Table of Contents
NET SLET: Life Science (Embryology)
This set of 50 hard-level multiple-choice questions (MCQs) on Embryology is crafted for CSIR NET SLET Life Sciences aspirants preparing for the 2025 examination. Focused on advanced concepts like molecular regulation, signaling pathways, and experimental embryology, these MCQs aim to challenge and enhance understanding of developmental biology. Hope this set will benefit you.
These MCQs are intended for educational purposes to assist NET SLET Life Sciences preparation. While carefully designed to align with the syllabus, they are not officially endorsed by CSIR or any examination authority. Students are advised to cross-reference with standard textbooks and consult mentors for comprehensive preparation. Any errors are unintentional, and for official guidelines, refer to NET SLET resources.
NET SLET- 50 MCQs (Life Science) Embryology
1. Which molecular mechanism primarily prevents polyspermy in sea urchin eggs?
(a) Release of cortical granules triggering zona pellucida hardening
(b) Activation of sodium-potassium ATPase
(c) Depolarization of the egg membrane
(d) Inactivation of sperm receptors
Answer: (c) Depolarization of the egg membrane
2. In Xenopus, the Nieuwkoop center is critical for inducing the formation of:
(a) Ectoderm
(b) Mesoderm
(c) Endoderm
(d) Trophectoderm
Answer: (b) Mesoderm
3. The role of the Spemann-Mangold organizer in amphibian embryos is primarily mediated by which signaling pathway?
(a) Hedgehog
(b) Wnt
(c) BMP inhibition
(d) Notch
Answer: (c) BMP inhibition
4. In Drosophila, the bicoid gene is responsible for establishing:
(a) Dorsal-ventral axis
(b) Anterior-posterior axis
(c) Left-right axis
(d) Terminal patterning
Answer: (b) Anterior-posterior axis
5. Which transcription factor is essential for trophoblast differentiation in mammalian embryos?
(a) Oct4
(b) Cdx2
(c) Sox2
(d) Nanog
Answer: (b) Cdx2
6. The process of epithelial-to-mesenchymal transition (EMT) during gastrulation is regulated by:
(a) Snail and Twist transcription factors
(b) Pax6 and Sox9
(c) MyoD and GATA4
(d) Runx2 and FoxP3
Answer: (a) Snail and Twist transcription factors
7. In C. elegans, the anchor cell induces vulval development through which signaling pathway?
(a) Wnt
(b) Notch
(c) EGF/Ras
(d) TGF-β
Answer: (c) EGF/Ras
8. The formation of the primitive streak in amniotes is initiated by the activity of which gene?
(a) Brachyury (T)
(b) Goosecoid
(c) Chordin
(d) Noggin
Answer: (a) Brachyury (T)
9. In zebrafish, the shield region is homologous to which structure in amphibians?
(a) Hensen’s node
(b) Dorsal lip of blastopore
(c) Ventral lip of blastopore
(d) Animal pole
Answer: (b) Dorsal lip of blastopore
10. Which of the following is a key regulator of mesoderm induction in Xenopus embryos?
(a) Activin
(b) Sonic hedgehog
(c) Retinoic acid
(d) Delta
Answer: (a) Activin
11. The zone of polarizing activity (ZPA) in limb development is primarily associated with the expression of:
(a) Sonic hedgehog (Shh)
(b) FGF8
(c) Wnt7a
(d) BMP4
Answer: (a) Sonic hedgehog (Shh)
