Stem Cells

Question 1

What is the differentiation pathway for a stem cell? Note this is a broad overview, nothing specific.

Answer 1

Stem cell -> Committed Cell -> Differentiated Cell

Question 2

What are the 4 characteristics of stem cells?

Answer 2

• Not terminally differentiated
• Can divide without limit
• Undergo slow division
• When they divide, they give rise to 1 cell with stem cell characteristics and the other with the ability to differentiate

Question 3

Adult stem cells are _____ _____

Answer 3

Tissue specific

Question 4

Define Totipotency. Give an example.

Answer 4

Ability to give rise to all cells of an organism. This includes embryonic and extraembryonic tissues (PLACENTA).

Example is a ZYGOTE

Question 5

Define Pluripotent. Give an example and where it was obtained from.

Answer 5

Ability to give rise to all cells of the embryo and subsequently adult tissues.

Example is Embryonic stem cells from the blastocyst

Question 6

Define Multipotency. Give an example.

Answer 6

Ability to give rise to different cells types of a given lineage.

Example is adult stem cells. Can be tissue or somatic stem cells as well.

Question 7

What kinds of stem cells are inner mass cells? Where are these found?

Answer 7

Pluripotent stem cells

Obtained from blastocysts

Question 8

What are founder stem cells?

Answer 8

Determine the proportions of body parts because they have a fixed number of founder cells that have a fixed number of divisions.

Question 9

What are transit amplifying cells?

Answer 9

Cells that divide frequently.

After they leave the basal layer they transit from a cell with stem cell characteristics to a committed cell, and eventually to a terminally differentiated cell.

These cells have a limited number of divisions.

Question 10

What are the 2 theories for maintaining the stem cell population?

Answer 10

Divisional Asymmetry- Asymmetric division creates 2 cells, one with stem cell characteristics and the other with factors that allow it to differentiate

Environmental Asymmetry- Division makes 2 identical cells but environment may influence/alter 1 cell

Question 11

What is the immortal strand hypothesis?

Answer 11

Some stem cells retain their original DNA as a way to prevent genetic errors in stem cells. The daughter cell will retain stem cell characteristics, while the other cells become transit amplifying (committed) cells

Question 12

What happens if you inject an embryonic stem cell back into an embryo at a later stage or into an adult and it fails to receive the appropriate sequence of cues for proper differentiation?

Answer 12

A tumor will develop

Question 13

Embryonic stem cells give rise to ______

Answer 13

Teratomas

Question 14

How do embryonic stem cells give rise to teratomas?

Answer 14

ES cells are incapable of generating a body plan, therefore when they differentiate they lack organization and end up differentiating into a wide range of tissues.

Question 15

_____, ____, ____,. ___, ___, and ____ ____ form when ES cells are inhected into host animals

Answer 15

Cartilage, bone, skin, nerves, gut, and respiratory lining

Question 16

What 4 transcription factors are important for establishing and maintaining pluripotent stem cells in the embryo?

Answer 16

Nanog
Oct4
Sox2
FoxD3

Question 17

What are the 3 hematopoietic cells that stem cells can become?

HSCs- Hematopoietic stem cells

Answer 17

Platelets
RBCs
WBCs

Question 18

What are the 7 mesenchymal connective tissues that stem cells can become?

MSCs- Mesenchymal stem cells

Answer 18

Bone tissue
Cartilage tissue
Fat tissue
Heart tissue
Liver tissue
Muscle tissue
Nerve tissue

Question 19

What kind of stem cells come from cord blood?

Answer 19

Adult stem cells

Question 20

What are 2 ways to obtain pluripotent stem cells for the patient?

Answer 20

Patient derived- Induced Pluripotent stem cells (iPS)

Non patient derived- ES

Question 21

What are 2 ways to obtain adult stem cells for the patient? What kind of cells can these methods be used to obtain?

Answer 21

Bone marrow derived mesenchymal stem cells- transplant

Adipose derived mesenchymal stem cells- liposuction

Both of these techniques can be used to regenerate neuronal cells

Question 22

What are the limitations for the use of adult stem cells?

Answer 22

Immune rejection

Question 23

Describe the Somatic Cell Nuclear Transfer (SCNT) process used to obtain ES cells. What does this method solve in terms of limitations?

Answer 23

Nucleus is taken from somatic cells of the patient and injected into an oocyte of a donor replacing the oocyte nucleus. A blastocyst is generated from this hybrid oocyte and ES cells are isolated.

This solves tissue rejection problems because the cells express the patient’s genes.

Question 24

Describe the Induced Pluripotent Stem Cell (iPS) process. What is this process have a very high potential for treating?

Answer 24

Fertilization yields a zygote, which is totipotent. This zygote forms a blastocyst that contains inner mass cells of pluripotent stem cells. These inner mass cells are taken from the blastocyst and cultured to form embryonic stem cells.

Very high potential for treating teratomas.

Question 25

How did Dolly the sheep get cloned? Hint: which process did they use?

Answer 25

SCNT