Devolopmental Biology (all quizes)

When does cellularization of the Drosophila blastoderm occur, and what cytoskeletal filaments play a role in this process?

After nuclear division 13; actin filaments and microtubules

In the canonical (B-catenin dependent) Wnt pathway, when Wnt binds to the Frizzled receptor, why does this cause B-catenin to be saved from degradation? (Thereby allowing it enter into the nucleus and bind to the TCF transcription factor)

Because Wnt bound to Frizzled allows Frizzled to activate Disheveled, which becomes an inhibitor of the GSK3 protein. GSK3 cannot phosphorylate B-catenin, so it cannot target B-catenin for degradation inside the proteosome.

The concentration of the morphogen __ is highest at the anterior end of the Drosophila melanogaster syncytium's cytoplasm, whereas the concentration of the morphogen __ is highest at the posterior end.

Bicoid; Caudal

Match the 3 domains that a transcription factor usually has with how it works

Binds to specific sequences in the promoter and enhancer regions A. DNA-binding domain Enables the transcription factor to recruit histone-modifying enzymes B. trans-acting domain Enables the transcription factor to bind to other proteins that are bound to the enhancer or promoter sequences C. protein-protein interaction domain

Put the steps of RNA-seq in chronological order from first to last

1. mRNA extraction and polyA addition 2. Fragmentation of RNA 3. Conversion of mRNA to cDNA by reverse transcription and random priming 4. Ligation of adaptors to the ends of cDNA fragments 5. PCR amplification 6. Immobilization of PCR products on a plate or chip 7. Sequencing 8. Mapping of sequence reads to the genome 9. Data Analysis: Which transcript sequence reads are obtained tells us which genes are expressed in tissue A versus tissue B (or different developmental times); the number of sequence reads obtained per transcript in tissue A versus B tells us differential gene expression

What is the most common way that differentiated cells can be converted to induced pluripotent stem cells?

Activation of a different set of pioneer transcription factors

The phenomenon in which cells intercalate to narrow a tissue and at the same time lengthen it, is called:

Convergent extension

What signaling establishes the TIMING of somite formation from presomitic mesoderm?

Cyclic activation of Notch-Delta signaling

What is the difference between cytonemes and primary cilium in the way that they can receive paracrine factors?

Cytonemes are long projections that extend from the signal producing or receiving cell, connecting the two like a conduit Primary cilia are focal extensions of the cell membrane made by microtubules, and allow for asymmetric congregation of transmembrane receptors

In sea urchins, when does the fertilization cone form, and what is it made of?

Forms when the sperm cell membrane and egg cell membrane fuse; actin polymers

In Amphibians, a subset of the Wnt inhibitors produced in the pharyngeal endoderm have a second function other than inhibiting Wnt signaling. What is this second function?

Inhibit BMP signaling

What protein transcription factor is the main player in separating the single vertebrate eye field into 2 bilateral fields? What is the mechanism by which this occurs?

Inhibits Pax6 expression Shh

What cell adhesion molecule was experimentally found by knockout approach to be critical to maintenance of apicobasal polarity and the specification of the inner cell mass and trophectoderm cell lineages?

E-cadherin

What happens to the notochord in the adult?

It gets segmented into smaller units, which are retained and later develop into part of the intervertebral discs

In sea urchins, what allows sperm chromatin decondensation prior to the fusion of genetic material from the sperm and egg?

Kinases from the sperm acrosome phosphorylate sperm-specific histone proteins

Adult stem cells, residing in the adult stem cell niche, have the ability to divide and the daughter cells differentiate. However, adult stem cells upon division cannot produce more stem cells to repopulate the stem cell pool (unlike embryonic stem cells).

False

Cleavage in fish is holoblastic radial cleavage.

False

In all vertebrates, neural ectoderm is inhibited from forming where BMP-mediated induction of epidermal cells activated

False

Which of the below listed ligands binds to a receptor tyrosine kinase, which then phosphorylates itself and its homodimer receptor partner, prior to beginning a signaling cascade of phosphorylation of several cytoplasmic proteins?

Fgf8

In the mouse jaw, the mesenchyme is given tooth-forming ability by ___, and prevented from tooth formation by ___.

Fgf8; Bmp4

What 3 transcription factors need to be expressed to promote pluripotency of the inner cell mass?

Oct4 Sox2 Nanog

Which of the following eye tissues makes first contact with the ectoderm (during neural tube closure) to initiate the cascade of events the concludes with creation of the lens fibers ad lens epithelium?

Optic vesicle

Wnt signaling during otic and epibranchial induction promotes ___ identity while repressing ___ development. Later, ___ signaling supports the speciication of epibranchial neurons.

Otic identity; epibranchial; Bmp

__ signaling occurs between cells that are located a distance from one another, so that the signals produced by the inducing cell must pass through the extracellular matrix to reach the responding cell. In contrast, __ signaling occurs between cells with direct contact with one another.

Paracrine; juxtacrine

Which mesoderm flanks the notochord on both sides?

Paraxial mesoderm

In cave dwelling Mexican tetras, what 2 genes are expressed in broader domains when induced by Shh? Which gene's expression increased when Pax6 expression was repressed?

Pax2 In the cave dwelling fish, Ptc2 and Pax2 were expressed in broader domains when induced by Shh

Which of the following genes' expression is repressed by Sonic hedgehog (Shh) protein during eye development?

Pax6

When cardiomyocyte progenitor cells were infused into a decellularized heart (in which only the extracellular matrix was left behind), the cells differentiated and organized into a functionally contracting re-cellularized heart. In this example, the cells had already been specified and needed only an environment that would allow the expression of these traits. What type of inductive interaction is this between the extracellular matrix and the cardiomyocyte progenitor cells?

Permissive

Based on the revised flower development model, cells that express A, B, E activies will form __.

Petals

Prior to mammalian fertilization, high levels of progesterone present in the ampulla of the uterine tube may trigger release of __ from the sperm cell membrane. This is needed for activation of the __ cation channels. This allows an influx of __ into the sperm, causing exocytosis of the sperm's __.

Proteinase K; CatSper; calcium ions; acrosome

The part of the embryo in angiosperms that gives rise to the root is the __.

Radicle

Complete the following sentence. In epigeal germination, __

The hypocotyl is able to lift the cotyledons above the ground

Where does the Drosophila sperm enter the egg?

The micropyle, the future dorsal anterior region of the embryo

What are the two primary functions of the radial glial cells?

To serve as a scaffold for the migration of other progenitor cells and newly made neuron cells To serve as the major neural stem cell throughout embryonic and fetal development

In the case of angiosperms, the endosperm in the seed is __.

Triploid

Release of __ during egg maturation __ map kinase, to allow __ of the cell cycle.

calcium ions; deactivates; re-initiation

Electrical signals are received by a neuron's __.

dendrites

In fish, the first step of gastrulation is the __ of blastoderm cells over the yolk, caused by __ of the deeper blastula cells of the epiblast into the more superficiallly positioned layers of the epiblast layer. This causes the formation of the __ (the presumptive ectoderm) and the __ (the presumptive mesendoderm).

epiboly; radial intercalation; epiblast; hypoblast

The dermomyotome compartment of a mature somite will give rise to the muscle-forming __, and the dermis-forming __.

myotome; dermatome

In both amphibians and fish, ectodermal cells form __ tissue as long as BMP signaling is __. This mechanism occurs due to the presence of __, secreted by __ cells in fish.

neural; blocked; BMP inhibitors; the embryonic shield

Gene expression in Drosophila early embryo is delineated by __ boundaries; in contrast, adult structures are organized along the __ pattern.

parasegmental; segmental

In mammals, the cells of the inner cell mass are __ and can be cultured as embryonic stem cells. The inner cell mass cells give rise to the __ and to the __.

pluripotent; epiblast; hypoblast

The otic placode is made of ___ cells. The otic placode invaginates to eventually form the ___ adjacent to the neural tube.

pre-placodal ectoderm; otocyst

Which of the below factors guide sperm to the location where fertilization occurs?

progesterone released by cumulus cells calcium ions Increased temperature at site of fertilization

Drosophila are __ because their mouth forms __ their anus.

protostomes; before

The first step of cell fate maturation is __, in which the cell will continue to differentiate along its same fate if put into isolation. The second step of cell fate maturation is __, in which the cell will not change in culture even if a different cell type if placed next to it.

specification; determination

What affects which 5' and 3' intron splice sites are recognized in one cell type versus another? What are the different forms of the protein created by translating mRNAs that differ due to alternative pre-mRNA splicing called?

splice site recognition factors; protein isoforms

Fgf8 paracrine factor transcribed in the ___ extends its expression pattern posteriorly/caudally as this tissue grows. The concentration of this paracrine factor is regulated via ___. This will cause a higher concentration of Fgf8 ___ than ___.

tailbud; mRNA decay; caudally; rostrally

The most internal cells of the sclerotome are called the arthrotome, and become these tissues:

vertebral joints proximal portion of the ribs outer portion of the intervertebral discs

What is the mammalian version of the vitelline envelope extracellular matrix?

zona pellucida

Which of the following are true regarding pioneer transcription factors? Mark all that apply.

