Biology

Embryonic Development

572 Questions

Embryonic development questions cover the biological processes of gamete fusion, germ layer formation, and fetal maturation. The focus lies in identifying extraembryonic structures, trophoblast functions, and sequential developmental stages. This specialized topic appears regularly in biology screening tests and medical entrance examinations.

Germ layer formationBlastocyst implantationExtraembryonic structuresFetal development stagesReproductive physiology

Embryonic Development Questions

Multiple choice

Embryo developed from the somatic cells are called

  1. cybrids

  2. embryoid

  3. callus

  4. hybrids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the somatic cells are cultured and the culture is made stationary, each cell starts differentiating into an independent embryo showing all the stages of embryo development. These embryos are called embryoids, which can give rise to a complete plant.

Multiple choice

Egg of Frog is

  1. Moderately telolecithal and mesolecithal

  2. Heavily telolecithal and polylecithal

  3. Microlecithal and homolecithal

  4. Polylecithal and centrolecithal
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Telolecithal also known as macrolecithal, refers to the uneven distribution of yolk in the cytoplasm of ovums found in birds, reptiles, fish, and monotremes. Mesolecithal eggs have comparatively more yolk than the microlecithal eggs. The yolk is concentrated in one part of the egg (the vegetal pole), with the cell nucleus and most of the cytoplasm in the other (the animal pole).

Multiple choice

Gonads are derived from

  1. Mesoderm

  2. Endoderm

  3. Ectoderm

  4. All the three layers
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In all bilaterian animals, the mesoderm is one of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and endoderm (inside layer), with the mesoderm as the middle layer between them.The mesoderm forms mesenchyme (connective tissue), mesothelium, non-epithelial blood cells and coelomocytes. Mesothelium lines coeloms; forms the muscles in a process known as myogenesis, septa (cross-wise partitions) and mesenteries (length-wise partitions); and forms part of the gonads (the rest being the gametes)

Multiple choice

The structure developing embryologically from the ceacum is

  1. Vermiform Appendix

  2. Ileum

  3. Duodenal bulb

  4. Duodenum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The appendix is a blind-ended tube connected to the cecum (or caecum), from which it develops embryologically. The cecum is a pouchlike structure of the colon. The appendix is located near the junction of the small intestine and the large intestine.

Multiple choice

Epithelial tissue originates from the

  1. mesoderm,endoderm and ectoderm

  2. ectoderm

  3. endoderm

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Epithelial tissues are derived from all of the embryological germ layers from ectoderm (e.g., the epidermis); from endoderm (e.g., the lining of the gastrointestinal tract); from mesoderm (e.g., the inner linings of body cavities).

Multiple choice

The correct sequence of events of embryogenesis in humans is

  1. fertilisation – zygote – cleavage – morula – blastula – gastrula

  2. fertilisation – cleavage – morula – zygote – blastula – gastrula

  3. fertilisation – zygote – blastula – morula – cleavage – gastrula

  4. cleavage – zygote – fertilisation – morula – blastula – gastrula
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct sequence of events after fertilisation.

Multiple choice

The mesenchyme arising beneath the germinal epithelium is the origin of which analogous cell types?

  1. Leydig and thecal cells

  2. Spermatogonia and oogonia

  3. Sertoli and granulosa cells

  4. Sex cords

  5. Umbilical cord
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mesenchyme arising beneath the germinal epithelium in the testes is the precursor to testicular interstitial cells or Leydig cells while in the ovaries, it is the precursor to ovarian stroma or thecal cells.