Stem Cells from Rich Notes

Question 1

What are two unique properties of stem cells?

Answer 1

self-renewal and differentiation

Question 2

What is a 16-32 cell zygote called? At what stage is it possible to see differentiation?

Answer 2

morula; blastocyst at day 4-5 post-fertilization when inner cell mass can be distinguished from trophectoderm

Question 3

What will the inner cell mass form, and what will the trophectoderm form? What does the inner cell mass become first?

Answer 3

embryo, placenta; three germ layers and germ cell lineage

Question 4

What are the three germ layers, and what are their derivatives?

Answer 4

ectoderm - skin and nervous system

mesoderm - vertebrae, muscle, genital ridges, and urinary system

endoderm - GI tract, liver, and lung, etc.

Question 5

What type of potency do zygotes at the 1 to 8 cell stage have? And what kinds of cells can they produce?

Answer 5

totipotency

cells of all tissue types

Question 6

What type of potency do cells have beyond the 8 cell stage?

The inner cell mass can differentiate into all the tissues of the body except for what?

Answer 6

pluripotency

extraembryonic membranes

Question 7

Some adult tissues have stem cells that can still differentiate in multiple cell types but are still restricted. Give an example.

Answer 7

Hematopoietic –> erythrocytes or lymphocytes

Question 8

Some adult tissues have stem cells that can only differentiate into a single cell type. Where do these committed precursors reside in the body?

Answer 8

skin, intestine, skeletal muscle, and testis

mnemonic: spells SIST

Question 9

What are 4 sources of stem cells?

Answer 9

> embryonic - pluripotent and can be propogated as cell lines
adult - either committed to specific lineage or multipotent; find in tissues with high rates of turnover (skin for ex.)
umbilical cord - multipotent hematopoietic stem cells
induced pluripotent - reprogrammed adult somatic cells

Question 10

What are 4 uses of embryonic stem cells?

Answer 10

> experiments to study development and gene regulation
drug discovery and testing
development of transgenic mouse models of disease
stem cell therapy

Question 11

Embryonic stem cells from black mice are grown in culture and the gene of interest is introduced into the another population of embryonic stem cells by using what? The colony is injected into a blastocyst of a white mouse and implanted into a foster mother. The pups turn out black and white. The black coat gene has been transmitted, so the mice are called what?

Answer 11

a plasmid; chimeras

Question 12

In a general sense, stem cell therapy using embryonic stem cells involves what 3 steps?

Answer 12

1. establishing an embryonic stem cell line
2. differentiating the embryonic stem cells to the cell type of interest
3. injecting it into a patient to treat a disease

Question 13

A nucleus is removed from a somatic cell. A nucleus is removed from an oocyte. The nucleus from the somatic cell is transferred into the oocyte cytoplasm. The oocyte is then stimulate to begin developing as an embryo. What is this process called?

Answer 13

somatic cell nuclear transfer

Question 14

Once the embryo that results from a somatic cell nuclear transfer reaches the blastocyst stage, the blastocyst is implanted in a mother and the resulting offspring is a clone of the individual who donated the somatic cell nucleus. What is this type of cloning?

Answer 14

reproductive

Question 15

The blastocyst that develops from a somatic cell nuclear transfer is used to make embryonic stem cells, which are differentiated and used to treat a patient. What is this type of cloning called? What problem does this type of cloning avoid?

Answer 15

therapeutic cloning

immune rejection since the embryonic stem cells are derived from the patient

Question 16

Human embryonic stem cells are derived from excess blastocysts that are created for what process?

Answer 16

in vitro fertilization

Question 17

What type of marker is used to find an adult stem cell? What is an example of adult stem cells being used as a treatment?

Answer 17

plasma membrane protein and antibody; injection of bone marrow stem cells into the heart after an MI

Question 18

What is an alternative to bone marrow transplantation?

Answer 18

hematopoietic stem cells obtained from umbilical cords

Question 19

What are three major concerns for stem cell research?

Answer 19

1. efficacy - needs to provide a benefit that outweighs any risk to the patient
2. safety - stem cells can form tumors…
3. immune rejection - normal for any type of transplant

Question 20

What two alternatives have been proposed to address the immune rejection issue with stem cell therapy? (besides immuno suppressive drugs)

Answer 20

1. genetic alteration of the donor stem cells to be compatible with the recipient
2. therapeutic cloning using somatic cells from the patient so that the stem cells will be compatible with patient’s own immune system

Question 21

What are 4 concerns of using embryonic stem cells?

Answer 21

1. proliferation without feeder layers (try to avoid other types of cells)
2. differentiation factors (factors to help direct cells toward 1 lineage)
3. full functional differentiation
4. ethical

Question 22

What are 3 concerns of using adult stem cells?

Answer 22

1. identification and isolation - hard to find, small percentage
2. differentiation - limited capacity to differentiate and proliferate
3. genetic defects - may contain same genetic defects as the cells causing the patient’s disease

Question 23

What do stem cells play an important role in?

Answer 23

normal maintenance of tissues and tissue repair after injury