•The first transcription factors to begin making a locus in a heterochromatic region available for transcription. •Penetrate heterochromatic DNA regions and bind to their enhancer sequences. •Some function by recruiting histone modifying enzymes.

Where is Sonic hedgehog (Shh) expressed in the 12-day old mouse embryonic brain?

Prechordal plate

Both avian and mammalian gastrulation takes place through the __, the equivalent of an elongated blastopore lip of amphibian embryos.

Primitive Streak

Where does the eukaryotic RNA polymerase II bind in genes to turn on transcription?

Promoter

During human female oogenesis, meiosis is paused during __ until puberty.

Prophase I

In what phylum are snails? Are snails protostomes or deuterostomes? Which forms first in snails- their mouth or their anus?

Protostomes Mollusks mouth forms before anus

__ induction occurs when two interacting tissues both produce signals, and each tissue type is able to respond to the other's signals.

Reciprocal

Which of the following is NOT a role of transcription factors?

Regulate alternative splicing of mRNAs

What genes' proteins regulate the expression of segment polarity genes in the Drosophila embryo?

Regulated by pair-rule genes' proteins Banding pattern is alternating stripes in every other parasegment One function is to reinforce the parasegmental periodicity established by the earlier transcription factors One function is to establish cell fates within each parasegment by cell to cell signaling

Acetylation of histone proteins of nucelosomes causes __ of chromatin and thus __ of expression of genes in this region of the genome.

Relaxation; activation

What are the blocks to polyspermy in mammals?

Release of zinc ions that bind to the zona pellucida, that inhibit acrosin and MMP2, as well as enzymes that establish sperm capacitation Cleavage of ZP2 Release of Juno protein from oocyte membrane

Match each paracrine factor or transcription factor with its role in dynamic formation of the eye field in the anterior neural plate. Some answers may be used more than once.

Role of Otx2 C. Specifies the forebrain and midbrain Noggin's effects on BMPs and WNTs D. Inhibition Noggin's effect on ET expression D. Inhibition Otx2's effect on Noggin expression D. Inhibition Effect of ET protein on Rx1 gene expression F. Activation Effect on Rx1 protein on Otx2 expression D. Inhibition Effect of Rx1 protein on Pax6 expression F. Activation Effect of Pax6 protein on cascade of gene expression constituting the eye field B. Pax6 initiates gene expression cascade constituting the eye field

By day 17.5 of the mouse inner ear development, where are the areas where hair cells develop?

SM (Saccular macula) Cochlear duct UM (Utricular macula) Organ of Corti

What gene's expression affects whether the presence of Wt1 and Sf1 in the genital ridge of the bipotential gonad triggers testis or ovary development? If this gene (and it's expression) IS present, what pathway does it block? When Sox9 is activated, it activates synthesis of the paracrine factor __, which stimulates testis development, and blocks __ paracrine factor.

SRY; B-catenin; Fgf9; Wnt4

The __ gene on the Y chromosome encodes a transcription factor that activates the __ gene. This gene product serves as a __ which activates a gene encoding __, a hormone that represses female oviduct formation, as well as other genes whose products promote testis development.

SRY; Sox9; transcription factor; anti-Mullerian hormone (AMH)

During anther development, the tapetum arises from __

Secondary parietal cell

If a fetus is XY, the mesodermal cells proliferate through week 8, when a subset of these cells begin differentiation into __ cells. These will surround the incoming germ cells and organize themselves into __. At puberty in humans, these will mature to form __. The germ cells will migrate to the periphery of these tubules, where they will establish the __ stem cell population. The other major group of mesodermal cells will differentiate into __ cells, which secrete testosterone.

Sertoli; testis cords; seminiferous tubules; spermatagonial; Leydig

The sclerotome of the somite regions are specified predominantly by the paracrine factor __, which is secreted by the notochord and floor plate cells. The notochord and somites also secrete Gremlin and __, two BMP antagonists. The abscence of BMP is critical in allowing ___ to induce cartiledge formation.

Shh; Noggin; Shh

Decrease or loss of ___ signaling in the notochord leads to notochord sheath defects. This leads to defective ___, leading to abnormal ___.

Shh; nuclei pulposi; intervertebral discs

Match the following terms with their definition

Single cell asymmetry D. A stem cell divides into 1 stem cell and 1 committed cell Population asymmetry (symmetrical differentiation) C. One stem cell divides into 2 stem cells. A different stem cell in the niche divides into 2 committed cells. Adult stem cell lineage A. A multipotent stem cell transitions to a committed stem cell capable of making one or very few types of cells, to a progenitor cell that can multiply but is transient in its life and committed to a particular cell type, to a differentiated cell Symmetric cell division B. All cells divide to form 2 cells of identical cell type

Along the anterior-posterior axis of the paraxial mesoderm, neural cell fate specification is fostered by the upregulation of __, which is inhibited by ___ posteriorly

Sox2; Tbx6

When mammalian sperm reach the cumulus complex surrounding the egg, what allows them to proceed through the cumulus complex?

Sperm hyperactivation Release of hyaluronidase enzyme

As vertebrae formation occurs, the most dorsal region of the sclerotome will become the __. The most ventral region of the sclerotome before it expands will become the __, surrounding the notochord.

Spinous process; Vertebral body

During anther dehiscence, the part of the anther that ruptures to release the pollen is the __.

Stomium

In female developing ovaries, the primary germ cells initiate meiosis due to upregulation of the __ transcription factor, due to _____ that were produced by the nearby kidney. In males' developing testes, __ is downregulated by __, and __ is degraded by a testes' produced enzyme __.

Stra8; Wnt4 and retinoic acid; Stra8; Fgf9; retinoic acid; Cyp26b1

Ectoderm cells that are exposed to low levels of BMP, so Sox transcription factors are expressed will become __.

Surface ectoderm

Ectoderm that is exposed to high levels of BMP will become __.

Surface ectoderm

During embryogenesis in angiosperms, the part of the embryo in the 8-cell stage that anchors the embryo to the endosperm to obtain nourishment is called:

Suspensor

In the Drosophila ovarian stem cell niche, cap cells secrete __ family proteins (which are paracrine factors), which activate the BMP signal transduction pathway. This prevents germ stem cell differentiation by repressing differentiation related gene expression, like __ expression. The extracellular matrix restricts diffusion; therefore, further distant germ stem cells do not detect the ligand secreted by the cap cells. and will therefore allow expression of differentation related genes, and differentiate into __.

TGF-B; bam; oocytes

What are the 3 pioneer transcriptional regulators that control early speciication of the presomitic mesoderm (PSM)?

Tbx6 Brachyury Mesogenin

When Nieuwkoop took embryonic newt cells from the roof of the blastocoel (often called the animal cap) in the animal hemisphere, and placed them next to the yolky vegetal cells from the base of the blastocoel, what happened? How is this interpreted?

The animal cap cells differentiated into mesodermal tissue; the blastocoel keeps the animal cap cells separated from the vegetal cells; keeping the animal cap cells undifferentiated

In sea urchins, match the following causes to their consequences during egg cell activation.

Membrane potential change F. Fast block to polyspermy Degradation of cyclin and inactivation of Map Kinase J. Restoration of mitotic cell cycle Ca2+ release, leading to activation of NAD+ kinase, leading to conversion of NAD+ to NADP+ G. membrane biosynthesis Cortical granule exocytosis effect on polyspermy H. Slow block to polyspermy Cortical granule exocytosis 2nd effect (not effect on polyspermy) C. Formation of hyaline layer Ca2+ release and an increase in intracellular pH A. Stimulation of protein synthesis, DNA replication, and cytoplasmic movements of morphogenetic material Udx1 activity's effect on vitelline envelope B. Hardening via cross-linking

What cleavage pattern do Drosophila egg cells undergo initially after fertiliation?

Meroblastic superficial cleavage

In ventricular radial glial cells, how does the PAR-3 protein affect asymmetric cell division, where one mitotic daughter cell remains a stem cell while the other becomes primed for neuronal differentiation?

The apically distributed PAR-3 protein recruits a protein complex that segregates Notch signaling proteins. Higher Notch concentration in the apical region of the cell leads the mitotic daughter cell receiving the apical cytoplasm to stay a stem cell. Mitotic daughter cells that receive basal cytoplasm with less Notch instead express the Notch receptor Delta. When they detect Notch on the neighboring cell, they become primed for neuronal differentiation.

What does it mean if a blastula is termed a stereoblastula, as exists in snails?

The blastula has a very small or absent blastocoel

In the snail embryo development, which of the following are true?

The cells resulting from the first 2 cleavages are approximately the same size Division alternates dextral and sinistral every subsequent cleavage; the embryos are termed dextral or sinistral based on the location of the micromere relative to its macromere sister cell at the 3rd cleavage

How is the fast block to polyspermy achieved in sea urchins?

The egg's membrane potential increases after the first sperm entry, due to chemicals in the fusing sperm's cytoplasm altering the sodium ion channels on the egg cell membrane

What are the anterior cranial placodes?

The lens placode The adenohypophyseal placode The olfactory placode

What genes' proteins regulate the expression of the homeotic selector genes? What is the function of the homeotic selector genes? What is the role of the Antennapedia complex? What is the role of the Bithorax complex?

