Developmental Biology — DU B.Sc. (Hons) Biological Sciences Previous Year Question Papers

(b) Explain the process of gastrulation and discuss the various morphogenetic movements associated with it, giving specific examples from different animals. 7 Q4. (a) Define placenta and describe its different types based on morphological and histological criteria, with suitable examples. 8 (b) How does gastrulation occur in the chick embryo? Discuss the role of the primitive streak and cell movements involved. 7 Q5. (a) Describe the function of pair-rule genes in establishing the segmented body plan in Drosophila, citing key gene examples. 8 (b) Describe the relationship between yolk content and cleavage type in animal embryos, with examples. 7 Q6. Write short notes on any three of the following: (3x5=15) (a) Extra embryonic membranes in birds (b) French Flag Model (c) Xenopus laevis as a Model Organism (d) Maternal effect genes (e) Techniques used in fate mapping