Exam 2 prs Flashcards by Ashley Smith

Drosophila embryos undergo cleavage in a rather unique way. Which of the following terms can be used to describe Drosophila cleavage?

A. Superficial
B. Holoblastic
C. Rotational
D. Meroblastic
A &amp; D
A, B, &amp; D

A and D

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What does the Zelda protein regulate during Drosophila mid-blastula transition?

Gene activation
Cell division
Cellularization
Chromatin

gene activation

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The location of which cellular component of the oocyte determines first the anterior-posterior, then the dorsal-ventral axis of the Drosophila embryo?

Centrosomes
Nucleus
Endoplasmic reticulum
Mitochondria

nucleus

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After Dorsal protein is localized to the nucleus, how does it function to specify cell fates? As a ___

Morphogen
Signaling molecule
Transcription factor
A &amp; B
A &amp; C

morphogen and transcription factor

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The Dorsal protein is expressed uniformly along the dorsal-ventral axis. How does it act as a morphogen? Control of ___

Nuclear localization
Extracellular matrix composition
Receptor availability
Ligand degradation

nuclear localiztion

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During early cleavage, the Drosophila embryo is called the ___

Syncytial blastoderm
Blastula
Cellular blastoderm
Gastrula

syntical blastoderm

Syncytial blastoderm refers to the fact that many nuclei share a common cytoplasm.

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After cell cycle 13, the Drosophila embryo is called the ___

Syncytial blastoderm
Blastula
Cellular blastoderm
Gastrula

C. After cellularization, the embryo is referred to as a Cellular blastoderm to reflect the change from a syncytium to individual cells.

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Based on the information about Zelda, it is most likely a(n) ___________________.

Phosphatase
Ubiquitinase
Transcription factor
Ligand
Kinase

transcription factor

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Which protein degrades maternal RNAs during Drosophila MZT?

Hodor
Zelda
Smaug
Harry Potter

Smaug

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Which protein activates zygotic genes during Drosophila MZT?

Hodor
Zelda
Smaug
Harry Potter

Zelda

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Oskar and bicoid mRNAs are localized within the developing oocyte as a result of which cellular component?

Motor proteins
Mitochondria
Microtubules
A &amp; B
A &amp; C

motor proteins and microtubules

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Which transcription factor is responsible for specifying the anterior region of the Drosophila embryo?

Caudal
Bicoid
Zelda
Smaug

bicoid

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Caudal mRNA is equally distributed across the embryos anterior-posterior axis, yet Caudal protein concentration is high in the posterior and low in the anterior. This occurs because Bicoid protein__________.

Is an enzyme that adds a methyl group to Caudal protein
Acts to repress translation of Caudal protein
Binds Dynein and thus keeps Caudal protein from binding Dynein
Binds Kinesin and thus keeps Caudal mRNA from binding Kinesin

bicoid represses Caudal translation in the anterior

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What is the basis of control of expression of the even-skipped gene?

Protein modification
Transcriptional regulation
mRNA localization
mRNA degradation

transcription regulation

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Drosophila segmentation patterns are initiated during the syncytial blastoderm stage. Which type of factor maintains the segments after cellularization?

Transcription factors
Cytoskeletal factors
Ribosomal factors
Paracrine factors

paracrine factors

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Mutations in a homeotic selector gene cause which type of phenotype?

Loss of multiple segments

Loss of every other segment

Loss of half of each segment

Altered segmental identities

altered segmental identities

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How is the Hunchback (gap gene) protein gradient formed?

Translational control
Transcriptional control
mRNA localization
mRNA degradation

translational control

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The expression of the even-skipped gene in stripes during embryogenesis is an example of which of the following?

Combinatorial control
Modularity
Activation
Repression
A &amp; B
All of the above
None of the above

all of the above

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The primary role of the Hox genes during normal Drosophila development is to -_________.

Form segments

Determine the identity of segments

Promote cell division

Maintain functional homeostasis

Establish the anteroposterior axis.

determine the identity of segments

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The homeodomain encoded by all Hox genes has what function?

Enzymatic
DNA-binding
Cell signaling
Splicing
Cell-cell adhesion

DNA binding

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: Maternal effect genes control _______ of gap genes.

Transcription
Translation
Paracrine signaling

translation

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: Gap genes control ___________of pair-rule genes

Transcription
Translation
Paracrine signaling

transcription

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Pair rule genes control segemnt polarity genes by setting up a _______
feedback loop

Transcription
Translation
Paracrine signaling

paracrine signaling

: Gap and Pair-rule genes together control _____________ of homeotic genes

Transcription
Translation
Paracrine signaling

transcription

During amphibian gastrulation, the mesoderm and endoderm is brought to the interior of the embryo by which of the following movements? Ingression Involution Invagination Delamination

involution

Put the following Xenopus gastrulation events in order: 1. Epiboly of epidermis. 2. Involution of head mesoderm and chordamesoderm 3. Apical constriction and invagination of dorsal bottle cells 4. Formation of ventral bottle cells and blastopore ring

3,2,4,1

Which of the following is not a mechanism of amphibian involution? Radial intercalation Convergence and extension Delamination Vegetal rotation

delamination

Which of the following is not a involved in amphibian epiboly? Cell division Intercalation Apical constriction Fibronectin

apical constriction

The vegetal cells of an amphibian embryo become ____(this) germ layer, and they induce formation of _____(this) germ layer.