The role of the Bithorax complex is to specify the 3rd thoracic segment and the abdominal segments The function of the homeotic selector genes is to specify the characteristic structures of each segment pair-rule and gap gene proteins regulate the expression of homeotic selector genes The Antennapedia complex specifies the head and first 2 thoracic segments

Match the following terms with their definition or function in mammalian gastrulation.

The signaling center in the mammalian gastrula that is critical for formation of the notochord and in patterning axial structures caudally from the midbrain B. The node The signaling center in the mammalian gastrula that is critical for establishing the body axis by controlling the patterning of adjacent embryonic tissues and thereby defining the future anterior side of the embryo. E. The anterior visceral endoderm (AVE) The posterior gradient of FGF along with an opposing anterior gradient of retinoic acid in the primitive streak region causes differential activation of these genes __, that are homologous to Drosophila homeotic selector genes. This differential activation patterns cell fates along the anterior-posterior axis D. Hox genes Which 2 protein types are activated on the left side of the mammalian embryo to allow establishment of the left-right body axis? C. Nodal and Pitx transcription factor The initial expression of Nodal in the left side of the lateral plate mesoderm is due to: I. Detection of right to left fluid movement in the node, detected by crown cells neighboring the node.

Describe epiboly in amphibian gastrulation, and what powers it? (Total of 2 answer selections)

The thinning and spreading of animal cap cells over the vegetal hemisphere cell proliferation and radial intercalation

Which of the following apply to mammalian embryonic cleavage?

The trophoblast cells produce the chorion portion of the placenta Cell divisions occur asynchronously The cells of the inner cell mass of the 16 cell morula become positioned on one side of the ring of trophoblast cells (decendents of the external cells of the morula) After the first 3 cleavages, cells become very compact due to E-cadherin linking them together holoblastic rotational cleavage

In amphibians, What are the 4 Wnt inhibitors expressed in the pharyngeal endoderm that block Wnt signaling from the ventral and lateral mesoderm?

Tiki Dickkopf Frzb Cerberus

Use matching to name the cells and their cell fates in this fate map of the sea urchin embryo.

Top rectangle, which is blue, pointing to cells of the embryo that are in the animal hemisphere C. Cell fate: Ectoderm Light pink box, referring to the central portion of the embryo A. Cell fate: Non-skeletogenic mesenchyme Veg2 cells of the embryo, specified to become pink box cells and darkest yellow box cells D. Cell fate: Non-skeletogenic mesenchyme and foregut Veg1 cells of embryo only, specified to become light yellow box cells and the cells surrounding them (light blue box cells) E. Cell fate: Hindgut and ectoderm surrounding it Veg1 and Veg2 cells together B. Cell fate: Midgut

T or F: Enhancer elements work in both a combinatorial and modular fashion

Ture

What type of cleavage do amphibians have? Why is this the case?

Unequal (displaced) radial holoblastic cleavage because the greater abundance of yolk in the vegetal hemisphere makes these cells divide slower and thus be larger than cells in the animal hemisphere

When performing single cell RNA sequencing, how is it determined once one obtains the sequencing reads, which RNA sequence came from each cell?

Unique sequence "barcodes" are added onto the 5' and 3' end of each cDNA produced from reverse transcription of each mRNA. The same barcode sequence is added onto each cDNA derived from each mRNA isolated from a single cell.

High expression of Shh by the notochord causes it to be secreted to the __ region of the neural tube. The high concentration of Shh in this region of the neural tube induces __ expression in the ventral region of the somites. This causes the ventral region of the somite to develop into ___.

Ventral; Pax1; sclerotome

Place the below steps of a signal transduction cascade in chronological order from first to last.

1. A paracrine or juxtacrine factor binds to a cell membrane receptor and causes a conformational change. 2. The cytoplasmic domain of the receptor obtains enzymatic activity. 3. The receptor phosphorylates other cytoplasmic proteins. 4. A transcription factor or set of factors activates or represses specific gene activity.

Put the different layers of the human epidermis in order from most internal to most external.

1. Dermis 2. Basement Membrane 3. Basal Layer 4. Spinous layer 5. Granular layer 6. Stratum corneum

Place the below steps of the epithelial to mesenchymal transition in chronological order from first to last.

1. Epithelial cells are attached to one another through adherens junctions containing cadherin, catenins, and actin rings. They are attached to the basal lamina through integrins. 2. paracrine factors from neighboring cells alter gene expression in target cells that change or downregulate their expression of cadherins. 3. Cell adhesions are broken, and the basal lamina dissolves due to the secretion of enzymes that break it down 4. The target cell escapes from the epithelium, escaping to the mesoderm

Put the following steps of the animal life cycle in chronological order, beginning with the creation of a new organism.

1. Fertilization 2. Cleavage 3. Gastrulation 4. Organogenesis 5. Maturation 6. Gametogenesis

Place the steps of the Smad pathway in chronological order from first to last.

1. TGF-B-like ligands bind to the type I and type II receptors. 2. The type II receptor phosphorylates the type I receptor 3. The activated type I receptor phosphorylates the Smad proteins. 4. The Smad proteins dimerize with Smad4 5. The Smad heterodimer enters the nucleus and activates or represses transcription by binding to enhancer elements of target genes

Place the steps of Notch/Delta juxtacrine signaling in chronological order from first to last.

1. The Delta ligand on one cell binds to the extracellular domain of the Notch protein on an adjacent cell. 2. A conformational change on the intracellular domain of Notch occurs 3. Notch activates a protease 4. The intracellular domain of Notch enters the nucleus 5. The intracellular domain of Notch binds to the CSL transcription factor, displacing the repressor protein bound to CSL. The intracellular domain of Notch also binds transcriptional activators.

Put the below steps of Drosophila embryo gastrulation in chronological order from first to last.

1. About 1000 cells making up the ventral midline of the embryo invaginate to produce the ventral furrow, and the invaginated cells will eventually become the ventral tube. 2. The prospective endoderm cells and pole cells invaginates to form 2 pockets- one at the anterior end of the ventral furrow, and one at the posterior end of the ventral furrow. 3. The ectoderm bends to form the cephalic furrow 4. The surface ectodermal cells and the mesoderm undergo convergence and extension, migrating toward the ventral midline to form the germ band- cells that will later form the trunk of the embryo. 5. The germ band extends posteriorly and wraps around the dorsal surface of the embryo 6. The body segments begin to appear 7. The germ band retracts to put the presumptive posterior segments at the posterior tip of embryo 8. At the dorsal surface, the two sides of the epidermis are brought together during dorsal closure

Put the 5 steps of the interaction between egg and sperm in chronological order from first to last.

1. Chemoattraction of sperm to egg based on soluble molecules secreted by egg 2. Binding of sperm to the extracellular matrix of the egg 3. Exocytosis of sperm acrosomal vesicle and release of its enzymes 4. Passage of sperm through ECM to the egg cell membrane 5. Fusion of egg and sperm cell membranes

Put the steps of amphibian gastrulation in chronological order from first to last

1. Epiboly of ectoderm 2. Invagination of bottle cells to form dorsal blastopore lip 3. Coordinated involuation of mesoderm 4. The archenteron forms and displaces the blastocoel 5. Cells from the lateral and ventral lips of the blastopore migrate into the embryo 6. Cells of animal hemisphere migrate down towards vegetal region, moving the blastopore to the region near the vegetal pole 7. The blastocoel is obliterated, and the embryo becomes completely surrounded by ectoderm, all endodermal cells are now internal, with mesodermal cells between these two layers

Put the below steps of sea urchin gastrulation in chronological order from first to last.

1. Micromeres detach from vegetal plate and migrate into the blastocoel 2. The micromeres develop into the skeletogenic mesenchyme, which forms skeletal rods of the sea urchin larva 3. The vegetal plate invaginates to form the endodermal archenteron, with a tip of non-skeletogenic mesenchyme cells 4. The archenteron elongates by convergent extension and is guided to the future mouth region by the non-skeletogenic mesenchyme

Put the following steps of mammalian sperm capacitation in chronological order from first to last.

1. Removal of cholesterol from sperm cell membrane 2. Influx of bicarbonate ions and calcium ions 3. Activation of adenylate kinase SACY 4. Elevation of cAMP concentrations 5. Activation of Protein Kinase A (PKA) 6. Phosphorylation of tyrosine kinases 7. Phosphorylation of sperm proteins and hyperactivation of sperm (the latter also due to increased calcium ion concentrations) 8. Sperm capacitation

Which cells degenerate when breast feeding has stopped?

Alveoli cells

How are hinge points formed during neural tube closure?

Apical constriction of dorsolateral hinge point cells and medial hinge point cells to make them wedge shaped Cell packing in the neural folds Basal thickening due to the basal location of nuclei in the cells

Plants produce stem cells in specialized organs to allow shoot and root tip growth. These specialized organs are called __.

Apical meristems

What phylum does Drosophila melanogaster belong to?

Arthropods

Match each with what type of tissue each will develop into.

