#Question id: 5663
#Unit 5. Developmental Biology
Following statements are related to slow block to polyspermy in mammals.
A. A First slow block to polyspermy comes When the cortical granules fuse with the egg cell membrane, they release protein-digesting enzymes which is called as ovastacin that modify the zona pellucida proteins.
B. A second slow block to polyspermy comes from the so-called zinc spark, the release of billions of zinc ions that is induced by the entry of the first sperm, these released zinc ions are seen to bind to the egg cell membrane form a “zinc shield” that prevents further sperm entry.
C. A third slow block to polyspermy occurs at the level of the egg cell membrane and involves Juno.
Which of the following is incorrect?
#Question id: 5664
#Unit 5. Developmental Biology
Following statements are regarding to gamete fusion and the prevention of polyspermy in mammals.
A. In mammals, it is not the tip of the sperm head that makes contact with the egg but the side of the sperm head.
B. The junction between the inner acrosomal membrane and the sperm cell membrane is called the acrosomal region, and this is where membrane fusion between sperm and egg begins.
C. Sperm-egg fusion appears to involve several proteins, two of which are Izumo, in the oocyte membrane, and Juno, in the acrosomal membrane.
D. These fusion proteins bind together and appear to recruit other proteins to make an adhesion and fusion complex.
Which of the following statements are correct?
#Question id: 5665
#Unit 5. Developmental Biology
Following statements are regarding to cortical granule reaction.
A. To initiating the slow block to polyspermy the release of Ca2+ that occurs when the sperm enters the egg is critical for activating the egg’s metabolism and initiating development
B. Calcium ions release the inhibitors from maternally stored messages, allowing these mRNAs to be translated
C. Calcium ions are not release the inhibition of nuclear division, thereby allowing cleavage to occur.
D. Udx1, the enzyme responsible for the reduction of oxygen to crosslink the fertilization envelope, is also NADPH-dependent
E. The fertilization envelope is elevated from the cell membrane by glycosaminoglycans which provides support for the blastomeres during cleavage
Which of the following combinations are correct?
#Question id: 5666
#Unit 5. Developmental Biology
When the extracellular side of the receptor binds resact, it activates latent guanylyl cyclase in the cytoplasmic side of the receptor. Active guanylyl cyclase causes the sperm cell to produce more cyclic GMP (cGMP), this compound_____
#Question id: 5667
#Unit 5. Developmental Biology
There may be an important connection between sperm translocation and capacitation. Which of the following option is correct explanation of above statement?
#Question id: 5668
#Unit 5. Developmental Biology
Following statements are made in relation to the five widely recognized stages of Arabidopsis embryogenesis:
A. The fusion of haploid egg and sperm takes place in zygotic stage
B. Rapid cell division in two regions on either side of the future shoot apex forms globular stage
C. The cell elongation throughout the embryo axis and further development result in Torpedo stage
D. The embryo loses water and becomes metabolically inactive in the torpedo stage
Which combination of the above statements is correct?