12. In mammals, the inner cell mass (ICM) of the blastocyst gives rise to:
(a) Trophoblast
(b) Embryo proper
(c) Extraembryonic membranes
(d) Placenta
Answer: (b) Embryo proper
13. Which gene mutation in Drosophila leads to the formation of two posterior ends in the embryo?
(a) Bicoid
(b) Nanos
(c) Hunchback
(d) Kruppel
Answer: (b) Nanos
14. The process of somitogenesis in vertebrates is regulated by a molecular clock involving which pathway?
(a) Notch-Delta
(b) Wnt
(c) Hedgehog
(d) BMP
Answer: (a) Notch-Delta
15. In avian embryos, Hensen’s node is responsible for inducing:
(a) Neural plate
(b) Somites
(c) Endoderm
(d) Extraembryonic mesoderm
Answer: (a) Neural plate
16. Which protein inhibits BMP signaling in the Spemann organizer to promote neural induction?
(a) Chordin
(b) Cerberus
(c) Dickkopf
(d) Lefty
Answer: (a) Chordin
17. In sea urchins, the micromeres at the vegetal pole are critical for specifying:
(a) Ectoderm
(b) Endoderm
(c) Mesoderm
(d) Archenteron
Answer: (c) Mesoderm
18. The role of the apical ectodermal ridge (AER) in limb development is to secrete:
(a) Sonic hedgehog
(b) Fibroblast growth factors (FGFs)
(c) Bone morphogenetic proteins (BMPs)
(d) Wnt proteins
Answer: (b) Fibroblast growth factors (FGFs)
