All viruses have is a protein coat and a core of genetic material, either RNA or DNA. Unlike bacteria, viruses can't survive without a host. They can only reproduce by attaching themselves to cells. Unlike bacteria, most viruses do cause disease, and they're quite specific about the cells they attack.
The classification is in this order: Kingdom, Phylum, Class, Order, Family, Genus Species.
The kingdom is the largest group, it contains the largest number of organisms who are the least related.
The species is the smallest group, it contains the least number of organisms who are closely related.
As you go down, from "Kingdom", species become more closely related.
So species in the same family are MORE closely related than species in the same class.
<span>Transcription is the first step of gene expression, in which a particular segment of DNA is copied into RNA (especially mRNA) by the enzyme RNA polymerase. Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language.
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