Vertebrate Development III

Question 1

Maternal factors in the ___1.___ region of the egg specify that region as prospective ___2.___, whereas maternal factors in the ___3.___ half of the egg specify that region as prospective ___4.___

Answer 1

1. animal
2. ectoderm
3. vegetal
4. endoderm

ways to remember — animals on the outside of this place and vegetables are inside the fridge

Question 2

Most of the developmentally important maternal products end up in the ___1.___ hemisphere of the ___2.___ egg

Answer 2

1. vegetal

2. mature

Question 3

The expression of developmentally important maternal mRNAs is regulated such that in most cases they are only translated after ___1.___ … to specify early polarity and initiate further development

Answer 3

1. fertilization

Question 4

T or F: the animal-vegetal axis of the egg is related to the antero-posterior axis of the tadpole, as the head will form from the animal region, but the axes of the tadpole and the fertilized egg are directly comparable

Answer 4

FALSE (the axes of the tadpole and the fertilized egg are NOT directly comparable)

Question 5

Which side of the animal region will form the head is not determined until the ___1.___ side of the embryo is specified, which does not happen until after ___2.___

Answer 5

1. dorsal

2. fertilization

Question 6

The precise position of the embryo’s antero-posterior axis depends on the specification of the ___1.___ axis

Answer 6

1. dorso-ventral

Question 7

T or F: Sperm entry can occur anywhere in the vegetal hemisphere, and it causes the outer layer of cytoplasm, the cortex, to loosen from the inner dense cytoplasm so that is able to move independently (cortical ___1.___ )

Answer 7

FALSE (animal hemisphere instead of vegetal hemisphere)

1. rotation

Question 8

___1.___ act as tracks for the directed movement of some maternal proteins and mRNAs from the vegetal pole to sites on the equator opposite the point of sperm entry

Answer 8

1. sub-cortical microtubules

Question 9

Cells that inherit these factors form ___1.___ structures, and the factors are called ___2.___ factors

Answer 9

1. dorsal

2. dorsalizing

Question 10

Local activation of ___1.___ signaling specifies the future dorsal side of the embryo

Answer 10

1. Wnt/beta-catenin

Question 11

The ___1.___ is induced in response to signals from another signaling center that arises in the ___2.___ region of the early ___3.___

Answer 11

1. Spemann Organizer
2. dorsal
3. blastula

Question 12

___1.___ or ___2.___ from the combined actions of ___3.___ , ___4.___ , ___5.___ , and other maternal factors present in the dorsal side of the vegetal region

Answer 12

1. Blastula Organizer
2. Nieuwkoop Center
3. Wnt-11
4. Wnt-5a
5. beta-catenin

Question 13

The ___1.___ sets the initial ___2.___ polarity

Answer 13

1. Nieuwkoop Center

2. dorso-ventral

Question 14

The ___1.___ of the Xenopus blastula makes clear the function of ___2.___

Answer 14

1. fate map

2. gastrulation

Question 15

T or F: Cells of the early Xenopus embryo do not yet have their fates determined and regulation is possible

Answer 15

TRUE

Question 16

___1.___ and ___2.___ are specified by ___3.___ , whereas mesoderm in induced from ___4.___ by signals from the ___5.___

Answer 16

1. Endoderm
2. ectoderm
3. maternal factors
4. ectoderm
5. vegetal region

Question 17

___1.___ induction occurs during a limited period in the blastula stage (it is one of the key events in vertebrate development as the ___2.___ itself is a source of essential signals for further development of the embryo)

Answer 17

1. & 2. mesoderm

Question 18

___1.___ gene expression is turned on at the ___2.___ transition

Answer 18

1. zygotic

2. mid-blastula

Question 19

Mesoderm-inducing and patterning signals are produced by the ___1.___ region, the ___2.___, and the ___3.___ mesoderm

Answer 19

1. vegetal
2. organizer
3. ventral

Question 20

The zygotic expression of mesoderm-inducing and patterning signals is activated by the combined actions of the ___1.___ ___2.___ and ___3.___ signaling

Answer 20

1. maternal
2. VegT
3. Wnt

Question 21

___1.___ has a global organizing function

Answer 21

1. The Spemann Organizer

Question 22

The Spemann Organizer is located at the ___1.___ lip of the ___2.___, which is the site where ___3.___ movements are initiated

Answer 22

1. dorsal
2. blastopore
3. gastrulation

Question 23

Signals from the organizer pattern the mesoderm ___1.___ by ___2.___ the effects of ___3.___ signals

Answer 23

1. dorso-ventrally
2. antagonizing
3. ventral

Question 24

The ___1.___ axis of the embryo emerges during ___2.___ and the ___3.___ is induced in the ectoderm

Answer 24

1. antero-posterior
2. gastrulation
3. neural plate

Question 25

The ___1.___ system is patterned along the ___2.___ axis by signals from the ___3.___

Answer 25

1. nervous
2. antero-posterior
3. mesoderm

Question 26

The final body emerges by the end of ___1.___ and ___2.___

Answer 26

1. gastrulation

2. neurulation