Following statements are regarding to recognition of sperm by mammalian zona pellucida.

A. Sperm that have undergone the acrosome reaction bind directly to zona protein ZP2 and begin making a channel toward the oocyte.

B. Sperm with an intact acrosome bind to ZP2; they undergo the acrosome reaction on the zona pellucida and then transfer their binding to ZP3.

C. When a sperm reaches the oocyte and fuses with it, the cortical granules release proteins that digest portions of ZP2 and ZP3, making them nonfunctional and prevent polyspermy.

D. When a sperm reaches the oocyte and fuses with it, the cortical granules release proteins that digest ZP3 only, not ZP2 because ZP2 involve in the process of slow block to polyspermy.

Which of the above statements are correct?

#Question id: 4991

#Unit 11. Evolution and Behavior

Which of these fly organs, as they exist in current fly populations, best fits the description of an exaptation?

#Question id: 26932

#Unit 10. Ecological Principles

#Question id: 127

#Unit 1. Molecules and their Interaction Relevant to Biology

Which two organelles are responsible for producing phospholipids and sphingolipids?

#Question id: 5199

#Unit 11. Evolution and Behavior

For mapping studies of genomes, most of which were far along before 2000, the 3 -stage method was often used. Which is the usual order in which the stages were performed, assuming some overlap of the three?

#Question id: 10536

#Unit 6. System Physiology – Plant

Hormonal interactions contribute to plant–insect herbivore interactions such as— ethylene, salicylic acid, and jasmonic acid. In particular, ethylene appears to play an important role in this context, what will be the effect of ethylene when is applied alone and when is applied with other amino acids?

a) ethylene applied together with JA it seems to reduces defense responses

b) Ethylene appears to applied alone to plants, ethylene has little effect on defense-related gene activation

c) when ethylene applied together with JA it seems to enhance JA responses or defense responses are significantly increased

d) Ethylene appears to applied alone to plants, ethylene has more effect on defense-related gene activation

Which of the following combination is correct about ethylene effects?