L11

Question 1

in the xenopus life cycle, there is no _______, or ____ and _____ phase

Answer 1

gap
G1
G2

Question 2

Xenopus eggs contain a large pool of _______ mRNAs and proteins

Answer 2

maternal

Question 3

X. during cleavage stages, _______ are synthesized from maternal mRNAs

Answer 3

new proteins

Question 4

during the first 12 divisions of xenopus, there is very little _______

Answer 4

transcription

Question 5

X. if you block protein synthesis, what happens?

Answer 5

blastula stops dividing

Question 6

X. sox17b and hbox18 are examples of what

Answer 6

transcription factors

Question 7

when placed in a neutral environment, animal cells express _______ genes and vegetal cells express _______ genes. they are specified to these fates

Answer 7

ectodermic

endodermic

Question 8

ectodermic genes go on to form what

Answer 8

epidermis, CNS, neural crest

Question 9

endodermic genes go on to form what

Answer 9

internal organs, GIT, respiratory system

Question 10

all metzoans have _______ germ layers

Answer 10

3

Question 11

the vegetal pole can ________ cells from the animal pole to become ________

Answer 11

instruct
mesodermic

Question 12

the _______ have the capacity to become mesodermic

Answer 12

animal cap cells

Question 13

if you recombine the animal cap with dorsal subsets, the result is mainly _____ genes

Answer 13

dorsal

Question 14

if you recombine the animal cap with the ventral subset, what happens?

Answer 14

vegetal pole tells them which type of mesoderm to become

Question 15

what are mesodermic marker genes?

Answer 15

secreted factors that can pass through small pores

Question 16

prospective ectoderm and endoderm are specified by ________

Answer 16

maternal factors

Question 17

3 germ layers and what they entail

Answer 17

ectoderm - skin and NS
endoderm - internal organs
mesoderm - kidney, blood, muscle, notocord

Question 18

characteristics of mesoderm inducers in Xenopus

secreted _________
cells from the _________ form mesoderm if exposed to the inducer
may induce different type of mesoderm along the _________ axis
expressed in the _________ at early blastula stage

Answer 18

proteins
animal cap
D/V
vegetal pole

Question 19

Vg1 is a member of the _____ superfamily of growth factors. its RNA is expressed early during _______ and is localized at the ________ of the oocyte

Answer 19

TFGbeta
oogenesis
vegetal cortex

Question 20

knock-down only reduces _________

Answer 20

mesoderm induction

Question 21

Vg1 is only expressed in the _______ side of the embryo

Answer 21

dorsal

Question 22

egT is an _______ factor - it is not secreted

Answer 22

intrinsic

Question 23

VegT is a ___________ factor, which is _____ expressed in all the ________ half of the embryo

Answer 23

transcription
maternally
vegetal

Question 24

maternal VegT induces _______ expression of ______ ligands - they are called Xnrs in xenopus

Answer 24

zygotic

nodal

Question 25

nodal goes from _____ to ______ from ventral to dorsal

Answer 25

low high

Question 26

the ______ form of smad2 is the active form of smad2

Answer 26

phosphorylated

Question 27

Nodal signalling is active at the right stage for ___________ induction

Answer 27

mesoderm

Question 28

TGFbeta is expressed in a lot of what

Answer 28

cancer

Question 29

SB505124 and SU5402 are what

Answer 29

an ATP analog

Question 30

inhibitin Nodal signalling causes loss of ________ is Xenopus embryo

Answer 30

mesoderm

Question 31

nodal signalling is required for ____________ gene expression

Answer 31

endodermic

Question 32

what are some roles of FGF signalling in mesoderm specification?

Answer 32

docking site for FH2 containing proteins MAP kinase pathway signals receptors that are tyrosine kinases

Question 33

the MAP kinase pathway is activated in the _________ during __________

Answer 33

marginal zone gastrulation

Question 34

nodal induces ______ in the cells overlying the ______

Answer 34

mesoderm endoderm

Question 35

the Spemann's organizer has ______ and ______ inhibitors

Answer 35

BMP wnts

Question 36

the roles of the spemann's organizer during development are as follows: - limit _____ signalds in the mesoderm - inhibit ____ signalling in the _____ to induce the neuro-ectoderm - contribute to _______ mesoderm

Answer 36

verntral BMP ectoderm axial

Question 37

the Spemann organizer is a _________ structure situated above the _________ in the ______ stage of amphibian embryos

Answer 37

multicellular blastopore lip gastrula

Question 38

the spemann organizer secretes ___________ and ________ inhibitors

Answer 38

canonical Wnt BMP

Question 39

when transplanted to the opposite site of an embryo, the spemann organizer can induce an ___________ neural plate and a _____ axis

Answer 39

ectopic secondary

Question 40

the Nieuwkoop centre and the Spemann organizer both give rise to _______ axis when grafted in the ____ side

Answer 40

secondary ventral

Question 41

the ectoderm and endoderm are ______ specified, but the mesoderm is induced post _______

Answer 41

maternally MBT

Question 42

the __________ induces the formation of the Spemann organizer

Answer 42

Nieuwkoop centre

Question 43

the spemann organizer limits ventral signals in the _______ and is necessary for the induction of ___________

Answer 43

mesoderm neural fate