4.1.2.3 Stem cells

What is a stem cell?

An undifferentiated cell which can undergo division to produce many more similar cells, with some differentiating to have different functions

What are the different types of stem cells?

Embryonic stem cells, adult stem cells, meristem in plants

How are embryonic stem cells formed?

When an egg and sperm cell fuse to form a zygote

How do scientists use embryonic stem cells?

They clone the cells through culturing them and direct them to differentiate into almost any cell in the body

What can embryonic stem cells potentially be used for?

Replace insulin producing cells in those suffering from diabetes, new neural cells for diseases such as Alzheimer’s, nerve cells for those paralysed with spinal cord injuries

Where can adult stem cells be found and what can they form?

If found in bone marrow, they can form many types of cells including blood cells

Where are meristems in plants found?

In root and shoot tips

What can meristems in plants be used for?

Making clones of the plant

Why might making clones of a plant be necessary?

If the parent plant has certain desirable features, for research, to save a rare plant from extinction

What is therapeutic cloning?

When an embryo is produced with the same genes as the patient and the embryo produced is harvested to obtain the embryonic stem cells, which can be grown into any cells the patient needs such as new tissues or organs

What is the advantage of therapeutic cloning?

They wouldn’t be rejected as they would have the exact same genetic make-up as the individual

What are benefits of research with stem cells?

They can be used to replace damaged or diseased body parts, unwanted embryos from fertility clinics could be used as they would otherwise be discarded, more research goes into the process of differentiation

What are problems of research with stem cells?

Removal of stem cells results in destruction of the embryo, people may have religious or ethical objections as it’s seen as interference with the natural process of reproduction, if the growing stem cells are contaminated with a virus, an infection can be transferred to the individual