Is a fertilized human ovum (a zygote) equivalent to a bacteria or virus?”
A virus is just a length of DNA with a protective coating. A zygote is much more complex than that. A virus can last for a long time outside a host, but a zygote cannot. A bacterium is very simple, many with a single strand of DNA. A zygote cell and a bacteria cell may look similar under a microscope, but their potential is much different and their future lifecycle is much different. There is a lot of complicated chemistry going on inside a fertilized egg as DNA is distributed and combined, which is very different from the mitosis going on in a bacterium. The zygote will eventually split via mitosis, but these cells will not normally separate and become independent like bacteria will. Yes, a zygote may look similar to a bacteria at first glance, but its chemistry is much different, and its future will definitely be much different. They are not equivalent. I hope this helps.