Arthrotome D. Vertebral joints, proximal rib, outer disc Dorsomedial sclerotome H. Spine, arch entrolateral sclerotome E. distal rib Ventromedial sclerotome G. Vertebral body Notochord A. Inner disc/nucleus pulposus Ventral posterior sclerotome B. Endothelial precursor, followed by outer dorsal aorta Syndetome F. tendons Dermatome C. Dermis

The addition of cholesterol to the C-terminal end of the Hedgehog protein has two important functions. What are they?

Assists in modulating extracellular transport. Necessary for Hedgehog to anchor to its Patched receptor on the membrane of the receiving cell.

When does egg activation in Drosophila occur?

At egg ovulation, a few minutes before fertilization occurs

What is the hormone that confers apical dominance in plants?

Auxin

in amphibians, Wnt signaling causes a gradient of __ along the anterior-posterior axis of the neural plate, which appears to specify the regionalization of the neural tube.

B-catenin

What determinants in the 3D macromere of snails are transferrred to the 4d blastomere that regulate the development of the 4d blastomere's decendent cells to form heart, muscles and hindgut, and also often prevented gastrulation when absent?

B-catenin Notch juxtacrine signaling receptor Nanos protein

In fish, the embryonic shield is induced by __ and underlying __ cells expressing __ paracrine factors

B-catenin; endodermal; Nodal-related

What gene is found only in humans and controls cerebral cortex folding? In what cell type is this gene specifically expressed?

ARHGAP11B radial glial cells

What is the genotype of individuals with congenital adrenal hyperplasia, and what is the cause?

XX; they produce too much testosterone in their ovaries or adrenal gland

A friend has a calico cat that has been sexed at a veternarian's office and determined to be male. What sex chromosomes would expect him to have?

XXY

Women with androgen insensitivity syndrome have a __ genotype. The presence of the __ gene activates expression of the Sox9 gene, which activates __ synthesis, stimulating testis development. The testes produce testosterone and __, which forces degeneration of the __, making these women sterile. Although these women produce testosterone, they have a mutation that __. Because the women do still produce estrogen from their __, they have female secondary sex characteristics.

XY; SRY; Fgf9; AMH; Mullerian ducts; prevents testosterone from being detected due to the mutation being in its receptor protein; adrenal glands

In amphibians, left-right axis specification depends on the __ protein being preferentially accumulated on the __ side of the embryo. This localization is driven by the __ rotation of __ that creates a leftward current across the midline of the embryo. One of the key genes activated by this protein encodes the transcription factor __, that controls the respective position of the __, and gut __.

Xenopus Nodal-like 1; left; clockwise; cilia; Pitx2; heart; coiling

During primary neurulation, __ is expressed by the surface ectoderm distally flanking the neural crest cells. __ is expressed in the dorsal neural folds. __ is expressed in the notochord and the floor plate of the neural groove, and is required for floor plate specification. BMP inhibits dorsal and lateral __ formation, except where it is inhibited by __.

BMP; Noggin; Shh; hinge; Noggin

During establishment of the different mesodermal subtypes, the specification of chordamesoderm, paraxial mesoderm, intermediate mesoderm, and lateral plate mesoderm occurs due to a ___ gradient, where the highest concentration is more ___, and the lowest concentration is more ___.

BMP; lateral; medial

Which layer of the human epidermis is mitotically active?

Basal layer

Which method is used to detect DNA sequences that particular proteins of interest, such as transcription factors, bind to through the use of an antibody specific for the protein of interest being used to purify DNA fragments bound to that protein. This is followed by separation of the DNA from the protein of interest, and sequencing of the DNA.

CHIP-seq

The method of introducing a guide RNA and Cas9 endonuclease into cells to create a targeted DNA mutation through either nonhomologous end joining or homology directed repair is called:

CRISPR-Cas9 genome editing

This signal produced by CAR cells and mesenchymal stem cells in the adult hematopoietic stem cell niche can transition HSCs into proliferative behavior, but downregulation of this signal in the perivascular niche enchourages migration of short-term active HSCs into oxygen rich blood vessels.

CXCL12

In sea urchins, What molecule needs to be degraded or downregulated to allow de-adhesion of skeletogenic mesenchyme cells from their neighbors to begin the epithelial to mesenchymal transition? What transcription factor controls downregulation of this cell connecting molecule? What transcription factor, (that is controlled by the double negative gate of the GRN), is responsible for activating expression of the transcription factor that controls downregulation of the cell connecting molecule?

Cadherins; Snail; Alx1

What is the name for the transmembrane receptors that bind fibronectin molecules in the extracellular matrix and cytoskeletal proteins on the inside of the cell, in order to connect cells to the extracellualr matrix?

Cadherins; catenins

___ cells lie under the pial surface of the central nervous system and secrete the extracellular protein __- the same protein that also regulates layering in the cerebellum. Here, this protein influences the outward migration of precursor cells along the radial glial cell's basal process. Reception of this protein by the migrating precursor cells makes them increase expression of __, allowing them to attach to other cells expressing the same cell adhesion related molecule.

Cajal-Retzius; Reelin; N-cadherin

In mammals, sperm that have undergone the acrosome reaction can recognize the zona pellucida of the egg by binding to egg- __. The sperm then move through the zona pellucida and reach the oocyte. There, the protein __ on the sperm cell membrane meets a complex of __ and other proteins on the egg cell membrane. This initiates sperm cell membrane and egg cell membrane fusion, and entry of __ into the egg. If the sperm's acrosomal reaction hasn't occurred yet by the time it reaches the zona pellucida of the egg, the sperm must first bind to egg-__, then undergo the acrosomal reaction, and then exchange binding with egg-___. The rest of the pathway is the same.

ZP2; Izumo; Juno; the sperm; ZP3; ZP2

The inability to convert testosterone to its __ derivative nevertheless allows male embryos to develop functional testes, for their Wolffian ducts to develop, and for their Mullerian ducts to degenerate. However, as children, they are identified initially as female because __.

DHT; their testes fail to descend

What transcriptional regulator of pre-somitic mesoderm specification strongly influences expression of Tbx6?

Mesogenin 1

The epidermis, nervous system, and pigment cells are derived from the __. The lining of the digestive tube and the respiratory system are derived from the __. The kidneys, gonads, muscles, bones, heart and blood cells are derived from the __.

Ectoderm, endoderm, mesoderm

Which of the below events begin during the mid-blastula transition?

Enhancement of zygotic gene transcription cellularization slowdown of nuclear division degradation of maternally provided mRNAs

What signaling system regulates epithelialization during somite boundary formation?

Eph-ephrin signaling

Which of the following processes describes how cells organize into functional structures through cell growth, cell migration, and cell death?

Morphogenesis

In sea urchins, the sperm and egg pronuclei move towards each other by __. Pronuclei contact activates enzymes that produce specific fusion promoting __, to allow production of the diploid zygote nucleus.

Movement along microtubules; lipids

Which of the following are differences between human brains from the brains of most non-primates (excluding elephants)?

Expresses ARHGAP11B highly folded (gyrencephalic) The human brain continues growing until puberty Myelination of white matter increases rapidly in certain areas of the brain at puberty The existence of some human specific alleles of developmental regulatory genes, such as non-coding RNAs Different enhancer element sequences allow higher gene expression of brain function related genes in humans

Mammalian sperm do not complete capacitation until they reach the egg.

False

Neural plate formation occurs after gastrulation.

False

Shh has diminished secretion in cave dwelling tetras (fish) compared to surface water dwelling fish of the same species

False

T or F: The differential adhesion hypothesis states that cell types having greater cell cohesion segregate outside of cells with less cohesion.

False

The cerebral cortex is only organized in the vertical direction, creating 6 layers with different functional properties and the types of neurons found there.

False

There are multiple ways to track where embryonic cells migrate during development, and what type of differentiated cell they become. One can use vital dyes, genetic labeling through the use of antibody hybridization, or fusing of a gene expressed only in some cells to a fluorescent reporter gene such as GFP to produce a fluorescent fusion protein. These methods allow the creation of a __ that shows on the embryo which cells become which type of larval or adult structures.

Fate map

Ectoderm that is exposed to moderate levels of BMP will become the __.

Neural crest

Why does expression of Sxl in female Drosophila occur earlier than in males ? How is RNA splicing of the Sxl pre-RNA different in male versus female Drosophila?

Females produce more of the 4 transcription factors necessary to turn on Sxl because they have genes for them on both X chromosomes. RNA-splicing of the Sxl transcript in males includes exon 3 with premature stop codon, but RNA splicing of Sxl transcript in females removes exon 3.

The lens placode is induced to differentiate to the ___ by ___ signals. These signals are secreted by adjacent ___ cells (which are undergoing their own differentiation to the neural retina)

Fgf Fgf8, Bmp4, Delta Signals secreted by adjacent optic vesicle cells

Which of the following are secreted by dermal fibroblasts to promote proliferation of basal epidermal cells?

Fgf10 Tgf alpha Igf EgfR ligands Fgf7

During the telogen (stem cell quiescence) to anagen (stem cell activation) transition of hair follicle development, What factors are produced by the Dermal papilla mesenchymal cells that are secreted to the nearby hair follicle stem cells to allow their differentiation?

