PGC

Question 1

In mammals, a few cells in the pre-embryonic stage are induced by ___________ to become germ cells.

Answer 1

signal transduction of neighboring cells

Question 2

The beginning or first discernible indication of an organ or structure is called ___________.

Answer 2

primordium (anlage, rudiment)

Question 3

Any biological cell that gives rise to the gametes of an organism that reproduces sexually is termed a _____.

Answer 3

Germ cell

Question 4

Progenitor cells that give rise to gametes are referred to as _____.

Answer 4

Primordial germ cell

Question 5

Germ cells that still have to reach the gonads are _____, ______, or _____.

Answer 5

primordial germ cells, precursor germ cells, gonocytes

Question 6

Characteristically, germ cells divide repeatedly on their way through the __________ and into the developing __________.

Answer 6

gut; gonads

Question 7

During gastrulation, germ cell precursors migrate through the __________, which forms the __________, and from there to the __________.

Answer 7

posterior endoderm; hind gut; genital ridge

Question 8

The site of the developing gonads is known as the __________.

Answer 8

genital ridge

Question 9

What are the two main mechanisms of germline establishment?

Answer 9

Preformation (segregation) and Epigenesis (recreation)

Question 10

In __________, germ cell determinants (germ plasm) are set aside before or at fertilization and remain segregated throughout the organism’s life.

Answer 10

Preformation

Question 11

In __________, primordial germ cells are generated during development.

Answer 11

Epigenesis

Question 12

Which method of germline establishment is seen in all mammals?

Answer 12

Epigenesis

Question 13

Germ cells are set aside before other cell types in _____

Answer 13

Epigenesis

Question 14

Primordial germ cells are _____ (size), ______ (shape) sex cells visible among ________ of the umbilical vesicle (yolk sac) near the origin of the _______.

Answer 14

large, spherical; endodermal cells; allantois

Question 15

During embryonic folding, the __________ part of the ______ is incorporated into the embryo.

Answer 15

dorsal part of the umbilical vesicle

Question 16

PGCs are the common origin of __________ and __________ and thus represent _____.

Answer 16

spermatozoa; oocytes; germline ancestors

Question 17

Primordial germ cells are __________ (diploid/haploid) and recognized in the __________ during the __________ week.

Answer 17

diploid; epiblast; second

Question 18

In the ______ week, PGCs migrate from the __________ into the __________ and collect near the exit of the __________.

Answer 18

3rd week; epiblast; yolk sac; allantois

Question 19

PGCs wander amoebically from epiblast into the yolk sac in the 3rd week to become _____ lying in the ____ and ______ of the ______

Answer 19

Extraembryonal; endoderm and mesoderm of the yolk sac wall

Question 20

During the _____ week, PGCs begin to migrate from the ____ toward the __________ and arrive there by the end of the __________ week.

Answer 20

4th week; yolk sac; developing gonads; fifth

Question 21

Mitotic divisions of PGCs occur during their __________ and after they arrive at the __________.

Answer 21

migration; genital ridges

Question 22

In preparation for fertilization, germ cells undergo ______

Answer 22

Gametogenesis

Question 23

What two processes make up gametogenesis?

Answer 23

Meiosis and Cytodifferentiation

Question 24

Meiosis __________, while cytodifferentiation __________ respectively (functions)

Answer 24

reduces chromosome number; completes cell maturation

Question 25

______ and _____ lead to movement of PGCs back to embryo between week ____ and ____

Answer 25

Cranio-caudal curvature and lateral folding of embryo; Week 4 and 6

Question 26

During migration as embryo folding occurs, PGCs travel along the __________ of the ______ to the __________ and move along the ______ to the _____ and _____.

Answer 26

dorsal mesentery of the hindgut to the gonadal ridges; yolk sac wall to the vitelline and rectal wall

Question 27

After crossing the ______, PGCs colonize the __________.

Answer 27

dorsal mesentery, gonadal ridge

Question 28

During the _______ week, PGCs enter the underlying __________ and are incorporated into the __________.

Answer 28

6th week; mesenchyme; gonadal cords

Question 29

The genes that regulate PGC migration include __________, __________, and __________.

Answer 29

Stella; Fragilis; BMP-4

Question 30

In males, primordial germ cells form __________.

Answer 30

spermatogonia

Question 31

In females, primordial germ cells form __________.

Answer 31

oogonia

Question 32

Some of the oogonia arrest in __________ of __________ to become __________.

Answer 32

prophase; meiosis I; primary oocytes

Question 33

Gametes are derived from ______ formed in the __________ during the __________ week.

Answer 33

primordial germ cells; epiblast; second

Question 34

PGCs later migrate from the epiblast to the wall of the __________.

Answer 34

yolk sac

Question 35

Differentiation of PGCs into oogonia begins shortly after their arrival in the __________.

Answer 35

ovary

Question 36

By the __________ month, some oogonia give rise to primary oocytes that enter _____ of ____.

Answer 36

third month; prophase of meiosis I

Question 37

The prophase of meiosis I in oocytes may last __________ or more years and finishes when _______.

Answer 37

40; the cell begins its final maturation

Question 38

During prophase arrest, the primary oocyte remains __________ (diploid/haploid).

Answer 38

diploid

Question 39

Pluripotency in PGCs may be maintained by __________ modifications that suppress __________ programs.

Answer 39

epigenetic; somatic differentiation

Question 40

Transformation of primordial germ cells may lead to __________.

Answer 40

germ cell tumour

Question 41

Primordial germ cells are termed the __________ of the sex cells.

Answer 41

progenitors or ancestors

Question 42

Between the ____ and _____ week, _____ and ______ causes PGCs to move back into the __________.

Answer 42

4th and 6th week; cranio-caudal curvature and lateral folding of the embryo; embryo

Question 43

A cell that can produce only one cell type, its own, but retains the property of self-renewal?

Answer 43

Unipotent

Question 44

A cell that can develop into more than one cell type, but only within a certain lineage or tissue family?

Answer 44

Multipotent

Question 45

A cell that can give rise to all cell types of the body except extra-embryonic tissues?

Answer 45

Pluripotent

Question 46

A cell that can develop into all cell types, including extra-embryonic tissues such as the placenta?

Answer 46

Totipotent

Question 47

A pluripotent cell derived from the inner cell mass (cytotrophoblast) of the blastocyst that can give rise to virtually all cell types of the body?

Answer 47

Embryonic stem cell

Question 48

A pluripotent cell derived from primordial germ cells in the embryo that shares many properties with embryonic stem cells?

Answer 48

Embryonic germ cell