19. In mammals, the process of X-chromosome inactivation in female embryos is mediated by:
(a) Xist RNA
(b) Tsix RNA
(c) SRY gene
(d) Sox9
Answer: (a) Xist RNA
20. The gene responsible for specifying the dorsal side of the Drosophila embryo is:
(a) Dorsal
(b) Bicoid
(c) Nanos
(d) Gurken
Answer: (a) Dorsal
21. In Xenopus, the maternal factor VegT is critical for the specification of:
(a) Ectoderm
(b) Mesoderm and endoderm
(c) Neural plate
(d) Trophectoderm
Answer: (b) Mesoderm and endoderm
22. The segmentation gene ‘engrailed’ in Drosophila is expressed in:
(a) Anterior compartment of segments
(b) Posterior compartment of segments
(c) Entire segment
(d) Intersegmental boundaries
Answer: (b) Posterior compartment of segments
23. Which signaling pathway is critical for left-right asymmetry in vertebrate embryos?
(a) Notch
(b) Nodal
(c) Hedgehog
(d) Wnt
Answer: (b) Nodal
24. In chick embryos, the regression of Hensen’s node leads to the formation of:
(a) Neural tube
(b) Somites
(c) Notochord
(d) Primitive streak
Answer: (c) Notochord
25. The process of neurulation in vertebrates is initiated by the expression of:
(a) Pax3 and Pax7
(b) Sox2 and Sox3
(c) Noggin and Chordin
(d) Brachyury
Answer: (b) Sox2 and Sox3
26. In C. elegans, the P-granules are essential for specifying:
(a) Germline cells
(b) Somatic cells
(c) Muscle cells
(d) Neurons
Answer: (a) Germline cells
27. The role of retinoic acid in vertebrate development is primarily associated with:
(a) Anterior-posterior patterning
(b) Dorsal-ventral patterning
(c) Left-right asymmetry
(d) Neural crest migration
Answer: (a) Anterior-posterior patterning
28. In Drosophila, the gap gene ‘hunchback’ is activated by:
(a) Bicoid
(b) Nanos
(c) Dorsal
(d) Gurken
Answer: (a) Bicoid
29. The process of convergent extension during gastrulation is driven by:
(a) Cell adhesion molecules
(b) Planar cell polarity pathway
(c) Apical constriction
(d) Cytoskeletal rearrangements
Answer: (b) Planar cell polarity pathway
30. In mammals, the formation of the blastocyst involves the differentiation of:
(a) Inner cell mass and trophoblast
(b) Epiblast and hypoblast
(c) Primitive endoderm and ectoderm
(d) Mesoderm and ectoderm
Answer: (a) Inner cell mass and trophoblast
31. The gene ‘goosecoid’ is expressed in which region during amphibian gastrulation?
(a) Ventral lip of blastopore
(b) Dorsal lip of blastopore
(c) Animal pole
(d) Vegetal pole
Answer: (b) Dorsal lip of blastopore
32. In zebrafish, the mutation in the ‘one-eyed pinhead’ gene disrupts:
(a) Mesoderm formation
(b) Endoderm specification
(c) Neural induction
(d) Somite segmentation
Answer: (b) Endoderm specification
33. The primary role of the T-box gene Tbx5 in vertebrate limb development is to specify:
(a) Forelimb identity
(b) Hindlimb identity
(c) Limb outgrowth
(d) Digit formation
Answer: (a) Forelimb identity
34. In Drosophila, the pair-rule gene ‘even-skipped’ is expressed in:
(a) Every segment
(b) Alternate segments
(c) Anterior half of each segment
(d) Posterior half of each segment
Answer: (b) Alternate segments
35. The process of germ cell migration in vertebrates is guided by the chemokine:
(a) SDF-1
(b) BMP4
(c) Wnt3a
(d) FGF8
Answer: (a) SDF-1
36. In mammals, the specification of the epiblast is dependent on the expression of:
(a) Nanog
(b) Cdx2
(c) GATA6
(d) Eomesodermin
Answer: (a) Nanog
37. The role of the ‘noggin’ gene in neural induction is to:
(a) Activate BMP signaling
(b) Inhibit BMP signaling
(c) Promote Wnt signaling
(d) Inhibit Notch signaling
Answer: (b) Inhibit BMP signaling
38. In sea urchins, the nuclear localization of β-catenin is critical for specifying:
(a) Ectoderm
(b) Endoderm
(c) Mesoderm
(d) Archenteron
Answer: (b) Endoderm
39. The gene ‘Pax6’ is essential for the development of which structure in vertebrates?
(a) Heart
(b) Eye
(c) Limb
(d) Kidney
Answer: (b) Eye
40. In Drosophila, the maternal effect gene ‘torso’ is involved in specifying:
(a) Anterior-posterior axis
(b) Terminal regions
(c) Dorsal-ventral axis
(d) Segment polarity
Answer: (b) Terminal regions
41. The process of heart looping in vertebrates is regulated by:
(a) Nodal and Pitx2
(b) Sonic hedgehog
(c) FGF8
(d) Wnt3a
Answer: (a) Nodal and Pitx2
42. In Xenopus, the ‘cerberus’ gene encodes a secreted protein that inhibits:
(a) BMP, Wnt, and Nodal signaling
(b) Notch and Hedgehog signaling
(c) FGF and TGF-β signaling
(d) Wnt and Notch signaling
Answer: (a) BMP, Wnt, and Nodal signaling
43. The role of the ‘engrailed’ gene in vertebrate limb development is to:
(a) Define the anterior-posterior boundary
(b) Promote limb outgrowth
(c) Specify digit identity
(d) Induce AER formation
Answer: (a) Define the anterior-posterior boundary
44. In C. elegans, the lin-3 gene encodes a ligand for which signaling pathway?
(a) Notch
(b) EGF
(c) Wnt
(d) Hedgehog
Answer: (b) EGF
45. The process of digit formation in vertebrate limbs is regulated by:
(a) Apoptosis in interdigital regions
(b) Proliferation of AER cells
(c) BMP inhibition
(d) Wnt activation
Answer: (a) Apoptosis in interdigital regions
46. In Drosophila, the homeotic gene ‘Ultrabithorax’ is responsible for specifying:
(a) Head segments
(b) Thoracic segments
(c) Abdominal segments
(d) Terminal segments
Answer: (c) Abdominal segments
47. The role of the ‘FGF10’ gene in lung development is to:
(a) Induce branching morphogenesis
(b) Specify alveolar cells
(c) Promote neural induction
(d) Inhibit mesoderm formation
Answer: (a) Induce branching morphogenesis
48. In mammals, the formation of the neural crest is dependent on the interaction between:
(a) BMP and Wnt signaling
(b) Notch and Hedgehog signaling
(c) FGF and TGF-β signaling
(d) Nodal and BMP signaling
Answer: (a) BMP and Wnt signaling
49. The gene ‘Hoxa13’ is critical for the development of which structure in vertebrates?
(a) Forelimbs
(b) Hindlimbs
(c) Genital tubercle
(d) Cranial nerves
Answer: (c) Genital tubercle
50. In zebrafish, the ‘no tail’ (ntl) gene is a homolog of which vertebrate gene?
(a) Brachyury
(b) Goosecoid
(c) Chordin
(d) Noggin
Answer: (a) Brachyury
MOCK TEST SERIES
| Mock Test Series On General Science (TET/ADRE/RRB/SSC/APSC/Assam Police Written Exam Special) – Click Here | Click Here |
| Mock Test Series On Assam History (TET/ADRE/RRB/SSC/APSC/Assam Police Written Exam Special) – Click Here | Click Here |
| Mock Test Series On Indian History (TET/ADRE/RRB/SSC/APSC/Assam Police Written Exam Special) | Click Here |
| Mock Test Series On Assam Geography (TET/ADRE/RRB/SSC/APSC/Assam Police Written Exam Special) | Click Here |
| Mock Test Series On Assam Economy (TET/ADRE/RRB/SSC/APSC/Assam Police Written Exam Special) | Click Here |
| Mock Test Series On Movies & Awards (TET/ADRE/RRB/SSC/APSC/Assam Police Written Exam Special) | Click Here |