Fgf7 Bmp inhibitors Wnts Fgf10

Secretion of ___ by the myotome induces syndetome formation, which will develop into tendons. Developing cartiledge cells are induced by ___ secreted from the notochord and neural tube floor plate to synthesize the ___ transcription factors. These transcription factors present in the developing cartiledge cells blocks expression of the ___ gene, making sure that developing cartiledge cells are not re-programmed to become tendon cells.

Fgf8; Shh; Sox5, Sox6; Scleraxis

In amphibians, what intracellular signaling proteins produced in the anterior region of the embryo in future head region cells are required for blocking BMP and Wnt signals from reaching the nucleus, and for inducing the brain and sensory placodes?

Fibroblast Growth Facctors Insulin-like Growth Factors

In amphibians, what extracellular matrix component creates a lattice that mesoendodermal cells crawl along within the blastocoel to migrate towards the animal pole? What cells secrete this extracellular matrix component?

Fibronectin glycoprotein; presumptive ectoderm cells of blastocoel roof

Match the following cell types with whether they are totipotent, pluripotent, multipotent, or unipotent. An answer may be used more than once.

First 4 to 8 cells of the zygote D. Totipotent Cells of the inner cell mass of the blastocyst A. Pluripotent Resident stem cells within each germ layer of the embryo, or the adult brain C. Multipotent Spermatogonia B. Unipotent Adult stem cells such as hematopoietic stem cells C. Multipotent Adult Intestinal Stem Cells C. Multipotent

How does folic acid deficiency cause neural tube defects?

Folic acid deficiency causes changes in chromatin structure by histone modification Folic acid deficiency changes DNA methylation patterns Epigenetic modifications alter expression of genes necessary to be expressed for neural tube closure

Which of the following are non-vascular plants? Mark all that apply.

Hornworts Mosses Liverworts

Once Hox gene expression reaches the trunk of the organism (more posterior than anterior along the anterior-posterior axis), how does this affect axis elongation and somitogenesis?

Hox gene expression causes inhibition of Wnt signaling, causes the tailbud to stop growing, terminating axis elongation. Wnt3a inhibition by Hox genes causes no additional formation of presomitic mesoderm, so no additional somites can develop.

In ear development, which develops first- the otic vesicle or the otic cup? In eye development, which develops first, the optic vesicle or the otic cup?

In ear development, the otic cup develops before the otic vesicle In eye development, the optic vesicle develops before the optic cup

Match the following precursor organs present in the embryo to what they differentiate into during secondary sex determination.

In females, the Part of urogenital sinus that doesn't become the bladder and urethra, instead becomes H. Skene's glands Mullerian ducts, in females G. Uterus, vervix, oviducts, upper vagina genital tubercle, in females C. clitoris labioscrotal folds, in females B. labia majora Wolffian ducts (male) A. epididymis and vas deferens genital tubercle in males F. penis labioscrotal folds, in males D. scrotum Part of urogenital sinus that doesn't form bladder and urethra, in males, develops into E. prostrate gland

What is the order of tissues from most internal to most external in the bud stage of ectodermal appendage development, prior to morphogenesis? What happens during the bud stage?

In the bud stage, superficial cells of the placode contract and intercalate toward the center, causing them to pucker inwardly. This drives the epithelium into the underlying mesenchyme Mesenchyme, Condensed mesenchyme, epithelium

In Drosophila, what allows the doublesex pre-RNA sequence to be spliced in a female specific manner rather than a male specific manner?

In the presence of the Sxl protein (only functional in females), the tra pre-RNA is spliced in a female specific manner to Tra and Tra2. Both are necessary to splice the doublesex RNA transcript in a female specific manner.

What connects the epidermal basal layer to the basement membrane?

Integrin-Laminin 5 connections

What are the two driving forces for ectodermal epiboly and convergent extension of the mesoderm?

Intercalation of deeper ectodermal cells with surface ectodermal cells by following C3a guidance Radial intercalation of several layers of involuting marginal zone (IMZ) cells to form one thin broad layer, prior to involuting into the embryo

How does Fgf8 indirectly regulate the retinoic acid gradient in paraxial mesoderm development?

It activates Cyp26b. Cyp26b inhibits retinoic acid biosynthesis

I am a non-vascular plant with a thallus. The sporophyte of my life cycle cannot photosynthesize, only the gametophyte. What am I?

Liverwort

During formation and then separation of the neural tube from the presumptive epidermis, what allows the neural plate cells that will become the neural tube to separate from the adjacent presumptive epidermis cells flanking either side of the neural plate?

Loss of E-cadherin

At what stage of maturation is the sea urchin egg at the time the sperm enters it? At what stage of maturation is the human egg at the time the sperm enters it?

Meiosis complete; metaphase II of meiosis

What are the purposes of the 2 centrioles inside the sperm?

One centriole, together with microtubles, makes up the axoneme motor protein of the flagellum One centriole enters the egg and divides into two to create the mitotic spindle of first cleavage

Which of the following is NOT a part of the cytoskeletal machinery that positions each nucleus in a syncytial blastoderm to receive unique concentrations of determination factors?

cellulose microfibers

Which of the following are NOT provided within the egg's cytoplasm?

centrioles

Unlike in spermatogenesis, during meiosis I of oogenesis, the meiotic spindle lacks __. Because of this, the microtubules of the meiotic spindle are organized by numerous __ consisting of mRNAs and enzymes that form around the nuclear envelope at first meiotic prophase.

centrioles; microtubule organizing centers (MTOCs)

After mammalian fertilization, enzymes released from the __ cleave ZP2 and ZP3, preventing further sperm binding to them. The enzyme that cleaves ZP2 is named __.

cortical granule fusion with the egg cell membrane; ovastacin

The slow block to polyspermy in sea urchins is achieved by the fusion of the membranes of __ with the egg cell membrane, releasing the enzyme __, which cleaves protein posts that connect the __ and egg cell membrane. This enzyme also cleaves off __ receptors on the __, and any sperm attached to them.

cortical granules; serine protease; vitelline envelope; bindin; egg cell membrane

The protein MeCP2 can bind to methylated cytosines of DNA. MeCP2 can recruit histone __, which remove acetyl groups from histone proteins, leading to __. The same MeCP2 protein bound to methylated cytosines can instead recruit histone __, which add methyl groups to histone proteins, leading to __.

deacetylases; repression of gene expression; methyltransferases; repression of gene expression

Sea urchins and tunicates are classified as __ because their anus forms from the __, and the mouth is formed later elsewhere.

deuterostomes; blastopore

In amphibians, the __ and its descendent cells are called the organizer because they contain __, which induces expression of genes that initiate the movement of the involuting mesoderm. The first __ cells to migrate over this tissue will induce the ectoderm above them to become anterior structures such as the forebrain. The next cells to migrate over this tissue will become more posterior structures, such as the hindbrain and __. This process is called __.

dorsal lip of blastopore; B-catenin; mesodermal; spinal cord; primary embryonic induction

In fish, on the future __ side of the embryo, the ______ intercalate to form the __, which is a homologous structure to the organizer in amphibians. If you take this tissue and transplant it to the ventral side of a different embryo, what will happen? ___

dorsal; hypoblast and epiblast; embryonic shield; a second dorsal-ventral axis will form

Ganglia are generated from both the otic and epibranchial placodes by cell delamination and cell migration. In the case of epibranchial placodes, neural progenitor cells delaminate as neuroblasts from the epibranchial placodes. These cells migrate ___, guided by the ___ tunnels created by these cells migrating ___.

dorsally; neural crest tunnels; ventrally

In amphibians, the organizer is induced to form by the Nieuwkoop center. The Nieuwkoop center is located in the __ cells, which is where there is a high accumulation of __. This molecule combines with __, which is by itself a repressor, but is converted to an activator through this interaction. This protein complex can activate transcription of the __ genes on the __ side of the embryo.

dorsalmost vegetal hemisphere; B-catenin; Tcf3; Siamois and Twin; dorsal

The syndetome arises from the most __ region of the __, the ventromedial cells of the somite (the cells of the somite closest to the neural tube and notochord)

dorsomedial; sclerotome

Mesenchymal stem cell differentiation is influenced by the __ of the matrix they are grown upon. The loss of MSCs or their ability to __ has been correlated but not proven to be a component of the normal aging syndrome.

elasticity; differentiate

In tunicates, B-catenin accumulation in the A4.1 and B4.1 blastomeres specifies these cells to become __ cells. FGFs (fibroblast growth factors, which are paracrine factors) are secreted by __ cells, and indirectly induce expression of the __ gene. The produced protein binds to cis-regulatory elements of __ and mesenchyme development genes, performing conditional specification.

endodermal; endodermal; Brachyury; notochord

In fish, the deep cells of the blastoderm form between these two layers:

enveloping layer yolk syncytial layer

Crepidula fornicata is a medium sized sea snail. The first larva to settle on an unoccupied substrate develops into a female, which produces chemicals that attract other larvae. These larvae settle on top of her and develop into males, which become mates for the original female. This initial phase of sex determination (occuring before some of those males switch sex to females) is a type of __.

