bmb 460 final exam - intro pptx

tophat questions and questions

what is a stem cell?

cell types which can divide and renew; be eventually differentiated into different cell lineages

can stem cells self-renew to recreate functional tissues?

yes

can stem cells be used to replace cells/tissues that have been damaged or lost to disease?

yes

what are the two properties of stem cells

they can make copies of themselves and become two or more other cell types

which of these is not a property of stem cells?

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A. stem cells can make copies of themselves

B. stem cells can become two or more other cell types

C. stem cells are found only in the embryo

C. stem cells are only found in the embryo

what differentiates different stem cell types?

how many other cell types they can become

what are the three stem cell types?

totipotent, multipotent, and pluripotent

totipotent cells

form all cell types in the body, including extra embryonic or placental cells (embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent)

pluripotent cells

can give rise to all of the cell types that make up the body; embryonic stem cells are considered pluripotent (post 8 cell divisions)

multipotent cells

can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells are cord blood stem cells are considered multipotent

up to the 8-cell stage, embryonic cells are what cell type

totipotent (can produce placenta and all cells of organism)

after the 8-cell stage, embryonic cells are considered

pluripotent (can produce all cells of adult organism but NOT the placenta)

cells of the inner cell mass are of what cell type

pluripotent (give rise to the fetus)

what is the name of a type of blastula cell (pluripotent), aka very early stage embryo

blastocyst

embryonic stem cells are what type of stem cell?

pluripotent

what are the three germ layers that make up the adult body?

mesoderm, ectoderm, endoderm

the inner cell mass isolated from the blastocyst (gives rise to the fetus) can differentiate into which germ layers?

mesoderm, endoderm, and ectoderm

external germ layer

ectoderm

middle germ layer

mesoderm

internal germ layer

endoderm

when do cells lose their pluripotency?

gastrulation stage

what is cell movements lead to the formation of 3 layers of cells called germ layers

gastrulation

when cells have reached the gastrula stage, can they be used for therapeutics?

no; they’ve received their specific mRNAs and can’t differentiate into anything different

what is the biggest source of embryonic stem cells?

in vitro fertilization (IVF) therapy

why can’t embryonic stem cells be used for research?

ethical issues and legal issues

what are benefits of human embryonic stem cells?

pluripotent cells provide max possibilities for developing therapeutics and understanding differentiation/development

what are drawbacks of using human embryonic stem cells?

unethical depending on beliefs, some states have banned human embryo research, and they can be difficult to grow and manipulate

why are adult stem cells necessary for the body?

some organs need a constant supply of cells (ex: GI tract, hair cells, etc.)

characteristics of adult stem cells

capable of self-renewal and differentiation, undifferentiated cells can continue dividing indefinitely but produce some daughter cells that undergo terminal differentiation, multipoint stem cells, can be unipotent stem cells (give rise to cells that differentiate into a single cell type)

benefits of using human adult stem cells

less ethical dilemmas, easier to differentiate a cell with limited potential (than one w unlimited), no risk of immune rejection

drawbacks of using adult stem cells

limited differentiation (multipotent vs. pluripotent), difficult to isolate, difficult to culture (ex: HSC can’t be cultured in vitro w/out losing SC character bc of differentiation)

which of these statements is correct?

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A. embryonic SC are isolated from cells in blastocyst at a very early stage embryo

B. inner mass cells become fetus while trophoblast becomes placenta

C. inner cell mass of blastocyst are multipotent

D. early stage embryo up to 8-cell stage is totipotent and can produce placenta and all cells of organism

A. B. and D.

What are the drawbacks of adult human stem cells? (select all)

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A. multipotent

B. often difficult to isolate

C. illegal in some states

D. ethical issues - depending on someone’s beliefs

E. difficult to culture

A. B. and E.

what is nuclear transfer?

inserting the nucleus of an already differentiated adult cell (ex: skin cell into donated egg that had its’ nucleus removed)

after nuclear transfer, what cell type is the cell stimulated to form?

blastocyst (ESC can be derived from here)

what famous experiment used nuclear transfer?

cloning of Dolly the sheep

what is transdifferentiation

conversion of one cell type to another

what is determination?

cell undergoes a self-perpetuating change of internal character, that distinguishes its progeny from other cells and commits it to a specialized course of development

what provided evidence that terminally differentiated chromatin from an adult can be reprogrammed to allow transdifferentiation?

Somatic Cell Nuclear Transfer (specific type of NT)

what are iPSCs?

a type of pluripotent stem cells that are particularly amenable to therapeutic uses

important features of iPSCs

can be made from any living person so they can be immune-matched (or DNA-matched) to any patient (reduces need for immune suppression)

can be made from any person, and used to model any disease

term for immune matched cells

“autologous”

term for unmatched immune cells

“allogenic”

how are iPSCs made?

skin cells (fibroblasts) or blood cells from adults are converted via __**reprogramming**__

how is the reprogramming process mediated?

via viruses or mRNAs that produce proteins involved in pluripotency

AND

with Yamanaka Factors

Rank these from highest to lowest degrees of SC potency

Multipotent, Pluripotent, Totipotent, Unipotent

Totipotent, Pluripotent, Multipotent, Unipotent

________ is the conversion of one cell type to another

transdifferentiation

which of these statements are correct?

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A. hematopoietic SC are found in the peripheral blood and bone marrow

B. ES cells are pluripotent cells derived from inner mass of blastocyst

C. skin cells (fibroblasts) or blood cells from adults are converted into iPSCs via transdifferentiation

D. Yamanaka factors are a group of TFs that play a vital role in the creation of iPSCs

E. Electric pulses cause the donor cell to split into equal halves during the process of somatic cell nuclear transfer

A. B. and D.