Biology Developmental Biology & Embryology Flashcards

What is embryonic induction?

Answer: The ability of one group of cells to signal adjacent cells to adopt a specific developmental fate

Embryonic induction occurs when an inducing tissue releases signals that cause a responding tissue to change its developmental trajectory, as in the notochord inducing neural tube formation.

Hox genes are critical to animal development primarily because they:

Answer: Determine positional identity along the anterior-posterior body axis by encoding transcription factors

Hox genes encode homeodomain transcription factors that specify segment identity along the anterior-posterior axis; mutations cause homeotic transformations where one body segment adopts the identity of another.

What is the role of apoptosis in normal embryonic development?

Answer: It sculpts structures by removing specific cells, such as the interdigital webbing between developing fingers

Apoptosis (programmed cell death) is essential for normal morphogenesis; it removes cells between developing digits, shapes the nervous system by eliminating excess neurons, and remodels many organ systems.

What are neural crest cells and why are they significant?

Answer: A highly migratory population derived from the dorsal neural tube that gives rise to diverse cell types including peripheral neurons, melanocytes, and craniofacial cartilage

Neural crest cells are a multipotent, migratory population that delaminate from the dorsal neural tube and travel throughout the embryo, contributing to an extraordinary variety of tissues sometimes called the 'fourth germ layer.'

Which term describes the process by which embryonic cells become increasingly structurally and functionally specialized during development?

Answer: Differentiation

Differentiation is the process by which cells acquire distinct molecular, structural, and functional characteristics as they develop from a pluripotent state toward a specialized cell type.

What is a morphogen gradient?

Answer: A concentration gradient of a signaling molecule that provides cells with positional information to guide their developmental fate

Morphogens are signaling molecules that form concentration gradients across a tissue; cells interpret their position in the gradient to adopt different fates, explaining how a field of cells generates diverse cell types.

What is organogenesis?

Answer: The process by which the three primary germ layers differentiate into the specific organs and organ systems of the body

Organogenesis is the embryonic stage following gastrulation during which the three germ layers interact and differentiate to form all recognizable organs and organ systems.