Fertilization in sea urchin eggs involves Ca2+ release from the endoplasmic reticulum for cortical granule reactivation. The major molecule responsible for releasing Ca2+ from intracellular stores is (1) zonapellucida glycoproteins (2) protamines (3) inositol 1, 4, 5-trisphosphate (4) N-acetylglucosaminidasev Introduction Sea urchin fertilization is initiated by a rapid and transient release of calcium ions (Ca2+) […]
During fertilization in mammals proteins lzumo and Juno are required for recognition of sperm and egg. lzumo and Juno are found specifically in sperm and egg, respectively. Which one of the following in vivo experiments will demonstrate that lzumo and Juno interact with each other? (1) If sperms from a male mouse where lzumo has […]
52. Vascular endothelial (VE)-cadherin is an important cell adhesion molecule for endothelial cells. Endothelial cells that are unable to express VE-cadherin still can adhere to one another via N-cadherin (neural cadherin), but these cells do not survive. Which of the following is the most appropriate reason for this? (1) N-cadherin uses VE-cadherin as co-receptor for […]
51. Temporal expression of N-cadherin is extremely important during early development of the mammalian embryos. Accordingly, which one of the following statements about N-cadherin is true? (1) Injection of N-cadherin antibodies just prior to condensation of mesenchymal cells will aid cartilage formation. (2) Presence of N-cadherin just prior to condensation will facilitate nodule formation and […]
Cadherins mediate Ca2+-dependent cell-cell adhesion and play an important role in embryonic development by changing the adhesive properties of cell. Aggregation of nerve cells to form an epithelium is correlated with the appearance of N-cadherins on cell surface and vice versa. N-CAM (neural cell adhesion molecules) belongs to lg-SF (immunoglobulin super family) and involved in […]
Preventing the blocking action of Patched protein leads to activation of Cos-2, which dissociates itself from microtubules, activates Ci/Gli which binds to CBP (CREB- binding protein) and promotes transcription of target genes. Which one of the following treatment of cells will mostly prevent Ci/Gli activated transcription in thecells? (1) Small molecules which target Frizzled. (2) […]
48. Which one of the following graphs represents the relative expression of proteins of Wnt-activated signaling cascades involved during development of an embryo? The relative expression of proteins in Wnt-activated signaling cascades during embryo development typically shows distinct patterns based on the specific Wnt pathway involved—canonical (β-catenin dependent) or non-canonical pathways (planar cell […]
47. Activation of the Wnt signal transduction pathway is extremely important during early development. Of the various pathways, which one of the following is most likely to induce cytoskeletal changes, like cell shape and movement? Activation of the non-canonical Wnt/Planar Cell Polarity (PCP) pathway is most likely to induce cytoskeletal changes like cell shape and […]
46. Of the following signaling processes which one is NOT involved in cellular movement or cytoskeletal changes? Of the signaling processes involved in cellular movement or cytoskeletal changes, some pathways are directly related to the regulation of cytoskeletal dynamics, cell motility, and shape, while others are not primarily involved in […]
45. Intracellular transport and cytoskeletal organization of a cell is regulated by nucleotide exchange of different small molecular weight GTPases of Ras super family. Overexpression of which of the following GTPase modulates the actin-cytoskeleton of HeLa cells? (1) Ran in GDP bound form (2) Ran in GTP bound form (3) Rho in GTP bound form […]
