The collection of diseases that arise because of HIV infection is called acquired immune deficiency syndrome, or AIDS. HIV is classified as a lentivirus ("lenti" means "slow") because the virus takes a long time to produce symptoms in an infected individual.
Hiv Life Cycle: Entering Cells
Like a typical virus, HIV infects a cell and appropriates the host's cellular components and machinery to make many copies of itself. The new viruses then break out of the cell and infect other cells. HIV stores its genetic information on an RNA molecule rather than a DNA chromosome. This is a distinguishing characteristic of retroviruses, which are viruses that must first convert their RNA genomes into DNA before they can reproduce.
Each HIV virion (viral particle) is a small sphere composed of several layers. The external layer is a membrane coat, or envelope, obtained from the host cell in which the particle was made. Underneath this membrane liesa shell made from proteins, called a nucleocapsid. Inside the protein shell are two copies of the virion's RNA genome and three kinds of proteins, which are used by the virion to establish itself once inside the cell that it infects.
Two proteins, called gp120 and gp41, enable the virion to recognize the type of cell to enter.
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