Strep throat is a contagious disease caused by infection with streptococcal bacteria, which causes inflammation and swelling of the mucous membranes lining the back of the throat and the tonsils.trep throat is a contagious disease caused by infection with streptococcal bacteria, which causes inflammation and swelling of the mucous membranes lining the back of the throat and the tonsils.
Once an egg cell is fertilized by a sperm, it will divide and become an embryo. In the embryo, there are stem cells that are capable of becoming all of the various cell types of the human body. For research, scientists get embryos in two ways. Many couples conceive by the process of in vitro fertilization. In this process, a couple's sperm and eggs are fertilized in a culture dish.
Formation of male and female pronuclei are the final step in the fertilization process. Pronuclei contain the genetic material (DNA) from the sperm and the egg. With pronuclei formation, the fertilization process is completed. A fertilized egg is also called a zygote, a 1 cell embryo or a 2 pronuclear embryo.