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

Tooth in mammals develops from the

  1. endoderm

  2. ectoderm

  3. memoderm

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

Teeth develop from ectoderm (specifically oral ectoderm) interacting with neural crest-derived mesenchyme. The enamel organ forms from ectoderm, while dentin and pulp form from mesenchyme. Endoderm gives rise to internal organs, and 'memoderm' appears to be a misspelling.

Multiple choice

Mammalian embryo is directly surrounded by

  1. amniotic cavity

  2. allantoic cavity

  3. primary digestive cavity

  4. yolk sac cavity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The amniotic cavity is the closed sac between the embryo and the amnion, containing the amniotic fluid. The amniotic cavity is formed by the fusion of the parts of the amniotic fold, which first makes its appearance at the cephalic extremity and subsequently at the caudal end and sides of the embryo.

Multiple choice

Adventive embryony leads to the formation of

  1. one embryo

  2. two embryos

  3. many embryos

  4. half embryo

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

Adventive embryony is a type of polyembryony where embryos develop from diploid sporophytic cells (like nucellus or integuments), often resulting in many embryos within a single seed.

Multiple choice

When an embryo arises from the integument of the ovule, the phenomenon is known as

  1. polyembryony

  2. adventive embryony

  3. half embryony

  4. extra embryony

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

Adventive embryony refers to the development of an embryo directly from the diploid cells of the integument or nucellus. Polyembryony is a broader term for the presence of more than one embryo in a seed, which can include adventive embryony as a specific type.

Multiple choice

In which of the following species, monosporic embryo sac is found?

  1. Allium

  2. Oenothera

  3. Adoxa

  4. Plumbago

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

Oenothera type embryo sac development is a classic example of monosporic development, where only one megaspore nucleus participates in the formation of the embryo sac. Allium and Adoxa are examples of bisporic and tetrasporic development, respectively.

Multiple choice

The correct sequence of various sub layers in the epidermis of vertebrates integument starting from outside is

  1. stratum germinativum, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

  2. stratum germinativum, stratum corneum, stratum granulosum, stratum lucidum

  3. cuticle, endodermis, dermis, hypodermis

  4. stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum germinativum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The epidermis of mammalian skin is organized from the surface inward as: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum germinativum (basale).

Multiple choice

Collenchyma mainly forms _____.

  1. hypodermis

  2. epidermis

  3. endodermis

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

Collenchyma is a supporting tissue in plants that is typically found in the hypodermis of stems and leaves, providing structural support while allowing for growth.

Multiple choice

The Polygonum type of embryo sac is

  1. bisporic eight-nucleate

  2. monosporic four-nucleate

  3. tetrasporic sixteen-nucleate

  4. monosporic eight-nucleate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Polygonum type of embryo sac is the most common type in angiosperms. It develops from a single megaspore (monosporic) and undergoes three rounds of mitosis to form eight nuclei.