The vegetal cells become endoderm and induce the overlying cells to become mesoderm.

How are VegT and Vg1 localized to the vegetal cytoplasm? Transplantation Maternal deposit Cortical rotation Kinesin transport

maternal deposit

Which of the following best describes the function of the ‘organizer’ of the amphibian embryo. >1 correct Specifies dorsal side Initiates gastrulation Specifies ventral side Initiates cleavage

specifies the dorsal side | indirectly species the ventral side

Which of the following describes how endodermally expressed VegT induces the overlying mesoderm? As a ___ Transcription factor Signaling molecule Paracrine factor Splicing factor

transcription factor

Which of the following is NOT a property of the organizer? Establishes main body axes Induces endoderm Conditionally specified Autonomously specified

induces endoderm and autonomously specified

Which of the following proteins is localized in the ‘Nieukoop center’ and plays a role in inducing the organizer? b-catenin Notch intracellular domain Gli/Ci STAT

b-catenin

The following genes are expressed in the Nieuwkoop center. Which of these play a role in induction of the organizer? (more than one correct answer, submit all that are correct) ``` Beta-catenin Xnr Nodal Sox17 Vg1 Fibronectin Protocadherin ```

B-catenin Xnr Nodal Vg1

The following genes are expressed in the Nieuwkoop center. Which of these are expressed in a gradient or non-uniform manner in endoderm? (more than one correct answer) ``` Beta-catenin Xnr Nodal Sox17 Vg1 Fibronectin Protocadherin ```

B-catenin and Xnr

How is epidermal tissue induced in amphibian embryos? Wnt signaling Chordin induction BMP signaling BMP antagonists

BMP signaling (the antagonists block this induction)

Wnt and BMP gradients are modulated by which factors? (multiple correct) Diffusable antagonists Intracellular antagonists Translational control Transcriptional control

A,B,D

Zebrafish (and chick) embryos undergo which type of cleavage? >1 correct Meroblastic Holoblastic Syncytial Discoidal

meroblastic and discoidal

Which of the following best describes the embryonic shield of a Zebrafish embryo? ‘shields’ embryos from UV light Specifies the dorsal side of the embryo. Site of sperm entry Signals via Notch-Delta

specifies the dorsal side of the embryo

Which of the following structures is the Zebrafish equivalent of the amphibian Neiuwkoop center? Yolk syncytial layer Koller’s sickle The shield Hypoblast

yolk syncytial layer

Which of the following cellular structures are involved in left-right patterning of Zebrafish embryos. Endosomes Nodal Cilia centrosomes Extracellular matrix

nodal cilia

Which of the following is the most likely reason that there is no blastula-stage fate map of a Zebrafish embryo? Until sperm entry during gastrulation, there are no defined embryonic axes. The large yolk disposition keeps any cellular markers from being visible There is much cell mixing during cleavage. And the blastomeres can give rise to an unpredictable variety of tissues. Zebrafish embryos cannot survive injection with outside substances until later stages

There is much cell mixing during cleavage. And the blastomeres can give rise to an unpredictable variety of tissues.

There is much cell mixing during cleavage. And the blastomeres can give rise to an unpredictable variety of tissues. What is the likely state of differentiation of these early blastomeres? Pre-specification Specification Determination Differentiation

pre-specification and specification

The Zebrafish shield and dorsal Yolk syncytial layer are homologous to which of these Xenopus structures? Vegetal & animal Poles Blastula and Gastrula Head mesoderm and dorsal ectoderm Organizer/dorsal blastopore lip and Neiuwkoop center

Organizer/dorsal blastopore lip and Neiuwkoop center

Which protein IS NOT expressed by the Nieuwkoop center of Zebrafish? Squint (nodal-related) Beta-catenin Chordin Pitx2

chordin and Pitx2

Which of the following is NOT a property of the organizer? Establishes main body axes Induces endoderm Conditionally specified Autonomously specified

induces endoderm

The Chick hypoblast give rise to which of the following tissues? Endoderm Mesoderm Ectosderm Yolk sac

yolk sac

During chick gastrulation, the endoderm and mesoderm enter the embryo by which of the following processes? Invagination Ingression Delamination Involution

B. Ingression, (EMT then migration)

The Henson’s node in the chick embryo is the chick equivalent of which of the following structures? Spemann’s organizer Neiukoop center Anterior Visceral Endoderm (AVE)

A. Spemann’s organizer (the Neiukoop center of chick is near the secondary hypoblast where Koller’s sickle forms)

The ______ is the mammalian organizer, and it secretes ________ inhibitors such as Chordin and Noggin. Spemann’s organizer, BMP Neiukoop center, FGF Node, BMP

Node, BMP

True/False: Unequal Nodal and Pitx2 expression in amphibians, mammals, birds, and fish results in specification of the left-right axis

true

What does the trophoblast of a mammalian blastocyst become? Embryo Chorion Amnion Ectoderm

chorion

Which of the following is NOT true of mammalian cleavage? Asynchronous Rotational Meroblastic Takes 12-24 hrs/division Zygotic transcription occurs relatively early

meroblastic

Chick and mouse embryos contain different amounts of cervical vertebrae. Which of the following is thought to cause this difference? Hox expression Retinoic Acid Wnt signaling BMP signaling

hox expression