Question

nces Mailings Review View Help AaBboct AaB AaBbo . Lolormal 」1NoSpac Heading 1 Heading 2 Title Subtit y.a-圈플 ..|2 Paragraph Styles and 21. The two mechanizms for blocking polyspermy are 22. The cortical granule reaction that occurs after sperma faces with egg cell membrane serves as a slow block to polyspemmy. Which of the following events occur during a cortical reaction? A: Cortical reaction first releases proteases to remove the bounded sperm the egg cell membrane yet B: Cortical reaction then release other molecules including mucopolysaccharides that form a fertilization envelope and harden this fertilization eavelope C: The hardened fertilization envelope prevents further spern binding D: All of them that haven't fused with 23. TF. Besides restoring the genetic material, another function of fertilization is to activate the egg cell and initiate the processes that begin development shich depends on the activation of the 24. After sperm and egg cell fuse, there are waves of calcium that activate a set of events important for egg activ ation and development initiation. How are the calcium waves initiated and 25. Which of the following is NOT an erents activated by calcium wares after sperm and egg fuse? A: fast and slow block to polyspermy B: Initiation of DNA and protein syathesis that allow cell dirision to resume C: Activation of the recombiaed diploid nucleus D Akalinizatica of cytoplasm (causing increase in plH)

Answer 1

21. Slow block to polyspermy as well as fast block to polyspermy

22. D) all of them

23. False

24. At the time of activation of the egg, there would be an increase in the calcium levels in the cytosol which would activate the effector protein, referred to as calcineurin and CAMKII, initiating the transition at cellular level. As a result, the initial signal will be amplified as the target proteins would be phosphorylated. This would result in activation of the many different pathways inside the cell.