1. Chapter 10: Stem Cells & Meristems PART 1 – STEM CELLS
National 5 Biology
Unit 2: Multicellular Organisms
Chapter 10: Stem Cells & Meristems PART 1 – STEM CELLS
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Mrs Smith - National 5 Biology

2. Mrs Smith - National 5 Biology
Learning Intentions
By the end of this chapter,
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 repair
You should also investigate the potential uses of stem cells and discuss ethical issues associated with their use.
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Mrs Smith - National 5 Biology

3. Stem 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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4. Mrs Smith - National 5 Biology
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5. Mrs Smith - National 5 Biology
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Stem Cells: 3 features
These uncommitted cells are called stem cells and are extremely important in animals.
They have 3 important features
They are UNSPECIALISED cells. Not yet committed to being a particular type of cell.
Reproduce themselves repeatedly (without limit) by repeated mitosis and division during an animals lifetime.
Divide to form two daughter cells. Each may still be unspecialised or develop into various types of specialised cells when required, for example to replace cells that have come to the end of their life or have been damaged or lost.
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7. Mrs Smith - National 5 Biology
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Mrs Smith - National 5 Biology

8. Where are stem cells found?
Stem cells are found in different places in an animals body such as:
Bone marrow
Teeth
Lungs
Heart
Brain
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9. There are two types of stem cells in animals
1.Embryonic stem cells Tissue (Adult) stem cells
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10. Mrs Smith - National 5 Biology
1. 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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11. Mrs Smith - National 5 Biology
1. Embryonic stem cells
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Mrs Smith - National 5 Biology

12. 2. 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.
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Mrs Smith - National 5 Biology

13. 2. Example: Tissue (adult) stem cells
Tissues stem cells in skin can only produce more skin cells.
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Mrs Smith - National 5 Biology

14. 2. Example: Tissue (adult) stem cells
Tissue stem cells in red bone marrow can only give rise to new blood cells.
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Mrs Smith - National 5 Biology

15. Potential 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 Graft
Cornea Repair.
We will look at these uses in more detail, but...
THERE ARE MANY OTHER WAYS TO USE STEM CELLS
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Mrs Smith - National 5 Biology

16. MORE Potential Uses of stem cells.
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17. Potential 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.
Once treatment involves destruction of the patients cancerous boneg s marrow cells and their replacement with a transplant of normal, blood forming stem cells from a suitable donor.
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Mrs Smith - National 5 Biology

18. Potential 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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Mrs Smith - National 5 Biology

19. Potential 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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Mrs Smith - National 5 Biology

20. 2. Skin Graft Spray 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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Mrs Smith - National 5 Biology

21. Potential Uses of stem cells. 1. 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.
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Mrs Smith - National 5 Biology

22. Potential Uses of stem cells. 3. Cornea (part of eye) repair.
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Mrs Smith - National 5 Biology

23. Future 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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24. Mrs Smith - National 5 Biology
Ethics
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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25. Mrs Smith - National 5 Biology
Stem cell research!
Stem cell
research.
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26. Stem cell research controversy
The interplay between religion, ethics, legal issues, commercial interests and Government policies have made the stem cell research a very controversial topic
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27. Ethics: Human embryonic stem cells Ball 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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Mrs Smith - National 5 Biology

28. Ethics: Human embryonic stem cells Interspecies 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.
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29. Ethics: Should we use nuclear transfer to bring back the MAMMOTH????
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30. Mrs Smith - National 5 Biology
Ethics: Should we use nuclear transfer.. What about a Neanderthal Man?????
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31. Mrs Smith - National 5 Biology
Debate 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.
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32. Opening Statement Presenter: (1 min.)
Roles – 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."  -
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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Mrs Smith - National 5 Biology

33. Debate 1.
Designer babies (Genetically engineered babies) will improve the human race!
Debate 2.
Is it ethically moral to……
grow an ear from stem cells on the back of a mouse?
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Mrs Smith - National 5 Biology

34. Chapter 10: Stem Cells & Meristems PART 2 – MERISTEMS
National 5 Biology
Unit 2: Multicellular Organisms
Chapter 10: Stem Cells & Meristems PART 2 – MERISTEMS
4/17/2017
Mrs Smith - National 5 Biology

35. Mrs Smith - National 5 Biology
Learning Intentions
By the end of this chapter you should know
Meristems are the sites of production of non-specialised cells in plants and are the sites for mitosis in a plant. These cells have the potential to become other types of plant cell and they contribute to plant growth.
Be able to carry out practicals on root tip/shoot tip stain.
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Mrs Smith - National 5 Biology

36. Mrs Smith - National 5 Biology
Meristems
Whereas most multi-cellular animals stop growing on reaching maturity, multi-cellular plants continue to grow throughout their life.
Also growth in animals happens all over its body but in plants production of new cells takes place only at areas called MERISTEMS.
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Mrs Smith - National 5 Biology

37. Meristems are found at the tips of roots and the tips of shoots
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Mrs Smith - National 5 Biology

38. Mrs Smith - National 5 Biology
Meristems
Meristems are made of non-specialised cells that undergo continuous division.
Some cells made are meristematic (can divide again producing more non-specialised cells that have the potential to become any type of plant cell).
Others become elongated and then develop into specialised cells and tissues.
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Mrs Smith - National 5 Biology

39. Meristems: APICAL and LATERAL
Meristems consist of relatively small cells that can grow and mature to form new plant tissue.
Meristems found at the tips of growing plants are called APICAL.
Meristems found towards the outside of roots and are called LATERAL.
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Mrs Smith - National 5 Biology

40. APICAL and LATERAL Meristems
Activity in apical meristems results in the increased length of a root or shoots.
Activity in lateral meristems results in the increased width of a root or shoot.
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Mrs Smith - National 5 Biology

41. Apical meristems – root tips
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Mrs Smith - National 5 Biology

42. TASK: Examining a stained root tip meristem to observe mitosis
Mitosis is the cell process where cells divide into two.
Mitosis involves many stages which ensure that the correct genetic information on chromosomes is contained within each daughter cell.
View the root tip slides using a microscope and try to spot cells which are undergoing mitosis at the following stages:
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Mrs Smith - National 5 Biology

43. Mrs Smith - National 5 Biology
TASK - Worksheet
Now collect the root meristem worksheet and stick it into your jotter. Answer the questions.
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Mrs Smith - National 5 Biology

44. Apical meristems – shoot tip
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Mrs Smith - National 5 Biology

45. Mrs Smith - National 5 Biology
TASK - Worksheet
Now collect the shoot meristem worksheet and stick it into your jotter. Answer the questions.
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Mrs Smith - National 5 Biology

46. Mrs Smith - National 5 Biology
What is a stem cell?
State 3 features of a stem cell.
Name two places in the human body where stem cells are found.
Which of the following statements are not true?
Stem cells cannot grow in large numbers.
Growth takes place all over the body of a plant.
Meristems can produce an increase in the width of a tree.
During the lifetime of an animal, stem cells can divide repeatedly.
How does an apical meristem differ from a lateral meristem?
Name two locations in a plant where a meristem would be found.
Give two differences between a meristematic cell and a xylem vessel.
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Mrs Smith - National 5 Biology

47. Mrs Smith - National 5 Biology
Glossary
Stem cells
Unspecialised cell
Specialised cell
Embryonic Stem Cells
Ethical
Meristems
Apical Meristem
Lateral Meristem
Nuclear transfer technique
Tissue stem cells,
Hybrid
Mitosis
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Mrs Smith - National 5 Biology