Stem Cells and Applications

Question 1

Totipotency vs pluripotency

Answer 1

Totipotent- Embryonic stem cell, gives rise to all cell times including extraembryonic (placenta). Found in zygote
Pluripotent- Embryonic stem cell, gives rise to all cells of the embryo and adult tissues. Found in blastocyst

Question 2

Divisional asymmetry

Answer 2

Division gives rise to two cells, one stem cell and one with factors that give it ability to differentiate

Question 3

Environmental asymmetry

Answer 3

Division makes two identical cells but environment may alter one of them

Question 4

Immortal strand hypothesis

Answer 4

Some tissues stem cells selectively retain original DNA after division. One cell gets original DNA and the other gets newly synthesized DNA. Cell with original DNA with remain stem cell

Question 5

What may happen if embryonic stem cell is injected into embryo at later stage or into adult

Answer 5

They fail to receive appropriate sequence of cues for proper differentiation and may become a tumor or teratomas

Question 6

Cell type produced from retinoic acid + insulin, thyroid hormone

Answer 6

Adipose

Question 7

Cell type produced from retinoic acid alone

Answer 7

Neuron

Question 8

Cell type produced from MCSF, IL-3, IL-1

Answer 8

Macrophage

Question 9

Cell type produced from cAMP, retinoic acid

Answer 9

Smooth muscle

Question 10

Cell type produced from Fibroblast GF, FGF2, EGF, platelet derived GF

Answer 10

Astrocytes, oligodendrocytes

Question 11

Mesenchymal stem cells may produce

Answer 11

Connective tissues, tissues

Question 12

Hematopoietic stem cells found where

Answer 12

Cord blood, bone marrow, peripheral blood

Question 13

Mesenchymal stem cells found where

Answer 13

Whartons jelly, bone marrow, adipose, tooth pulp

Question 14

Can adult stem cells regenerate neuronal cells

Answer 14

Yes

Question 15

What is a major problem with adult stem cell therapies

Answer 15

Immune rejection, if genetically different, grafted cells can be rejected by host

Question 16

What is somatic cell nuclear transfer

Answer 16

Nucleus is taken from a somatic cell and injected into the oocyte of a donor, replacing the oocyte nucleus. Blastocyst is generated and ES cells isolated

Question 17

iPS induced pluripotent stem cells

Answer 17

4 Gene regulatory factors injected into fibroblast- Oct3/4, Sox2, Myc and Klf4.
When injected into fibroblast they become ES like cells and can differentiate into other cell types
-Low yield and not identical to ES cells
-Very high potential for teratoma formation

Question 18

Challenges with SCNT

Answer 18

Inefficient, may need hundreds of oocytes

Technically demanding, needs to be available in many or all hospitals