stem cells. They will also depend on whether the stem cells are to be used for therapy or research. The benefits of the therapy must be weighed up against any risks and ethical concerns. It is important to obtain a balanced view. Sometimes, there are no right or wrong answers, or even answers at all. Some variables which would be considered when discussing stem cells include: Clinical issues There is no guarantee how successful these therapies will be, for example, the use of stem cells in replacing nerve cells lost in Parkinson's disease patients.  The current difficulty in finding suitable stem cell donors. The difficulty in obtaining and storing a patient's embryonic stem cells. These would have to be collected before birth - some clinics offer to store blood from the umbilical cord when a person is born. Mutations have been observed in stem cells cultured for several generations, and some mutated stem cells have been observed to behave like cancer cells. Cultured stem cells could be contaminated with viruses which would be transferred to a patient. Ethical issues A source of embryonic stem cells is unused embryos produced by in vitro fertilisation (IVF). Embryos could come to be viewed as a commodity, and not as an embryo that could develop into a person. At what stage of its development should an embryo be regarded as, and treated as a person? Economic issues Stem cell research can be expensive due to the need for advanced equipment, specialized facilities, and skilled researchers. Securing consistent funding for such research can be a challenge, especially for long-term projects. Developing new therapies or treatments based on stem cell research requires substantial investment in clinical trials, testing, and regulatory approvals. The costs associated with bringing a stem cell therapy to the market can be significant. Though stem cell research can contribute to job creation in various sectors, including research institutions, pharmaceutical companies, and healthcare facilities, once stem cell therapies are developed, they may come with high price tags due to the complex manufacturing processes, research costs, and limited availability. This can raise concerns about equitable access to these treatments, particularly for individuals with limited financial resources. Guiding Questions: 1. Outline the differences in embryonic and adult stem cells in terms of their origins and capabilities? 2. Describe the benefits and risks associated with using stem cells in medical therapies and research. 3. Explain the potential applications of stem cells in medical treatments, focusing on conditions like type 1 diabetes and multiple sclerosis. Resources: Books: MYP Biology 4/5: A Concept Based Approach. By- David Mindorff and Andrew Allott MYP by concepts 4 & 5. By- Andrew Davis and Patricia Websites: “Stem Cell Basics I.” National Institutes of Health, U.S. Department of Health and Human Services, stemcells.nih.gov/info/basics/1.htm https://www.bbc.co.uk/bitesize/guides/zghqfcw/revision/8