Stem cells

Question 1

What are stem cells?

Answer 1

Unspecialised cells that can develop into other types of cells

Question 2

What happens when stem cells divide?

Answer 2

They become new cells and become specialised

Question 3

Where are stem cells found?

Answer 3

In the embryo
In some adult tissue

Question 4

What are totipotent cells?

Answer 4

Cells that can mature into any type of body cells.
They are present in mammals in the first few cell divisions of an embryo.

Question 5

What are pluripotent cells?

Answer 5

Cells that can still specialise into any cell in the body but lose the ability to become cells that make up the placenta

Question 6

Name the stem cells that are present in an adult mammal

Answer 6

Multipotent
Unipotent

Question 7

What are multipotent cells?

Answer 7

Cells that are able to differentiate into a few different types of cell

Question 8

What are unipotent cells?

Answer 8

Cells that can only differentiate into one type of cell

Question 9

Why can stem cells only become specialised during their development?

Answer 9

They only transcribe and translate part of their DNA

Question 10

Explain the process of how stem cells become specialised

Answer 10

1. Stem cells all contain the same genes but during development not all of them are transcribed and translated.
2. Some genes are expressed and some are switched off
3. mRNA is only transcribed from specific genes
4. the mRNA from these genes is then translated into proteins
5. these proteins determine the cell structure and control cell processes
6. changes to the cell produced by these proteins cause the cell to become specialised. These changes are difficult to reverse

Question 11

What are cardiomyocytes?

Answer 11

Heart muscle cells that make up a lot of the tissue in our hearts

Question 12

It is though that cardiomyocytes can’t what?

Answer 12

Divide to replicate themselves

Question 13

What do some scientists think about cardiomyocytes?

Answer 13

They think that old or damaged cardiomyocytes can be replaces by new cardiomyocytes derived from a small supply of unipotent stem cells of the heart

Question 14

What treatments can be given using stem cells?

Answer 14

• bone marrow treatments to treat leukaemia
• can be used to replicate damaged nerve tissue in spinal cord injuries
• replaced damaged heart tissue caused by heart attacks
• grow whole bladders to replace diseased ones
• donated windpipes can be stripped down to their simple collagen structure and then covered with tissue generated by stem cells
• organs can be grown

Question 15

What are the benefits of using stem cells in medical treatment?

Answer 15

To save lives
Improve the quality of life

Question 16

What are adult stem cells?

Answer 16

Cells that are obtained from the body tissues of an adult

Question 17

How are adult stem cells obtained?

Answer 17

In a relatively simple operate that has very little risk but can cause a lot of discomfort

Question 18

Why aren’t adult stem cells as flexible as embryonic stem cells?

Answer 18

They can only specialise into a limited range of cells

Question 19

What type of cells are adult stem cells?

Answer 19

Multipotent

Question 20

What are embryonic stem cells?

Answer 20

Cells obtained from embryos at an early stage of development

Question 21

How are embryonic stem cells obtained?

Answer 21

Embryos are created in labs using IVF.
Egg cells are fertilised by sperm outside the womb.
Once the embryos are approximately 4-5 days old stem cells are removed from them and the rest of the embryo is destroyed

Question 22

Why are embryonic stem cells good?

Answer 22

They can divide an unlimited number of times and develop into all types of body cells

Question 23

Why are embryonic stem cells bad?

Answer 23

Due to the ethical issues surrounding embryonic stem cell use

Question 24

What type of cells are embryonic stem cells?

Answer 24

Pluripotent

Question 25

What are induced pluripotent stem cells?

Answer 25

Cells that are created by scientists in the lab. The process involves ‘reprogramming’ adult body cells so that they become pluripotent.

Question 26

Explain the process of making induced pluripotent stem cells

Answer 26

1. the adult stem cells are made to express a series of transcription factors that are normally associated with pluripotent stem cells.
2. transcription factors can be introduced to the adult cells by infecting them with a specially modified virus. The virus has the genes coding for the transcription factors within its DNA.
3. when the virus infects the adult cells, these genes are passed into the adult’s cells DNA meaning that the cell is able to produce the transcription factors

Question 27

What are induced pluripotent stem cells useful for?

Answer 27

Research and medicine in the future