21c Part 1 STEM CELLS National 5 Biology Unit 2 Multicellular Organisms 1052019 1 Mrs Smith National 5 Biology Learning Intentions National 5 Biology 1052019 2 Mrs Smith National 5 Biology ID: 910353
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Key Area 2.1: Producing New Cells2.1c: Part 1 - STEM CELLS
National 5 Biology
Unit 2: Multicellular Organisms
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Mrs Smith - National 5 Biology
Slide2Learning Intentions
National 5 Biology
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By the end of this Key Area,
You should be able to describe that stem cells in animals can divide and have the potential to become different types of cell. Stem cells are involved in growth and repairYou should also investigate the potential uses of stem cells and discuss ethical issues associated with their use.
Slide3Stem Cells: Introduction
It has been estimated that in one day, you will shed about a million skin cells.These have to be replaced.
This requires a supply of new cells as well as maintaining the original population of cells which gives rise to the new skin cells.The original population is made up of cells not yet committed but can form specialised skin cells.
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Slide6Stem Cells: 3 features
Unspecialised (uncommitted) cells are called stem cells and are extremely important in animals.
They have 3 important featuresEven though they are UNSPECIALISED, they have the potential to develop into various types of specialised cell when required. e.g. to replace cells that have come to the end of their life or have been damaged or lost.Reproduce themselves repeatedly (without limit) by repeated mitosis and division while remaining unspecialised.Divide in order to self-renew
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Slide7There are two types of stem cells in animals
1.Embryonic stem cells 2.Tissue (Adult) stem cells
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Slide81. Embryonic stem cells
An early human embryo contains EMBRYONIC STEM CELLS.These are capable of developing into all cell types found in the human body.They even have the potential to regenerate an entire organ from just a few cells.
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Slide91. Embryonic stem cellsif given the chemical and electrical signals can become any cell
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Slide102. Tissue (adult) stem cells
A fully formed human possesses TISSUE STEM CELLS at various locations such as the bone marrow, blood and skin.These cells have a more limited potential than embryonic stem cells.
Under natural conditions, tissue stem cells are only able to replenish the supply of one or more types of specialised cell closely related to the tissue in which they are found.10/5/2019
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Slide112. Where are tissue stem cells found?
Stem cells are found in different places in an animals body such as:Bone marrow
TeethLungsHeartBrain
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Slide122. Example: Tissue (adult) stem cells
Tissues stem cells in skin can only produce more skin cells.
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Slide132. Example: Tissue (adult) stem cells
Tissue stem cells in red bone marrow can only give rise to new blood cells.
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Slide14Current uses of stem cells.
Human stem cells can be grown in cultures provided that they are given optimum conditions and certain key growth factors.Stem cells have been put to use in some of the following ways Bone marrow transplantation.
Skin GraftCornea Repair.10/5/2019
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Slide15Current uses of stem cells.1. Bone marrow transplantation.
Some forms of cancer of the blood such as leukaemia result from the uncontrolled increase in the number of white blood cells.One form of treatment involves destruction of the patients cancerous bone marrow cells and their replacement with a transplant of normal, blood forming stem cells from a suitable donor.
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Slide16Current uses of stem cells.2. Traditional Skin Graft
In a traditional skin graft, a relatively large section of skin is removed from a region of a persons body and grafted to the site of injury.
This means that the person has two parts of their body that need careful treatment and time to heal.
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Slide17Current uses of stem cells.2. Stem Cell Skin Graft
A skin graft using stem cells only requires a small sample of skin to be taken to obtain stem cells.
The site needs much less healing time and suffers minimum scarring.Because this technique uses the patients own cells there is no risk of the tissue being rejected.
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Slide182. Skin GraftSpray on stem cell skin graft
A small sample of skin cells taken from an area close to, and similar in structure to, the site of injury.
Enzymes are used to isolate and loosen the stem cells, these are then cultured.Once a suspension of new stem cells had developed, they are sprayed over the damaged area to bring about the regeneration of the missing skin.
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Slide19Current uses of stem cells.3. Cornea (part of eye) repair.
