Cell Differentiation and Gene Expression

Question 1

What are Totipotent stem cells?

Answer 1

Cells that can differentiate into every type of cell in the body. The ZYGOTE is the only type of totipotent stem cell

Question 2

What are Pluripotent stem cells?

Answer 2

Cells that can differentiate into most, but not all types of cells. Embryonic stem cells are examples of pluripotent stem cells

Question 3

What are Multipotent Stem cells?

Answer 3

Cells that can differentiate into a limited number of cell types. Hematopoietic and Mesenchymal stem cells are examples of multipotent stem cells

Question 4

What are Unipotent Stem cells?

Answer 4

Cells that form one type of differentiated cell only. Spermatological stem cells and dermatocytes are examples of unipotent stem cells

Question 5

What are the two types of Stem cell division and their definition?

Answer 5

Asymmetric Division - a stem cell produces one differentiated and one stem cell

Symmetric Division - a stem cell produces two differentiated cells OR two stem cells

The symmetric division is the most common type of SC division

Question 6

What types of Stem Cells are embryonic stem cells and adult stem cells?

Answer 6

EMBRYONIC - pluripotent or totipotent

ADULT - multipotent

Question 7

What are Stem Cell Niches?

Answer 7

Stem Cell Niches are special supportive microenvironments that tissue-specific stem cells are maintained

Question 8

What are the stem cell niches/microenvironments supported by?

Answer 8

Stem Cell Niches are supported by the following:
-Secreted factors
-Inflammation and Scarring
-Extracellular matrix
-Physical factors
-Hypoxia and Metabolism
-Cellular components

Question 9

What are the two types of stem cells found in the bone marrow?

Answer 9

-Hematopoietic stem cells
-Mesenchymal stem cells

Question 10

What is the difference between Hematopoietic stem cells and Mesenchymal stem cells?

Answer 10

HSCs are multipotent stem cells anchored to fibroblast-like osteoclasts of the marrow of long bones. They produce all blood cells and some immune system cells. They regularly self-renew

MSC are also multipotent stem cells found in the bone marrow. They do not self-renew regularly and they give rise to CHONDROCYTES, OSETOBLASTS AND MYOCYTES AND ADIPOCYTES

Question 11

What are progenitor stem cells?

Answer 11

They are stem cells that have the tendency to differentiate into one specific type of cell

Question 12

What is the difference between Lymphoid progenitor cells and Myeloid progenitor cells?

Answer 12

They are both multipotent stem cells and they further differentiate into Lymphoid and Myeloid cells. They are both described as oligopotent progenitors.

They have a low tendency to differentiate and even when they do they give rise to very specific cells within their lineage.

Question 13

What is cell differentiation regulation?

Answer 13

Cells differentiate through differential gene expression. The types and number of proteins a cell generates help to determine how a cell
differentiates

Question 14

What are house-keeping genes?

Answer 14

A gene expressed in all or nearly all cell types, e.g. tubulin

Question 15

What are luxury genes?

Answer 15

A gene expressed in only one or a few cell types

Question 16

What are Pioneer factors?

Answer 16

Pioneer factors are transcription factors that can bind to condensed chromatin, remodel it and initiate cell fate and differentiation. They are master regulators

Question 17

What is DNA methylation?

Answer 17

An epigenetic mechanism that occurs by the addition of a methyl (CH3) group to
DNA. The methyl adds to the 5-carbon on the CYTOSINE ring resulting in 5-methylcytosine (5mC)

Question 18

What is Somatic Cell Nuclear Transfer (SCNT)?

Answer 18

Artificial removal of the nucleus of a differentiated somatic cell and placing the nucleus into a denucleated egg cell

Question 18

What is Somatic Cell Nuclear Transfer (SCNT)?

Answer 18

Artificial removal of the nucleus of a differentiated somatic cell and placing the nucleus into a denucleated egg cell

side note: Dolly the Sheep

Question 19

What are Induced Pluripotent Stem Cells?

Answer 19

Pluripotent stem cells are artificially produced from somatic cells and they can produce all the cells of an organism.

The cells are exposed to FOUR transcription factors [OCT4, SOX2, KLF4 and c-MYC) - Yamanaka and Takashi

Question 20

Applications of iPSC

Answer 20

-Gene therapy
-Regenerative medicine
-Model disease and drug screening