environmental sex determination

Unlike embryonic stem cells, induced pluripotent stem cells may retain chemical alterations to histone proteins or methylation of DNA that are similar to the adult somatic cell that the iPSCs were derived from. These are called __.

epigenetic modifications

During female puberty, what molecule causes the terminal end buds to expand to form ducts?

estrogen

At the outer boundary of the __ of the cerebellum, neural progenitor cells multiply and come into contact with cells that secrete BMPs. These BMPs specify the mitotic daughter cells of the neural progenitor cells to become a type of neuron, called __ cells/neurons. These cells migrate back towards the ventricular zone, but stop at the __, where they form a new region called the __.

external granule layer; granule; intermediate zone, internal granule layer

What are the 3 principal mechanisms that allow cell shape changes leading the lens vesicle to form into the optic lens?

filopodial protrusions to the retina basal constriction apical constriction

Which method allows the detection of mRNAs produced and visuallized within cells via hybridization with a labelled antisense mRNA probe?

in situ hybridization

Paracrine factors are produced by __ cells, and can trigger a specific response in nearby __ cells if those cells are __ to receive it.

inducer; responder; competent

In the sea urchin blastomere, which cells are autonomously specified? What maternally inherited mRNA is expressed into a transcriptional regulator protein that is allowed to accumulate in the vegetal cells, allowing their specification cell fates? What maternally inherited mRNA, once expressed in the vegetal cortex of the egg, prevents degradation of the transcriptional regulator that is the answer to the second question in the micromere and veg2 macromere cells?

large micromeres; B-catenin; Disheveled

In order to have the same X-linked gene dosage in female mammals compared to males, one X chromosome out of the two in females is inactivated (you learned this already in genetics). What is the mechanism by which 1 X is inactivated?

long non-coding RNAs trigger the DNA of one chromosome to become transcriptionally inactive heterochromatin

In mammals, what are the two germ layers produced due to migration of epiblast cells through the primitive streak?

mesoderm endoderm

During the __ transition of amphibians, chromatin first becomes relaxed due to absorption of some component in the egg. Vegetal cells, under direction of the __ protein become __ and begin secreting factos that induce the cells above them to become __.

mid-blastula; VegT; endoderm; mesoderm

The paraxial mesoderm is formed from ___

migrating mesodermal cells

Cadherins can cause cells to sort by both quantitative (different amounts of cadherin) and qualitative (different types of cadherin) differences. Even in a heterotypic aggregate of cells, cells expressing __ cadherin will have a __ surface tension and migrate __ to those expressing __ cadherin.

more; higher; internally; less

If cells exposed to a high concentration of a paracrine signal turn on the expression of a different set of genes determining cell fate specification in comparison to cells exposed to a lower concentration of the signal, the paracrine factor is said to be a __.

morphogen

In mammals, what events allow movement of the oocyte released from the ovary to the site where it will be fertilized?

muscle contractions of the fimbriae Cilia beating within the infundibulum and the ampulla of the oviduct/uterine tube Fimbriae at upper end of oviduct pick up oocyte-cumulus complex

The primaxial and abaxial myotome regions are specified by different paracrine factors, but in both cases, ___ are induced in the cells that will become muscles.

myogenic regulatory factors

Cells that are at the apex of the neural folds will delaminate from their neighbors to form the __. Upon fusion and separation of the neural tube from the epidermis, the cells referred to in the first answer will do this : ____.

neural crest; migrate away from the region to become a number of cell types

In amphibians, the default specification for ectodermal cells is __ tissue. This specification is permitted through the action of __. The action of __ on ectodermal cells specifies them to become __ tissue.

neural; BMP inhibitors; BMP; epidermal

During the 3rd and final stage of sea urchin archenteron elongation (after the epithelial to mesencymal transition), which cells within the archenteron extend filopodia through the blastocoel fluid to contact the inner surface roof of the blastocoel, attaching and pulling up the archenteron?

non-skeletogenic mesenchyme

In amphibians, the organizer consists of these 4 tissue types:

notochord head mesoderm pharyngeal endoderm dorsal blastopore lip

In the central nervous system, what type of cells cover the axons in the marginal zone, and what do they cover these axons with to prevent electric current from being sent to an axon that is touching another axon?

oligodendrocytes; myelin sheaths

In females, the primary germ cells that reach an ovary divide rapidly from the 2nd to 7th month of embryonic gestation, forming __. Most of them die, but the survivors enter prophase I of meiosis, becoming __. Because meiosis I was stalled during Prophase I, these cells are __, and stay that way until meiosis resumes, normally at __. At this time, meiosis I resumes, producing haploid __ and __ (which disintegrates). Meiosis II then begins through the __ stage. After the secondary oocyte exits the ovary, it will only complete meiosis II if __ occurs.

oogonium; primary oocytes; diploid; puberty; secondary oocytes; polar bodies; metaphase II; fertilization

Long-term quiescent hemapoietic stem cells (HSCs) in the endosteal niche associate with __ cells. Short-term active HSCs associate with __. Mobile HSCs and __ cells associate with stromal __ cells and __ stem cells.

osteoblast; blood vessels; progenitor cells; CAR; mesenchymal stem cells

Cell division in the trophectoderm that occurs __ to the apicobasal axis is __ in nature, and results in 1 additional cell in the trophectoderm and 1 inner cell mass cell created. In contrast, cell division in the trophectoderm that occurs __ to the apicobasal axis is __ in nature, and results in expansion of the trophectoderm only.

perpendicular; asymmetrical; parallel; symmetrical

The __ is a protrusion that forms and is then absorbed at the vegetal pole of the snail embryo. On the first cleavage, the cytoplasm that entered into this protrusion will be absorbed by the __ blastomere. Upon second cleavage, the cytoplasm flowing into the protrusion is absorbed into the __ blastomere.

polar lobe; CD; D

The removal of inhibitory sections of an protein to activate it, or addition of modifications to tag the protein to be transported to speciic intracellular destinations to function are two types of __.

post-translational gene expression regulation

During otic and epibranchial induction, cells in the ___ region of the non-neural ectoderm are induced to become otic-epibranchial progenitors by ___-derived ___ signaling

posterior pre-placodal region; head mesoderm; Fgf

The nanos mRNA is sequestered at the __ pole of the embryo. The Nanos protein __ the translation of the __ mRNA at the __ end of the embryo.

posterior; inhibits; hunchback; posterior

If a fetus is XX, germ cells that enter the gonad are organized into clusters, and surrounded by __ cells. These cells will later differentiate into __ cells. The germ cells will become __, and will be surrounded by follicles made up of __ and __ cells.

pre-granulosa; granulosa; oocytes; thecal; granulosa

The myoblasts in the myotome that are the closest to the neural tube form the ___ muscles, which include the musculature between the ribs and deep muscles of the back. The myosblasts in the myotome that are farthest from the neural tube form the ___ muscles of the body wall, limbs, and tongue. The dermatome will form several derivatives, including ___.

primaxial; abaxial; back dermis

During mammalian early brain development, the anterior portion of the neural tube forms 3 primary vesicles, the ___ (forebrain), ___ (midbrain), and ___ (hindbrain). In the ___, a segmental pattern forms that specifies the places where certain nerves originate- these segmental periodic swellings, called ___, allow cells within that terrority to mix, but not to mix with cells from an adjacent swelling. Neural crest cells derived from these swellings will form ___, clusters of neuronal cell bodies whose axons form a nerve.

proencephalon; mesencephalon; rhombencephalon; rhombencephalon; rhombomeres; ganglia

Sea urchins exhibit __ cleavage early in cleavage. Thier first two divisions are __ and perpendicular to each other. The third cleavage is __, and splits the animal and vegetal hemispheres from each other. The fourth cleavage is very different. The 4 cells in the animal hemisphere divide __ into 8 mesomeres of equal size. In contrast, the 4 cells of the vegetal hemisphere divide __ and unequally into 4 __ in the upper tier of vegetal cells and 4 __ at the vegetal pole.

radial holoblastic; meridional; equatorial; meridionally; equatorially; macromeres; micromeres

In mammals, sperm capacitation occurs in the __, and provides 3 new abilities to the sperm. These are:

recognition of cues to guide them to the egg Ability to undergo the acrosome reaction oviduct Ability to fuse with the egg cell membrane

As the dermomyotome and sclerotome expand, each __ splits into an anterior and posterior segment. As the spinal neurons grow outward to innervate the muscles of the myotome, the __ segment of each ___ combines with the __ segment of the next anterior sclerotome to form a vertebral rudiment.

sclerotome; anterior; sclerotome; posterior

Although it is true that methylation of histones is often used to __ gene expression, the __ and __ affect whether histone methylation activates or represses gene expression.

silence; position of the lysine amino acid; number of methyl groups added

There are two models for egg activation. In the first model, __ from the sperm trigger __ to activate __, which produces IP3 and DAG. IP3 causes release of __ from the __ organelle of the egg, whereas DAG along with the released ions, activates the ___ in the egg cell membrane. In the second model, binding of __ on the sperm cell membrane to receptors on the egg cell membrane activates __, which activates __, which produces IP3 and DAG. The remainder of the pathway is the same as for the 1st model of egg activation.

