Stem Cells Flashcards

All 18 cards in this deck

What is a stem cell?

An unspecialised cell that can divide to produce more cells that differentiate into specialised cells.

What does 'differentiation' mean?

The process by which a cell becomes specialised for a particular function.
e.g. a stem cell becoming a nerve cell

What is the function of embryonic stem cells?

They divide by mitosis and can differentiate into any type of cell in the body, forming all the tissues of the embryo.

Where are adult stem cells found in humans, and what is their function?

In bone marrow (and other tissues); they divide to replace damaged or worn-out cells, such as blood cells.

True or false? Adult stem cells can differentiate into any type of cell in the body.

False. Only embryonic stem cells can form any cell type; adult stem cells differentiate into a limited range, e.g. bone marrow stem cells form blood cells.

What are the steps by which stem cells produce the specialised cells of an embryo?
e.g. producing nerve cells

1. The stem cells divide by mitosis to make more cells.
2. The new cells differentiate to become specialised.
3. The specialised cells (e.g. nerve cells) form tissues and organs.

What is a meristem?

A plant tissue made of unspecialised cells (plant stem cells) that can divide.

Where are meristems found in a plant?

At the tips of roots and shoots (and in buds).

What is the function of meristem cells?

They divide by mitosis and differentiate into any type of plant cell, so the plant can grow throughout its life.

True or false? Plant meristem cells lose the ability to divide and differentiate once the plant is mature.

False. Meristems keep dividing and differentiating, so plants can grow throughout their lives.

How could stem cells be used to treat type 1 diabetes?

They could be made to differentiate into insulin-producing cells to replace the faulty cells in the pancreas.

How could stem cells be used to treat paralysis?

They could differentiate into nerve cells to replace damaged cells in the spinal cord, restoring movement.

Why is it a benefit to use stem cells taken from the patient's own body?

They match the patient's tissue type, so there is less chance of rejection and immunosuppressant drugs may not be needed.

Give three risks of treating a patient with stem cells.

Rejection of donor cells by the immune system; infection passed on during the procedure; the cells may divide uncontrollably and form a tumour.

Give one reason why some people object to the use of human embryonic stem cells.

The embryo is destroyed, and it has the potential to develop into a person.

True or false? All stem cells used in medicine have to be taken from embryos.

False. Adult stem cells (e.g. from bone marrow or umbilical cord blood) can also be used, and adult cells can be reprogrammed to behave like embryonic stem cells.

What are the steps to evaluate data about a stem cell treatment and give a judgement?
e.g. 6 out of 10 paralysed patients regained some movement in a trial

1. State what the data shows: most patients (6 of 10) improved.
2. Weigh the risks and limitations: 4 showed no benefit, small sample, possible tumours or rejection.
3. Give a judgement supported by the data: e.g. promising, but larger trials are needed before wide use.

True or false? A patient treated with stem cells from a donor may need to take immunosuppressant drugs.

True. The donor cells may not match the patient's tissue type, so the immune system could reject them.