Many animal viruses have a membranous envelope with glycoprotein that
bind to specific receptor molecules on the surface of a host cell.
An RNA virus. The viral RNA genome functions as a template for
synthesis of complementary RNA strands. The complementary RNA can be
used to make copies of viral genome RNA, or can serve as mRNA, which
is translated into capsid proteins and glycoproteins of the viral
HIV, a retrovirus.
The Human Immunodeficiency Virus (HIV) is a retrovirus.
It has the enzyme reverse transcriptase to copy the RNA genome into
DNA, which is integrated into the host genome as a provirus, where it
remains a permanent resident.
The host's RNA polymerase transcribes the proviral DNA into RNA
molecules, which may function both as mRNA for synthesis of viral
proteins and as new viral genomes.
AZT and reverse transcriptase
Review and exercise: