Biology Test Biology Developmental Biology & Embryology 2

Question 1

What is embryonic induction?

Accepted Answer

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

Answer

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.

Question 2

Hox genes are critical to animal development primarily because they:

Accepted Answer

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

Answer

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.

Question 3

What is the role of apoptosis in normal embryonic development?

Accepted Answer

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

Answer

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.

Question 4

What are neural crest cells and why are they significant?

Accepted 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

Answer

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.'

Question 5

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

Accepted Answer

Differentiation

Answer

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.

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Biology Test Biology Developmental Biology & Embryology 2