Developmental Biology Test IV Review

A comprehensive set of flashcards covering key concepts from Developmental Biology, focusing on neural induction, germ layer formation, and major developmental processes.

What does high BMP induce in ectoderm?

Epidermis

Which molecules inhibit BMP?

Noggin, Chordin, Follistatin

What is the role of the organizer in embryo development?

Dorsalizes embryo and induces neural tube formation.

What inhibits Wnt and BMP to help form the head?

Cerberus

What does the Nieuwkoop Center induce?

Organizer formation.

What do Nodal/Xnr specify?

Mesoderm and endoderm.

What is the function of Pitx2?

Defines left–right asymmetry.

What is the phenotype if noggin is overexpressed in a ventralized embryo?

It will induce neural tissue.

What does BMP inactivation do to Sox2 expression?

It enhances Sox2 expression.

What signals come from the vegetal pole during early development?

Cell signaling for mesoderm and endoderm.

What is the gray crescent?

The future dorsal side of the embryo.

What stabilizes β-catenin in dorsal regions?

Disheveled and Wnt11.

What characterizes the Mid-Blastula Transition?

Zygotic transcription starts and the cell cycle slows.

In which cell cycle do microtubules reorganize to form the gray crescent?

During the cleavage stage.

What is the role of fibronectin during gastrulation?

Guides migration.

Which protein is expressed in a labeled ectoderm region?

E-cadherin.

What is Frzb?

A secreted Wnt inhibitor.

What is the overall influence of Wnt signaling?

It posteriorizes structures.

What happens with ectopic Pitx2 expression in Xenopus?

It alters organ looping.

What role do morphogen gradients play in different species?

They control the A–P axis.

How do homeotic/Hox genes function in development?

They repress more anterior genes.

What does colinearity of Hox genes refer to?

Chromosomal arrangement reflects expression domains.

What effects do mutations in Hox genes have?

They can cause homeotic transformations.

What is the function of the Dorsal protein?

Specifies ventral cell fates.

What initiates the dorsal-ventral (DV) axis in Drosophila?

Expression of Pipe in follicle cells.

What type of cleavage is associated with low yolk?

Holoblastic cleavage.

What describes syncytial divisions?

Early cleavage patterns in Drosophila.

What do yolk content and cleavage patterns correspond to?

Yolk content determines cleavage pattern.

What controls shell chirality in snails?

Maternal factors.

How is dextral/sinistral inheritance determined?

By maternal-effect genes.

What are the characteristics of Hox genes?

They determine body patterning.

What is the effect of Pitx2 misexpression?

It alters organ positioning.

What does Wnt inhibition lead to?

Formation of anterior head structures.

Which molecules are involved in the organizer?

Nodal, Chordin, Noggin, Follistatin.

What defines the head during A–P axis formation?

Wnt and BMP inhibition.

What is the role of the Nieuwkoop Center?

Establishing the dorsal axis and inducing the organizer.

What defines the left side of the Xenopus embryo?

Nodal signaling.

How does gastrulation affect mesoderm induction?

Fibronectin guides cell migration.

What is the result of β-catenin stabilization during early development?

Induction of dorsal structures.

What are the primary roles of homeotic selector genes?

Determine segment identity.

What happens during the Mid-Blastula Transition?

Zygotic transcription begins.

What does the gray crescent indicate?

Future dorsal side of the embryo.

How is DV axis polarity established in Drosophila?

Gurken–Torpedo signaling.

What gene product defines ventral cell fates?

Dorsal protein.

How does fibronectin relate to embryonic development?

It guides migration during gastrulation.

What do Hox gene mutations lead to?

Homeotic transformations.

What is the effect of Noggin on ectoderm?

Promotes neural tissue formation.

Which family of proteins includes Nodal?

TGF-β family.

Which molecule is a secreted Wnt inhibitor?

Frzb.

What is the role of the Dorsal protein in the nucleus?

Specifies ventral identity.

What does β-catenin stabilization signify?

Dorsal specification.

What type of cleavage occurs in species with high yolk content?

Meroblastic cleavage.

How is the A–P axis established in different species?

Morphogen gradients influence axis specifications.

What are typical effects of irregular Hox gene expression?

Aberrant body segment identity.

How are Hox genes arranged in the chromosome?

In a linear order corresponding to their expression domains.

What indicates the presence of specific noggin molecules?

Neural induction.

Which signaling pathway is crucial for head development?

Wnt/BMP inhibition.

What is the significance of maternal-effect genes?

Establish early developmental patterns.

How does the Wnt pathway influence embryonic development?

Controls posterior identity.

What characterizes the role of cadherins in development?

They mediate cell adhesion.

What happens to embryos lacking Wnt signaling?

They may develop with head structures.

What signifies posterior development?

Wnt signaling presence.

What does disheveled influence in relation to β-catenin?

Stabilizes β-catenin in dorsal regions.