simplified diagram of HIV replication (life cycle). The above image is 500 pixels across, the original measures 3,600 pixels across.
Human Immunodeficiency Virus (HIV) particle (upper right) attaches to cell surface. The viral envelope merges with the cell plasma membrane (middle) releasing the matrix shell and core (purple bullet-shaped structure containing the viral genome) into the cell. The viral RNA (yellow string-like structure in core) is converted into viral DNA (red string-like structure in core) by the enzyme reverse transcriptase (green sphere). The viral genome is delivered to the nucleus (brownish sphere at bottom) and enters through a nuclear pore (flower-like opening). Once inside the nucleus, the viral DNA joins (integrates) with the host cell DNA. The viral DNA then directs the production of viral RNA which exits the nucleus through nuclear pores. Some viral RNA goes to form a new viral genome (yellow lump attached to underside of cell membrane at left) while other viral RNA directs the production of new viral proteins via ribosomes (3 brown spherical objects in middle of cell). The new viral components (genome + proteins) assemble at the cell surface (left) and a new virus particle buds from the cell (upper left).