Question

Suppose a sperm cell fertilizes an oocyte. A minute later, a 2nd sperm cell propels itself against the same oocyte. The chromosomes from the 2nd sperm cell will not normally function in the resulting embryo because:_______________.

Answer 1

Answer:

The second sperm entry is blocked by the fertilized oocyte.

Explanation:

An ovum prevents polyspermy by two mechanism:

1. When the first sperm fuses with the oocyte then rapid depolarization of egg's plasma membrane takes place which prevents other sperms to fuse with the egg.

2. The fusion of sperm cause an increase in the amount of calcium ion in the cytosol of egg. This higher calcium level activates the development of egg which results in the change in the structure of the egg's outer layer. The outer layer(zona pellucida) becomes hard and prevent the entry of other sperms.

So the chromosomes from the 2nd sperm cell will not normally function in the resulting embryo because the fertilized oocyte block the entry of other sperms.