Stem cell

Question 1

1.

What are stem cells ?

Answer 1

• A stem cell is a cell that can divide (by mitosis) an unlimited number of times
• Each new cell (produced when a stem cell divides) has the potential to remain a stem cell or to develop into a specialised cell such as a blood cell or a muscle cell (by a process known as differentiation)

Question 2

What is potency ?

Answer 2

• The ability of stem cells to differentiate into more specialised cell types

Question 3

What are the three types of potency ?

Answer 3

• Totipotency
• Pluripotency
• Multipotency

Question 4

What is totipotency ?

Answer 4

• Totipotent stem cells are stem cells that can differentiate into any cell type found in an embryo , as well as extra-embryonic cells (cells that make up the placenta).

Question 5

What is pluripotent ?

Answer 5

• Pluripotent stem cells are embryonic stem cells that can differentiate into any cell type found in an embryo but are not able to differentiate into extra-embryonic cells.

Question 6

What is multipotent ?

Answer 6

• Multipotent stem cells are adult stem cells that have lost some of the potency associated with embryonic stem cells and are no longer pluripotent

Question 7

What type of stem cells are the ones found in the bone marrow ?

Answer 7

• The stem cells found in bone marrow are multipotent adult stem cells
• This means that they only differentiate into erythocytes (RBC),monocytes,neutophils and lymphocytes.

Question 8

What is erythropoiesis ?

Answer 8

• As red blood cells lack a nucleus, they cannot divide, meaning that new erythrocytes are constantly being formed from bone marrow stem cells in order to maintain the red blood cell count in the blood.
• During erythropoiesis, changes occur that adapt the structure of the original stem cell to enable it to function as an erythrocyte

Question 9

What stem cells do plants have ?

Answer 9

• Meristems

Question 10

What are the uses of stem cell research ?

Answer 10

• Due to their ability to differentiate into multiple cell types, stem cells have huge potential in the therapeutic treatment of disease
• The embryos used for research are often the waste (fertilised) embryos from in vitro fertilisation treatment
• This means these embryos have the potential to develop into human beings
• This is why many people have ethical objections to using them in research or medicine

Question 11

What is the issue with donating multipotent stem cells (bone marrow) ?

Answer 11

• However, if multipotent stem cells are being donated from one person to another they need to be a close match in terms of blood type and other body antigens
• There is a chance that the cells used are rejected by the patient’s immune system
• Ideally, the patient’s own adult stem cells are used to treat them, as there is a much lower chance of rejection

Question 12

What conditions can stem cells treat ?

Answer 12

• Alzheimers disease
• Parkinsons
• Spinal injuries
• Blood disease
• Type 1 diabetes
• Heart attack

Question 13

What are the benefits of stem cells ?

Answer 13

• Great potential to treat a wide-variety of diseases from diabetes and paralysis
• Organs developed from a patients own a stem cells reduces the risk of organ rejection and the need to wait for an organ donation.
• Adult stem cells are already used sucessfully in a variety of treatments acting as proof of benefits.