EVERYDAY SCIENCE

Detailed explanation-1: -These include changes to the egg’s membranes and outer coverings to prevent polyspermy and support the developing embryo, as well as resumption and completion of the meiotic cell cycle, mRNA poly-adenylation, translation of new proteins, and the degradation of specific maternal mRNAs and proteins.

Detailed explanation-2: -These changes include modifications to the extracellular matrix, to the plasma membrane, and to the secretory vesicles whose contents direct many of these events. In some species, these changes occur within minutes of fertilization, and are sufficiently dramatic so that they can be seen by the light microscope.

Detailed explanation-3: -If the egg is fertilized by a sperm as it travels down the fallopian tube, then pregnancy occurs. The fertilized egg attaches to the lining of the uterus. The placenta then develops. The placenta transfers nutrition and oxygen to the fetus from mother.

Detailed explanation-4: -The result of fertilization is a cell (zygote) capable of undergoing cell division to form a new individual. The fusion of two gametes initiates several reactions in the egg.