Question

Acrosome reaction in sperm is triggered by
A. Capacitation
B. Release of lysine
C. Influx of Na+
D. Release of fertilizin

Answer 1

Hint: Acrosome reaction occurs after the capacitation. There are rare cases where the release of sperm enzymes can cause severe inflammation in the male reproductive tract. Calcium ions are needed for the process.

Complete answer:
We shall study the process of sperm maturation. As spermiogenesis is the process of maturation of spermatozoa cells, after this the sperm undergoes capacitation. This process makes it possible for the male spermatozoa to fertilize the female egg. Capacitation occurs in the female reproductive tract. There occur some physiological changes in the sperm which will make the fertilization possible.

Now the step is when the sperm has reached the female egg and is just about to fertilize it. Sperm first needs to cross the plasma membrane of the female egg cell and then penetrate it. Penetrating a hard shell can cause a problem so to overcome this sperm undergoes acrosome reaction.

Now, what is an acrosome?
The acrosome is a cap-like structure present at the anterior (head) of the sperm. As soon as this part of sperm touches the female egg, the antigens present there get triggered. They release some enzymes which make it possible for the sperm to enter the egg cell.

The enzymes released are lysine agents called lysin. This will digest the vitelline coat of the sperm making the exposed part of it to interact with the egg cell.

So the answer is option B: release of lysine.

Note: Fertilizin is secreted from the cytoplasm of the egg cell so that the sperm could adhere to the egg. Fertilizin interacts with the anti-fertilizin of the sperm cell to initiate the reaction.
Calcium ions are required to process the acrosome reaction.