259b stem cells

Question 1

stem cell traits

Answer 1

self-renewal - regenerates itself

potency - can give rise to different types of cells

Question 2

asymmetric vs symmetric stem cell division

Answer 2

asymmetric is one identical daughter cell and one differentiated cell

symmetric is two identical stem cells

Question 3

types of stem cells

Answer 3

toti - zygote

pluripotent - ES, blastocysts (ICM) from 5 day old embryo, give rise to most tissues, adult stem cells

multipotent - HSC, committed to cells with a specific fxn

Question 4

where do stem cells come from?

Answer 4

ICM of blastocyst

Question 5

patient specific ES cells (cloning), nuclear reprogramming and problems with reproductive cloning?

Answer 5

make ES with patients own DNA

nuclear reprogramming: remove DNA from egg, inject DNA from donor skin cells, coax into developing

problems: nuclear cloning is not efficient, doesn’t product a normal individual when used in reproduction

Question 6

therapeutic nuclear cloning

Answer 6

goal is to make compatible ES for therapy by fixing mutation (either from unaffected tissue for somatic mutation OR fixing bad gene for germline mutation)

use blood cells and manipulate into other cell types (change from multipotent –> pluripotent)

Question 7

iPS (induced pluripotent stem cell)

Answer 7

take a differentiated cell and revert to a stem cell

use fibroblasts and give embryonic genes or acidic environment –> pluripotent stem cells

Question 8

what is the danger of giving patients undifferentiated stem cells?

Answer 8

can form tumors (teratomas)

Question 9

autologous vs allogeneic

Answer 9

autologous - same person

allogeneic - different people

Question 10

plasticity

Answer 10

ability of tissue-restricted stem cell (adult stem cell) to give rise to differentiated cell types of other tissue types

Question 11

hematopoiesis

Answer 11

formation of cellular components in blood

Question 12

fetal hematopoiesis

Answer 12

Fetal erythropoiesis occurs in:  
Yolk sac (3–8 weeks)
Liver (6 weeks–birth)
Spleen (10–28 weeks)
Bone marrow (18 weeks to adult)

Young Liver Synthesizes Blood

hemangioblast are early RBC stem cell

HSC are derived from hemogenic endothelium
both are from mesoderm origin

Question 13

hemoglobin development

Answer 13

Fetal hemoglobin (HbF) = α2γ2.
Adult hemoglobin (HbA) = α2β2

From fetal to adult hemoglobin:
Alpha Always; Gamma Goes, Becomes Beta.

HbF has higher affinity for oxygen due to less avid binding of 2,3-BPG. This allows HbF to extract oxygen from (HbA) maternal hemoglobin across the placenta.

Question 14

what does common myeloid progenitor come from? what does it make?

Answer 14

multipotent progenitor (From HSC)

RBCs, monocytes, granulocytes, platelets

Question 15

what does common lymphoid progenitor come from? what does it make?

Answer 15

multipotent progenitor (From HSC)

B/T/NK cells