soluble factors; tyrosine kinase; phospholipase C (PLC); calcium ions; ER; sodium-hydrogen exchange pump; bindin; tyrosine kinase; phospholipase C (PLC)

The epithelial lining of the mammalian intesting projects villi which are alternated with crypts containing adult intestinal stem cells (ISCs) at their base. Surrounding the basal surface of the crypt are __ cells, which secrete opposing morphogenic gradients of __ (promoting stemness) and __ (promoting differentiation).

stromal pericryptal cells; Wnt2b; Bmp4

What is the name of the longitudinal groove that divides the dorsal and ventral halves of the neural tube? Which half of the neural tube is involved in effecting various motor functions? Which half of the neural tube is involved in receiving sensory neuron input?

sulcus limitans; ventral; dorsal

In the Drosophila egg, nuclear division occurs several times without cytokinesis, creating a single cell with many nuclei residing in one common cytoplasm. The term for this is a __.

syncytium

__ are exogenous environmental substances that disrupt normal development, but may or may not be mutagenic.

teratogens

Which of the below are maternal effect genes?

torsolike caudal hunchback pumilio bicoid nanos

Observing combined features of fin and leg in Tiktaalik rosease allows us to suggest it was the first aquatic species to walk on land. This combined feature of an earlier and later species is called a __.

transitional morphological state

Primary germ cells that arrive at the genital ridge of male embryos are called gonocytes, but de-differentiate into __. These are induced to differentiate into type B spermatogonia by ____. The type B spermatogonia go though a __ division to form primary spermatocytes (which are __). The primary spermatocytes then undergo __, producing secondary spermatocytes, which are __. The secondary spermatocytes then go through Meiosis II, and are now considered __.

type A spermatogonia; BMPs and Wnts; mitotic; diploid; Meiosis I; haploid; spermatids

In tunicates, the yellow cortical cytoplasm and inner clear cytoplasms contract into the __ hemisphere of the egg within 5 minutes of sperm entry. This migration of yellow lipids forms the __, which extends from the vegetal pole to the __. What determinant transcription factor is in the yellow cytoplasm that activates several mesodermal genes as well as genes for muscle actin and myosin?

vegetal; yellow crescent; equator; Macho-1

As the neural tube matures, neuroepithelial cells become __ cells in the ventricular zone. During initial neurogenesis, these cells can divide but be specified asymmetrically, causing the daughter cells to become more cells of the same type or become __ cells. As mid-neurogenesis continues, ventricular radial glial cells will divide to produce 1 cell of the same type, and one __ cell. These latter temporary cell types will later divide to create two __ cells. As time progresses, remaining ventricular radial glial cells divide to form one ___ and one intermediate cell. During late neurogenesis and gliogenesis, differentiation is __. Ventricular radial glial cells can divide to become 2 __ or 2 __.

ventricular radial glial cells; neuron; intermediate progenitor cell; neuron; outer radial glial cell; symmetrical; neurons; macroglia

Low CpG-content promoters are characterized by:

•Their default state is repressed by H3K27me3 and DNA methylation •Their active state requires activating (H3K4me3) histone modification and stimulation by transcription factors •Methylated cytosines can be bound by MeCP2, which binds to histone deactylases and histone methyltransferases, tightening the nucleosome-DNA complexes •Their poised state has nucleosomes enriched in H3K27me2 histone modifications

During mammalian fertilization, __ ion oscillations activate a kinase that leads to proteolysis of __, leading to __ of MAP kinase, allowing completion of meiosis. These ion oscillations also lead to the proteolysis of __, which activates separase to allow cleavage of cohesin rings attaching chromosomes at metaphase.

calcium; cyclin; inactivation; securin

The blastocoel of the morula is formed by a process called __, in which the __ cells secrete fluid into the morula using sodium pumps that move sodium __ the central cavity. This causes water to be drawn in osmotically, creating and enlarging the blastocoel.

cavitation; trophoblast; into

Failure to close neural tube sites __ in the rostral neural tube keeps the __ neuropore open, resulting in a lethal condition called ___.

2 or 3; anterior; anencephaly

In amphibians, What are the two functions of the three proteins secreted by the orgnaizer?

Block the BMP signal that would otherwise ventralize the mesoderm Activate epidermal genes in the ectoderm

In the telogen (stem cell quiescence) stage of hair follicle development, What paracrine factors are produced by the inner bulge layer that keep the hair follicle stem cells quiescent? What paracrine factor is produced by the dermal fibroblast cells that also inhibits hair follicle stem cell specification? What paracrine factor is produced by the subcutaneous fat cells (adipocytes)?

Bmp6, Fgf18 Bmp4 Bmp2

Which of the following apply to high CpG-content promoters (HCPs)?

By default in an active state The poised state has both activating and repressing histone modifications of the nucleosomes, and RNA polymerase II bound to the promoter but transcription does not occur. The repressed state has only repressing histone modifications present

How is anterior-posterior specification of the somites determined?

By the expression patterns of Hox genes in the paraxial mesoderm before somite development

In amphibians, the anterior-posterior axis is determined by a gradient of __ proteins, with the head having the __ concentrations of these proteins.

Wnt; lowest

What transcription factor is upregulated in the outer cells of the morula to promote trophectoderm differentiation and repress differentiation of the inner cell mass to the epiblast?

Cdx2

Which of the following processes do plants NOT perform?

Cell migration

__ are the comon ancestors of all animals, whereas __ are the common ancestors of all land plants.

Choanoflagellates; charophytic algae

What event below occurs at the same time that the somites form in the chick embryo

Closing of the neural tube

What triggers the acrosome reaction in sea urchins? How does the acrosomal protein bindin get onto the sperm cell surface membrane? What mediates the formation of the acrosomal process (a cellular protrusion extending from the head of the sea urchin sperm

Contact of sperm cell membrane receptors with polysaccharides present in the egg jelly; fusion of the acrosomal membrane with the sperm cell membrane; actin microfilaments

Match each type of cell specification with its definition. Some answers may be used more than once.

Cytoplasmic determinants (often transcription factor proteins) are specifically distributed in different regions of the egg, so that after fertilization, the cells of the early blastomere have received different transcription factors determining their fate. A. Autonomous specification Cells achieve their fates dependent on their position and thus interaction with adjacent cels. C. Conditional specification Multiple nuclei exist within a pre-blastoderm, and the migration of these nuclei toward the cortex is followed by membranes forming around each nucleus to form individual cells. Both spatial distribution of determination factors in the blastoderm AND the position of a given cell relative to neighboring nuclei determine a particular cell's fate. B. Syncytial specification Cell fate is determined by the physical properties of the cell's local environment (mechanical stress) C. Conditional specification

In sea urchins, which cells of the blastula lose their cell adhesion to the hyaline layer and to their neighbors, and increase their affinity for the basal lamina and ECM to initiate the epithelial-mesenchymal transition?

Descendents of the large micromeres

Differential gene expression can have multiple possible mechanisms. Which of the below is NOT a cause of differential gene expression (with very few exceptions)?

Different DNA genome in different cell types

Which of the following is NOT an example of translational gene expression regulation?

Differential pre-messenger RNA processing

When DNA replication occurs, each parental strand that is used as a template is methylated on some cytosines, and this was performed by the enzyme __. The newly synthesized strand is initially not methylated, but similar chemical groups are added on the newly synthesized strand in regions modified on the template strand. The enzyme that recognizes methyl groups on cytosines on the parental strand, and adds them in similar location on the newly synthesized strand is named __, and is called a perpetuating methyltransferase.

Dnmt3; Dnmt1

Where do primordial germ cells form? What paracrine factor induces their formation? When do the PGCs become able to express genes to produce differentiation related genes?

Form outside the gonads; BMP; upon their migration into the gonads

What are the two known ways that migrating neural crest cells can regulate which cells within the dorsomedial and ventrolateral lips of the dermomyotome maintain self-renewal capability or differentiate into different myocyte types?

GCP4 and Wnt1 production (and thus signaling) by migrating neural crest cells, detected by Wnt receptors on the surface of dorsomedial lips of the dermomyotome Delta production by migrating neural crest cells, detected by Notch receptors on the membranes of cells at the dorsomedial lips

What genes' proteins activate or repress the expression of gap genes? Where are gap genes expressed? How do mutations in gap genes affect the body plan of Drosophila?

Gap genes are expressed in one or two broad domains along the anterior-posterior axis Mutations in gap genes cause loss of large regions of the body (several contiguous segments) maternal effect genes

Vascular plants that make seeds found in cones belong to __.

Gymnosperms

A double negative gate is when a repressor locks specification genes, but the gate can be unlocked by a repressor of the repressor. In sea urchins, what protein inhibits micromere identity, and where is it expressed? What protein represses the protein that is the answer to the 1st question? What protein that specifies micromere identity upregulates expression of the protein that is the answer to the 2nd question?

HesC; Pmar1; B-catenin

What type of cleavage pattern do mollusks exhibit?

Holoblastic spiral cleavage

What types of target genes are differentially turned on to allow morphogenesis into a hair, tooth, or mammary gland?

Homeobox genes

Match the substages of meiosis with what occurs during that stage.

