20.2

Question 1

cell divison

Answer 1

transforms single celled zygote into a multicellular organism

Question 2

early embryo cell cycle

Answer 2

“cell cleavage”
-occurs rapidly
-no cell growth
-no G1 or G2

Question 3

later embryo cell cycle

Answer 3

takes longer
Exhibits G1 and G2 (cell growth)

Question 4

differentiation

Answer 4

productions of specialized (differential) cells
-differentiated cells arise from the division of undifferentiated stem cells
*1 daughter cells gives rise to cells that differentiate
* other replaces the stem cell (self-renewal)

Question 5

differentiation depends on changes in gene expression

Answer 5

involves progressive restriction of the number of fates the cells within lineage can adopt
=> this occurs over multiple cell

Question 6

stem cell potency restricts possible cell fates

Answer 6

totipotent
pluripotent
multipotent
unipotent

Question 7

totipotent

Answer 7

form all tissues of organism, plus the extraembryonic tissues
ex: zygote

Question 8

pluripotent

Answer 8

form all tissues of the organism
cannot form extraembryonic tissues
ex: embryonic stem cells from blastocyst inner cell mass (blue)

Question 9

multipotent

Answer 9

can only form certain cell types
ex: adult stem cells (muscle, nerve, adipocyte)

Question 10

unipotent

Answer 10

can only form one cell type
ex: spermatogonia (germ) stem cells