Stem Cells

Question 1

What is a stem cell?

Answer 1

A primitive cell that can self-renew or give rise to more specialized cell types (differentiated)

Question 2

What does a stem cell typically produce?

Answer 2

one stem cell and one daughter cell

Question 3

What are the major characteristics of stem cells?

Answer 3

1. Not terminally differentiated
2. can divide without limit
3. Under slow divison
4. when divided = one stem cell characteristics, one with ability to differentiate

Question 4

What is totipotency (embryonic stem cell)?

Answer 4

Ability to give rise to all cells of an organism, including embryonic and extraembryonic tissues (ZYGOTE)

Question 5

What is Pluripotency (embryonic stem cell)?

Answer 5

Ability to give rise to all cells of the embryo and adult tissues (blastocyst)

Question 6

What is multipotency (adult/somatic stem cell)?

Answer 6

Ability to give rise to different cell types of a given lineage (blood cells, connective tissue)

Question 7

What are the tree main things multipotent stem cells can become?

Answer 7

the ectoderm, endoderm, and mesoderm

Question 8

What are founder stem cells?

Answer 8

(small -> large) always present in organ tissues and determine organ size through signaling

Question 9

What are transit amplifying cells?

Answer 9

Cells that divide frequently, giving one stem cell and one daughter cell with stem cell characteristics - > commited, # divisions finite

Question 10

What are the two ways stem cells are maintained?

Answer 10

Divisional and environmental asymmetry

Question 11

What is division asymmetry?

Answer 11

creates 2 cells, one with stem cell character. and one with factors that give it the ability to differentiate

Question 12

What is environmental asymmetry?

Answer 12

Makes 2 identical cells that environment may influece or alter one of the cells

Question 13

What is immortal strand hypothesis?

Answer 13

one stem cell has original strand of DNA preserved from stem cell, another gets newly synthesized strand

Question 14

Characteristics of embryonic stem cells?

Answer 14

1. derived from blastocyst
2. proliferate indefinitely
3. forms any body part

Question 15

What happens when embryonic stem cells are injected into an embryo at a later stage or into an adult ?

Answer 15

They fail to receive proper cues for proper differentation leading to tertomas.

Question 16

How are ES cells grown?

Answer 16

in vitro using mast cells from the blastocyst, irradiated with mouse fibroblast, growing cells

Question 17

What transcription factors are essential for establishment and maintenance of pluripotent stem cells in the embryo that embryonic stem cells express?

Answer 17

Nanog, Oct4, Sox2, FoxD3 (along with Cripto, GDF3 found in pluripotent)

Question 18

What and where are adult stem cells?

Answer 18

They are found in tissues and repond to demands of growth/repair. Strict population of genes expressed, meaning platicity is extremely low (compared to ES cells)

Question 19

Why are teratomas more rare in adult stem cell applications?

Answer 19

Because adult stem cells are multipotent and are very limited to what they can become, unlike ES cells.

Question 20

What can hematopoietic stem cells become and where are they derived from?

Answer 20

Derived from bone marrow, they can become blood components

Question 21

What can mesenchymal (stromal) stem cells become and where are they derived from?

Answer 21

they can become connective tissues and tissues and are derived from bone marrow

Question 22

What is cord blood?

Answer 22

an adult stem cell that is undifferentiated and need no gene manipulation. can be used to treat your own disease down the road

Question 23

what therapies can adult stem cells be used for?

Answer 23

regenerate neuronal cells post-stroke

Question 24

What are some major regenerative medicine issues/disadvantages for mature and early stem cells?

Answer 24

(Mature)
1. limited longevity
2. Difficult to find
3. Many unknowns
4. Multipotent
(Early)
1. Immune rejections
2. Difficult to control

Question 25

What is somatic cell nuclear transfer (SCNT)?

Answer 25

Nucleus is taken from somatic cell of patient and injected in to the oocyte of a donor replacing the oocyte nucleus CAUSES CLONING = BAD*

Question 26

What are the key determinants of ES cell character?

Answer 26

Gene regulatory proteins : Oct3/4, Sox2, Myc, KIf4

Question 27

What are alternative sources for human ES cells?

Answer 27

induced pluripotent stem cells (iPS)

somatic cell nuclear transfer

Question 28

Why are induced pluripotenstem cells (iPS) very bad?

Answer 28

They are replicated using viruses in recombinant DNA! therefore there is a much higher rate of tertomas than ES.