Homologous chromosomes align along their entire length thanks to the synaptonemal complex D. Pachytene stage of Prophase I Homologous chromosomes separate except at chiasmata connetion points between adjacent sister chromatids E. Diplotene stage of Meiosis I The stage of Meiosis I where crossing over does NOT take place A. Leptotene Protein that protects cohesin holding sister chromatids together, until Meiosis II B. Sgo2 (Shugoshin) Protein that, when activated, digests cohesin holding homologous chromosomes together C. Separase Protein that, when activated, digests no longer protected cohesin holding sister chromatids together during Meiosis II C. Separase

__ structures in different species are those that evaolved from a common ancestor. __ structures in different species are those that evolved independently due to a common function/need. Select the BEST answer.

Homologous; analogous

The optic vesicle ultimately transforms to the __, by being induced by the ___ tissue. This inducing tissue produces and secretes ___ as the signaling molecules to transform the neighboring optic vesicle to its cell fate.

Neural retina; Lens placode; Fgf

Match the following terms with definitions or facts about them. Some answers may be used more than once.

Neuroepithelial cells are a type of __ stem cell H. multipotent Venticular (ependymal) cells are derived from __. G. Neuroepithelial cells Radial glial cells are derived from __. G. Neuroepithelial cells Cerebrospinal fluid is secreted from ___. B. Ventricular (ependymal) cells Neurons of the brain that are organized into layers A. Laminae Neurons of the brain that are arranged into clusters E. Nuclei The original neural tube is formed from a layer of rapidly dividing neural stem cells that is once cell thick. This cell layer is called the __. D. Germinal neuroepithelium Where do dividing stem cells in the ventricular zone of the neural tube migrate to? C. Migrate to form a 2nd layer of cells within the neural tube The original, first present, cells of the neural tube in the ventricular zone will later shrink to become the __ that lines the brain cavity K. ependyma The cell body of the neuron is also called the __. J. Soma

How is timing of tissue maturation of the embryo correlated to neurulation?

Neurulation occurs in the anterior to posterior direction, causing further tissue maturation to also occur in the anterior to posterior direction along the axis of the embryo

In amphibians, the organizer is induced to form by the __, made of endodermal cells located in the dorsalmost vegetal region (equatorial region). This center is formed by translocation of the __ protein which grabs onto GBP (GSK3-binding protein) and functions to inactivate __ by separating it from the degradation complex and preventing it from binding to __. This only occurs at the point opposite the site of sperm entry, which is the future __ side of the embryo.

Nieuwkoop center; Disheveled; GSK3; B-catenin; dorsal

In experiments where the Lhx2 transcription factor was conditionally knocked out, what was the resulting brain defect phenotype?

No cerebral cortex forms

What was the effect of Rx1 knockout on mouse eye development?

No eyes form, but ear development and placement are normal

In amphibians, what 2 proteins act together to produce an additive activation of Smad2?

Nodal Vg1

What is the role of formin, and what is the role of Nodal in snail shell coiling?

Nodal activates expression of the Pitx1 transcription factor in D-quadrant blastomeres Nodal protein expressed in the C-quadrant micromeres activates genes on the right side of dextrally coiling embryos and on the left side of sinistrally coiling embryos Formin mRNA is inherited maternally in the oocyte from mothers possessing at least one copy of the dominant allele. Formin protein binds to actin and helps align the cytoskeleton of cells.

What inhibits BMP4 activity in abaxial myoblasts, necessary for proper development of these msucle precursor cells?

Noggin

In amphibians, the organizer functions by secreting these 3 proteins:

Noggin Chordin Follistatin

BMP4 (as well as Fgf5) are produced by the lateral plate mesoderm. ___ secreted from the notochord is a BMP antagonist, and prevents BMP4 in the ___ region of the lateral plate mesoderm from being able to specify the ___ region of the somite to become dermomyotome.

Noggin; dorsal; ventral

Match the following terms involved in the ventricular-subventricular zone (V-SVZ) stem cell niche with facts about regulation of quiescence, stem cell maintenance, or differentiation.

Notch signaling E. When constant levels are present in type B stem cell, promotes quiescence. EGF C. Produced by progenitor (transit amplifying) C cells. When detected by neighboring B stem cells, it has the effect of oscillating or even attenutating Notch activity, leading to differentiation of type B cells into type C progenitor cells VCAM1 D. A cell adhesion molecule localized to the apical end of B cells; its inhibition causes a loss of neural stem cell quiescence BMP signaling A. Produced by endothelial cells and at high concentrations at the basal side of the V-SVZ, it promotes gliogenesis. Noggin B. Produced by ependymal cells on the apical side of the V-SVZ stem cell niche, it inhibits neurogenesis. Jagged1 (Jag1) F. A transmembrane receptor made by endothelial cells, when bound by the Notch receptor on the endfoot of a B cell, it causes the cleavage of the intercellular domain of Notch. This intercellular domain is a transcription factor that promotes B1 cell quiescence.

When does garstrulation begin in mollusks?

When a few dozen cells have formed

Opposing gradients of morphogens play a role in inducing cell specification along the anterior-posterior axis of the paraxial mesoderm. Which morphogen(s) are highly expressed posteriorly and upregulate expression of Mesogenin and Tbx6? What does upregulation of Mesogenin and Tbx6 promote?

Wnt3a and Fgf8; Promotes presomitic progenitor specification and represses neural cell fate specification

The bipotential gonad is moved into the female pathway (ovary development) by the ___ and ___ genes, which promote accumulation of ___ via the ___ pathway. This inhibits the development of gonadal cells into testis cell types and activates genes that pomote the gonadal cells to develop into follicle cells of the ovary.

Wnt4; Rspo1; B-catenin; Wnt

Where within the female reproductive system does internal fertilization normally take place in mammals?

ampulla

In humans, Failure to close neural tube closure site 1 at the junction between the spinal cord and the hindbrain causes the defect __. Failure to close neural tube closure point 5 in the lumbar and sacral vertebrae region causes the defect __.

anencephaly; spina bifida

The bicoid mRNA is sequestered at the __ end of the embryo. Bicoid protein diffuses throughout the syncytium but is at its highest concentration at the __ end of the embryo. Bicoid is a transcription factor which activates the __ gene. Bicoid protein represses the translation of the __ mRNA in the __ end of the embryo.

anterior; anterior; hunchback; caudal; anterior

The earlier expressed Hox genes are expressed by cells positioned more ___ in the embryo. Earlier expressed Hox genes are located in more __ positions on chromosomes than later expressed Hox genes

anteriorly; 3'

In the case of ferns, the gametangia that produce male gametes are called __.

antheridia

As the early neural tube closes, the __ surface of the neuroepithlial cells borders the __ . The __ surface of the neuroepithelial cells swell to create __ on these cells.

apical; internal cavity of the neural tube; basal; endfeet

In mammals, egg activation occurs __ due to __ ions released from intracellular stores via the action of __ and __. Unlike in sea urchins, __ may come from the sperm and enters the egg during gamete fusion.

at fertilization; calcium; IP3; phospholipase C; phospholipase C

What type of cleavage does the tunicate (sea squirt) exhibit?

bilateral holoblastic cleavage

In sea urchins, after the acrosome reaction has occurred, the sperm protein __ binds to the __ of the egg in a species-specific manner.

bindin; egg cell membrane

In human fertilization, when the sperm and egg pronuclei meet, their membranes __. Then the condensed chromatin of each __. Only at ___ is a zygote nucleus formed.

break down; aligns along a common mitotic spindle; 2-4 cell divisions

How do osteoblasts keep HSCs quiescent?

by secreting angiopoietin-1 and thrombopoietin

What genes' proteins initiate transcription of the primary pair-rule genes? What genes' proteins regulate expression of the secondary pair-rule genes? What is the banding pattern of pair-rule genes? What is the function of pair-rule gene expression?

gap genes primary pair-rule genes expression in alternating stripes Function is to activate the segment polarity genes

If DNA methylation is present on only one gene allele but not the 2nd allele on the homologous chromosome, this can be one cause of __. This process of DNA methylation in a sex-specific manner occurs during __. This can cause an allele of a gene to be expressed or not expressed depending on whether that allele was inherited from the mother or father.

genomic imprinting; spermatogenesis and oogenesis

Neural stem cells of the mantle, or intermediate zone, differentiate into these 2 cell types:

glia neurons

What is the maternal mRNA that initiates dorsal-ventral patterning in the Drosophila oocyte? Where does this mRNA get localized? Where does its encoded protein have the highest concentration in the oocyte? What is the receptor for this protein and what cells produce it?

gurken is the maternal mRNA that establishes dorsal-ventral patterning in the oocyte The mRNA gets localized in a crescent between the oocyte nucleus and the oocyte cell membrane at the dorsal anterior of the oocyte The encoded protein has its highest concentration in the dorsal anterior region of the oocyte The receptor that recognizes this protein is the Torpedo receptor, located on the surface of follicle cells surrounding the oocyte

In mammals, cleavage is __, but modified to allow the formation of a __, which is an organ possessing tissues and blood vessels from both the embryo and the mother. This organ allows gas exchange, nutrient uptake, and waste elimination of the embryo.

holoblastic; placenta