Your own cells wouldn't be a parasite, though they may be treated as such in autoimmune disorders, since they share your own DNA but other cells that do not share your DNA such as bacterial cells can be parasites - or not.
A virus is considered a parasite because it attaches to a cell and kills it.
A host cell is a cell that is infected or invaded by a virus, bacteria, or parasite that uses the host's cellular machinery to replicate or survive. In the context of parasitology, it refers to the cell that a parasite lives in or feeds on.
Intracellular parasite-- An organism which can only feed and live within the cell of a different animal.
An acellular obligatory parasite is a type of parasite that lacks cellular structure and relies on a host cell's machinery for survival and reproduction. Examples include viruses, viroids, and prions. These parasites cannot replicate or carry out metabolic functions independent of a host cell.
Parasite (not sure though)
A parasite is an organism that lives in or on a host cell. Parasites rely on the host for nutrients and can cause harm to the host they live in. Examples include Plasmodium, the parasite that causes malaria, and tapeworms.
Yes, at times a parasite is used to transfer DNA into the host cell. The parasite used is latent or inactivated so as not to hamper the normal functioning of the host cell. This method is generally not preferred now-a-days, since other options like DNA microinjection are gaining importance.
They can tell the difference because germs (parasites) have whats called Pili. These look like points or sticks coming off the parasite. White blood cells (WBC) use Pili to tell whether a cell is a parasite or not.
A virus is a parasite, that can only live on cells.
Chlamydia lives off its host cell. It's an obligate intracellular parasite.
Viruses require a host cell to replicate and reproduce. They inject their genetic material into the host cell where it instructs the cell to make new virus particles.
A virus or parasite that lives within an organism lacking a nucleus could infect a prokaryotic cell, such as a bacterium. In this case, the virus or parasite would utilize the host's cellular machinery to replicate and survive without the presence of a nucleus.