Biology

Embryonic Development

621 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

Epiblast present in certain monocot embryo represents

  1. secondary cotyledon

  2. mesocotyl

  3. rudimentary stems

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The epiblast in monocot embryos (like grasses) is a small structure near the embryonic shoot. It's considered a vestigial or rudimentary second cotyledon, which explains why monocots appear to have only one cotyledon (scutellum) while ancestrally having two.

Multiple choice

In which of the following animals does the developing embryo have a third germinal layer in between the ectoderm and endoderm?

a. Platyhelminthes b. Chordates c. Coelenterates

  1. Only a and b

  2. Only a and c

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option. Platyhelminthes and chordates are the animals in which the developing embryo has a third germinal layer, called the mesoderm, in between the ectoderm and endoderm.

Multiple choice

The process by which unfertilized egg develops into a complete individual is known as _________.

  1. oogenesis

  2. embryogenesis

  3. parthenocarpy

  4. parthenocissus

  5. parthenogenesis
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Parthenogenesis is defined as the process in which the new individual is produced directly from the egg without undergoing fertilization. Honey bee, rotifers and some species of fishes and lizards in vertebrates exhibit the phenomenon of parthenogenesis.

Multiple choice

Embryonic stem cells are derived from

  1. fertilized embryo

  2. unfertilized embryo

  3. sperm

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

Embryonic stem cells (ESCs) are derived from the inner cell mass of a fertilized embryo at the blastocyst stage (approximately 5-7 days post-fertilization in humans). Option A is correct. Unfertilized embryo (B) is a contradiction in terms - an embryo by definition results from fertilization. ESCs cannot be derived from sperm (C) alone or adult tissues like kidney (D) - those would be adult stem cells if any. The key feature of ESCs is their pluripotency, derived from the earliest stages of embryonic development after fertilization has occurred.

Multiple choice

From the point of ontogeny, liver is

  1. mesodermal

  2. endodermal

  3. ectodermal

  4. both ectodermal and endodermal

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The liver develops from the endodermal germ layer during embryogenesis, arising as an outpouching of the foregut. This endodermal origin is consistent with the digestive tract and its accessory organs. Ectoderm forms skin and nervous tissue, while mesoderm forms muscle, bone, and connective tissue.

Multiple choice

The epidermis, which forms the outer layer of the skin, is derived from

  1. endoderm

  2. ectoderm

  3. mesoderm

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

The epidermis is the outermost layer of skin and develops from the ectoderm, one of the three primary germ layers in embryonic development. The ectoderm gives rise to superficial structures like skin epidermis, hair, nails, and the nervous system. Endoderm forms internal organs like the gut lining, while mesoderm forms muscles, bones, and connective tissue.