MCQ Bank
The ............. lies at the border between the area pellucida and the area opaca.
- A) Marginal area
- B) Marginal belt
- C) Marginal zone
- D) Marginal zone or marginal belt
A ........ is a group of cells located at the anterior end of the primitive streak in a developing gastrula.
- A) Primitive streak
- B) Primtive pit
- C) Primtive knot
- D) Primitive groove
The centre of the node contains a funnel-shaped depression through which cells can pass into the blastocoels, called -----------------
- A) Primtive streak
- B) Primtive knot
- C) Hensen's node
- D) Primtive pit
During gastrulation in fish, a thickening occurs throughout the margin of the epibolizing blastoderm. This thickening is called the.........
- A) Embryonic layer
- B) Germinal ring
- C) Germ layer
- D) Germ ring
During gastrulation in the avian embryo, ------------serves as an opening through which migrating cells pass into the blastocoel.
- A) Neural groove
- B) Neural plate
- C) Primitive groove
- D) Primitive streak
Cells migrating through ............ pass down into the blastocoel and migrate anteriorly, forming foregut, head mesoderm, and notochord.
- A) Hensen's node
- B) Primitive streak
- C) Blastopore
- D) Primitive gut
In fish eggs, cleavage occurs only in the ...... region at the animal cap of the egg.
- A) Blastodisc
- B) Blastocoel
- C) Blastoderm
- D) Blastocyst
In birds, cleavage occurs only in the ........, located at the animal pole of the egg cell.
- A) Blastoderm
- B) Blastodisc
- C) Blastocoel
- D) albumin
The Chordamesoderm is a specific type of mesoderm that will give rise to the ........ in developing embryos of fish.
- A) Notochord
- B) Muscles
- C) Somites
- D) Neural tube
In mammals, oocyte is released from ovary and swept by _________into oviduct.
- A) Villi
- B) Pili
- C) Thread like structures
- D) Fimbriae
In fish, some of the nuclei will move vegetally, staying ahead of the blastoderm margin, to form .........
- A) Yolk Syncytial Layer
- B) External YSL
- C) Medial YSL
- D) Internal YSL
Cleavages in... .... are among the slowest in the animal kingdom, about 12–24 hours apart.
- A) Amphibians
- B) Birds
- C) Mammals
- D) Fishes
The streak is first visible in birds as a thickening of the ________at the posterior region of the embryo, just anterior to Koller's sickle.
- A) Hypoblast
- B) Neuroblast
- C) Epiblast
- D) Ectoderm
The cells of both the epiblast and hypoblast intercalate on the future dorsal side of the embryo to form a localized thickening, the --------------
- A) Germ ring
- B) Neural tube
- C) Embryonic shield
- D) Yolk syncytial layer
During mammalian cleavage the trophoblast cells secrete fluid into the morula to create a blastocoel, this process is called -----------------
- A) Compaction
- B) Cavitation
- C) Contraction
- D) Capacitation
The ---------- consists of a small group of internal cells surrounded by a larger group of external cells.
- A) Gastrula
- B) Neurula
- C) Blastula
- D) Morula
During gastrulation of the avian embryo, the two-layered blastoderm (epiblast and hypoblast) is joined together at the margin of the area opaca, and the space between the layers forms a .........
- A) Blastodisc
- B) Blastocoel
- C) Blastocyte
- D) Blastoderm
The primitive streak is the major structural characteristic of-------------------
- A) Fish
- B) Molluscs
- C) Avian
- D) Arthropods
Fraternal twins are the result of ..... separate fertilization events.
- A) Three
- B) Four
- C) Single
- D) Two
The ..........induces the formation of the midbrain, hindbrain, and spinal cord.
- A) Mesoderm
- B) Prechordal mesoderm
- C) Intermediate mesoderm
- D) Chordamesoderm