Biology Test Biology Developmental Biology & Embryology 3

Question 1

What is the primary function of the amnion in amniotic vertebrates?

Accepted Answer

It encloses the embryo in a fluid-filled cavity that cushions it from mechanical shock and prevents desiccation

Answer

It provides nutritive yolk reserves to the embryo

Answer

It exchanges respiratory gases between embryo and mother

Answer

It secretes digestive enzymes that process maternal nutrients for the embryo

Question 2

The trophoblast cells of the blastocyst are primarily responsible for:

Accepted Answer

Implanting into the uterine wall and forming the fetal contribution to the placenta

Answer

Forming the embryonic nervous system through neurulation

Answer

Producing yolk reserves that nourish the embryo during early development

Answer

Giving rise to all three primary germ layers during gastrulation

Question 3

What is cellular determination in developmental biology?

Accepted Answer

The irreversible commitment of a cell to a particular developmental fate, maintained even if the cell is transplanted to a new location

Answer

The final mitotic division that produces a terminally differentiated cell

Answer

The quantitative measurement of cell size during embryogenesis

Answer

The reversible specification of a cell's developmental pathway that can change with environmental signals

Question 4

Which description best defines stem cells in a developmental biology context?

Accepted Answer

Undifferentiated cells with the capacity for self-renewal and the ability to differentiate into one or more specialized cell types

Answer

Cells restricted solely to bone marrow that produce only blood cell lineages

Answer

Post-mitotic cells that have permanently exited the cell cycle

Answer

Fully specialized cells that perform a single dedicated physiological function

Question 5

What is hemimetabolism (incomplete metamorphosis) in insects?

Accepted Answer

A life cycle consisting of egg, nymph, and adult stages in which the nymph gradually resembles a wingless adult

Answer

A life cycle with four stages: egg, larva, pupa, and adult, with a dramatic transformation during the pupal stage

Answer

A developmental pattern unique to holometabolous vertebrates such as frogs

Answer

The incomplete sclerotization of the adult cuticle during eclosion

Question 6

What is the primary developmental significance of the notochord in vertebrate embryos?

Accepted Answer

It provides axial structural support and secretes signals that induce the overlying ectoderm to form the neural plate and tube

Answer

It directly ossifies to become the permanent vertebral column in adults

Answer

It generates the first erythrocytes needed for embryonic circulation

Answer

It differentiates into the epithelial lining of the gut and digestive glands

Question 7

What is totipotency in the context of cell development?

Accepted Answer

The capacity of a single cell to give rise to every cell type in the organism, including both embryonic tissues and extraembryonic structures such as the placenta

Answer

The capacity of a cell to undergo unlimited rounds of mitosis without senescence

Answer

The innate resistance of early blastomeres to programmed cell death

Answer

The electrical potential difference maintained across the membrane of a fertilized egg