In recent years scientists have shown that corneal damage by chemical burning can be successfully treated using stem cell tissue.This can be grown from the patient’s own stem cells located at the edge of the cornea.
Because this technique uses the patients own cells there is no risk of the tissue being rejected. 10/5/2019
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Slide20Current uses of stem cells.
3. Cornea (part of eye) repair.
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Slide21MORE Potential Uses of stem cells.
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Slide22BBC CLIP: How do stem cells actually work?
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Slide23Future therapeutic potential of stem cells
Embryonic stem cells are able to differentiate into any type of cell in the body.Because of this they could have the potential to provide treatments in the future for a wide range of disorders and regenerative conditions that current medicine cannot cure, e.g.
Diabetes, Parkinson's disease.Alzheimer's disease.Multiple sclerosis.
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Slide24Key Area 2.1: Producing New Cells2.1c: Part 2 – The ethics associated with the use of STEM CELLS.
National 5 Biology
Unit 2: Multicellular Organisms
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Slide25Ethics
Ethics refers to the moral values and rules that ought to govern human conduct (behaviour).The use of stem cells raises several ethical issues.
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Slide26Stem cell research!
Stem cell
research.
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Slide27Stem cell research controversy
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The interplay between religion, ethics, legal issues, commercial interests and Government policies have made the stem cell research a very controversial topic
Slide28Ethics: Human embryonic stem cellsBall of cells vs Human being????
At present , the creation of a continue of continuous embryonic stem cells (stem line) for research purposes makes use of cells take from a human embryo of no more than 14 days’ growth.
Some people find this unethical because it results in the destruction of a human embryo (usually from ivf, the spare ones no-one needs)
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Slide29Ethics: Human embryonic stem cellsInterspecies cocktail??????
NUCLEAR TRANSFER TECHNIQUE.
The nucleus of the egg cell of one animal is removed and replaced with that from another (donor cell).e.g Cow egg cell nucleus replaced with human skin cell nucleus. These cells are allowed to divide and are used for scientific research!This produces a hybrid (not 100% human), but can help research continue when there is a shortage of human embryonic cells.10/5/2019
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Slide30Ethics: Should we use nuclear transfer to bring back the MAMMOTH????
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Slide31Ethics: Should we use nuclear transfer.. What about a Neanderthal Man?????
http://www.telegraph.co.uk/science/9814620/I-can-create-Neanderthal-baby-I-just-need-willing-woman.html
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Slide32Debate Instructions
As you walked in the door you will be given a playing card Ace (1-4), Spade(1-4), Diamond(1-4), Heart(1-4). This is important as your role in the debate will depend on this card.We will flip a coin. Heads means your group is in favour of the debate. Tales means they are against the idea.
For Debate 1 (ACE AND SPADES) you will have an information sheet to help you with your arguments. – You have 15 minutes to prepare your argument then each group will have 5 minutes to present your argument.For Debate 2 (DIAMONDS AND HEARTS)listen to the podcast to help with your arguments. You have 15 minutes to prepare your argument then each group will have 5 minutes to present your argument.10/5/2019
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Slide33Roles – Depending
Your number
Opening Statement Presenter: (1 min.)
Gathers the main arguments into an introductory statement. Does not give specific information; just says "this is true because of A and B and C."
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Topic Presenters: (3 min.)Present the main arguments for the team. Each presenter gives specific details that prove A and B and C.
Closing Statement Presenter: (1 min.)
Presents the closing arguments for the team. Repeats the main idea for this and this and this reasons.
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Slide34Debate 2.
Debate 1.
Is it ethically moral to……
grow an ear from stem cells on the back of a mouse?
Designer babies (Genetically engineered babies) will improve the human race!
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Slide35What is a stem cell?
State 3 features of a stem cell.What are the two types of stem cell?Name two places in the human body where adult stem cells are found.
What do we currently use stem cells for?Name two other potential uses for stem cells.What are some of the ethical considerations of using stem cells?
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Slide36Have you achieved your learning Intentions
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Can you…….
Describe that stem cells in animals can divide and have the potential to become different types of cell. Explain that stem cells are involved in growth and repairInvestigate the potential uses of stem cells.Discuss ethical issues associated with stem cell use.