Following statement regarding to acrosome reaction in sea urchin.

A. Activation of the acrosome reaction serves as a barrier to intraspecies fertilizations.

B. The acrosome reaction is initiated by sulfate-containing polysaccharides in the egg jelly that bind to specific receptors located directly above the acrosomal vesicle on the sperm cell membrane.

C. These polysaccharides are often highly species specific, but egg jelly factors from one species of sea urchin generally activate the acrosome reaction in closely related species.

D. The elevated Ca2+ level in a relatively basic cytoplasm triggers the fusion of the acrosomal membrane with the adjacent sperm cell membrane, releasing enzymes that can lyse a path through the egg jelly to the vitelline envelope.

Which of the following statements are correct?

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#Question id: 15191

#Unit 8. Inheritance Biology

Genes that control coat color in mammals represent some of the best early examples of genes with multiple alleles exhibiting different phenotypes. A classic example is the C gene in hamsters. Three of the known alleles of this gene are C, c^k and c^a. Each supplies a different amount of black pigment to the coat hair. The phenotypes of three different homozygous strains are as follows.

Based on the concepts of dominance, determine whether ck and ca were dominant or recessive alleles by crossing the true-breeding sepia hamsters to true-breeding black hamsters. From the resulting F1 progeny phenotype, what would be the ratio of F2 phenotype

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#Question id: 23518

#General Aptitude

Which of the following is the transition layer between stratosphere and the mesosphere?

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#Question id: 1528

#Unit 4. Cell Communication and Cell Signaling

Mutation of p53 is described as a dominant-negative mutation. Which of the following statement is correct regarding to the mechanism by which this mutation causes the dominant-negative phenotype?

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#Question id: 15543

#Unit 8. Inheritance Biology

In Benzer's intragenic mapping experiments, what event was required to allow production of infectious phage from rII mutants?

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#Question id: 11473

#Unit 7. System Physiology – Animal

Lateral inhibition via horizontal cells in the mammalian retina ________.