Stem Cells

Question 1

What are stem cells?

Answer 1

Stem cells are unspecialised cells

Question 2

What are stem cells able to do?

Answer 2

Stem cells are able to differentiate into a diverse range of specialised cells

Question 3

Types of stem cells

Answer 3

Embryonic and Adult Tissue

Question 4

Where do embryonic stem cells come from?

Answer 4

Embryonic stem cells are derived from a 4-5 day old embryo (blastocyst)

Question 5

What are embryonic stem cells able to do?

Answer 5

Embryonic stem cells are able to differentiate into all types of cells that make up an organism (pluripotent)

Question 6

Where do adult tissue stem cells come from?

Answer 6

Adult tissue stem cells are found in small numbers in the tissue and organs of adults and children

Question 7

What are adult tissue stem cells able to do?

Answer 7

Adult tissue stem cells are able to differentiate into a limited number of cell types that are closely related to the nearby tissue (multipotent)

Question 8

Selective gene expression

Answer 8

Differentiated cells only express the genes that code for the proteins specific to the workings of that particular cell

Question 9

How does selective gene expression work?

Answer 9

The genes that don’t code for the proteins needed are turned off and the genes that are needed are turned on

Question 10

What are somatic cells?

Answer 10

Somatic cells are differentiated cells that form the different types of body tissue that exist

Question 11

How do somatic cells divide?

Answer 11

Somatic cells divide by mitosis for growth and repair

Question 12

Examples of somatic cells

Answer 12

Red blood cell and smooth muscle cell

Question 13

What are germline cells?

Answer 13

Germline cells include the gametes and the cells that produce the gametes

Question 14

How do germline cells divide?

Answer 14

Germline cells divide by mitosis. Gamete mother cells divide by meiosis to produce gametes

Question 15

Examples of germline cells

Answer 15

Sperm and eggs

Question 16

Germline mutations

Answer 16

Mutations in germline cells are passed on to offspring

Question 17

Somatic mutations

Answer 17

Mutations in somatic cells are not passed on to offspring

Question 18

What is a tumour?

Answer 18

A mass uncontrollable cell division

Question 19

What is a haploid?

Answer 19

A haploid is a cell containing 1 set of chromosomes (23)

Question 20

What is a diploid?

Answer 20

A diploid is a cell containing two sets of chromosomes (46)

Question 21

What is mitosis?

Answer 21

Mitosis is the process of cell division where 2 identical diploids are produced

Question 22

What is meiosis?

Answer 22

Meiosis is the process of cell division where 4 identical haploids are produced

Question 23

Therapeutic uses of stem cells

Answer 23

• Treat leukimia
• Make new bone cells
• Nerve cells to heal spinal cord injuries
• Taken from someone with heart disease to be turned into heart tissue
• Stem cell grafts for cornea repair
• Study diseases
• Drug testing
• Trachea (windpipe) transplant

Question 24

What are cancer cells?

Answer 24

They are cells that do not respond normally to regulatory signals and divide excessively to produce a mass of abnormal cells

Question 25

Benign tumour

Answer 25

Cancer cells continue to reproduce a mass of abnormal cells

Question 26

Malignant tumour

Answer 26

Lose molecules on their surface that would normally hold them in place and can therefore be detached from their neighbours, causing the cells to spread