Graffiti Using the coloured pen you have been given, visit as many as the posters around the room as you can and write down anything you know about the key terms or diagrams

End

stem cells

• Lesson Learning Outcomes:

Increasing Difficulty

Define the term stem

cell

Compare adult and embryonic stem cells and suggest

how they could be used to treat

diseases

Consider the ethical

implications of the use of stem

cells

Should we fund stem cell research?

Rainbow groups• YOUR TASK: in your group each person should pick a different

colour• Go to the corner of the room that corresponds to the colour you

picked• Read through the information and reduce it to three bullet points

on your sheet

End

Rainbow groups• Back in your groups!• Start with the person with the longest hair –

they should share what they have found out• Don’t forget to fill in your sheet!

End

Placemat Consensus• Now you have all the information about stem cells and

cell differentiation do you think scientists should be allowed to use stem cells to treat diseases?

• Pick a square around the edge of the placemat and write down what you think

Each person should pick a square and write in their square at the same time!

End

Placemat Consensus• Take it in turns to share your opinion – start with the

tallest person.• Come to a group consensus and write this in the middle.

Each person should pick a square and write in their square at the same time!

End

Travelling Heads• In your group number yourselves 1 – 4• Number…. are going to get up and move to another

group to share their groups consensus – do the other group agree? Can they change your mind?

What are stem cells?

• Stem cells are unspecialised ‘starting’ cells which differentiate and develop into specialised tissue cells.

Embryonic stem cells

• Embryos begin as a clump of embryonic stem cells, which then develop into all kinds of different cells in the body.

• Scientists believe embryonic stem cell research has enormous medical potential

Adult stem cells• Some cells in the human body can’t

reproduce, and have to develop from adult stem cells. These develop to form specialised cells, for example bone marrow stem cells develop into types of blood.

• Adult stem cells are already being used in medical treatments, like bone marrow transplants.

How could you make an embryo that only contained your genes?

Stem cells could be injected into damaged organs to rebuild the tissues. This would reduce the need for organ transplants.

The stem cells would need to have the same genes as the patient, otherwise they would be rejected by the patient’s immune system. They would need to be clones.

injected into patient with diseased liver

liver is repairedstem cells

Using stem cells

patient’sDNA inserted

stem cells removed – the embryo dies

5 day-old embryo

embryo cellnucleus removed

The DNA of an embryo cell can be replaced with the DNA from a patient’s cell.

The embryo produces stem cells containing the patient’s genes. The cells will not be rejected, so immune-suppressing drugs are not needed. This process is therapeutic cloning.

Human therapeutic cloning

Reflection

• Pick one of the following activities to complete:

1. Draw labelled pictures to summarise differentiated cells and stem cells

2. Compare the similarities and differences between therapeutic cloning and reproductive cloning

3. Consider the genetic disorders we have studied and you have heard about which one would you invest stem cell research into and why?

stem cells

• Lesson Learning Outcomes:

Increasing Difficulty

Define the term stem

cell

Compare adult and embryonic stem cells and suggest

how they could be used to treat

diseases

Consider the ethical

implications of the use of stem

cells

Should we fund stem cell research?

B1 - Done! • On your mobile phone

outline summarise the most important things you have found out during B1 on your mobile phone

B1 is amazing

because…

Differentiation• Most cells in your body are specialised for a particular job.

For one job it might be best to have a long thin cell and for another job it might be better to have a ball shaped cell.

• Cells have a particular structure that allows them to carry out a particular function

• Differentiation is the process by which a cell changes to become specialised for its job.

• Almost all cells contain the same instructions (genes). When a cell differentiates some of these genes are turned off and they never turn back on.

• In most animal cells the ability to differentiate is lost at an early stage, but lots of plant cells don’t ever lose that ability.

Stem Cells• Stem cells are undifferentiated cells. This means that they can

develop into different types of cell depending on the instructions they are given. They can continue to replicate indefinitely by mitosis.

• There are lots of different types of stem cells. In humans and many animals, it is only stem cells from early embryos that have the potential to turn into any kind of cell. These cells eventually disappear leaving adult stem cells.

• Adult stem cells are only found in certain places like bone marrow. These cells can only turn into a few types of cells (like white blood cells and red blood cells) and are used for replacement and repair.

• Plants have stem cells, called meristems. These cells are completely undifferentiated so they can turn into any type of cell. This is why trees can regrow branches if they get cut off.

Uses of Stem Cells• Medicine already uses adult stem cells to cure disease. For

example people with some blood diseases, such as sickle cell anaemia, can be treated by bone marrow transplants. Bone marrow contains stem cells that can turn into new blood cells that replace the faulty ones.

• Scientists can also extract stem cells from very early embryos and grow them. They hope that these stem cells could be used to replace cells in people with diseases caused by faulty cells. They could grow nerve cells for people paralysed by spinal injuries, insulin producing cells for people with diabetes or new heart muscle for people with heart disease.

• Lots of people don’t agree with the use of embryos for this so scientists are trying to find a way to switch on all the genes in adult cells – this will reverse differentiation.

Ethics of Stem cells• Some people are against stem cell research because they feel that

human embryos shouldn’t be used for experiments since each one is a potential human life

• Other people think that curing patients who already exist and who are suffering is more important than the rights of embryos.

• One argument for the use of embryos to produce stem cells is that the embryos used are usually unwanted one from fertility clinics, which if they aren’t used for research, would probably just be destroyed.

• Scientists are trying to find other sources of stem cells, so people could be helped without having to using embryos. In 2009 scientists used adult stem cells to replace the cells on a trachea donated for transplant. This prevented the recipients body from rejecting the transplanted organ. Scientists are also trying to generate stem cells using proteins so they don’t need to use stem cells at all.