BIO342H5 Chapter Notes - Chapter 1: Mutation Rate, Integrase, Sub-Saharan Africa

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1. 1- the natural history of the hiv/aids epidemic. Hiv initiates its replication phase by latching onto two proteins on the surface of a host cell. Hiv then binds to two surface proteins on the target cell called cd4 and coreceptor. In hiv and other retroviruses, flow of genetic information is different than in cells and in viruses with dna genomes. In retroviruses, genetic information does not follow the familiar route from. Dna to mrna to proteins: instead it flows from rna to dna, then to mrna to proteins. How does hiv cause aids: hiv parasitizes immune system cells, particularly helper t cells. After a long battle against the virus, the immune system"s supply of helper t cells is badly depleted. In addition, the immune system mobilizes against the infection and killer t cells begin to target host cells infected with hiv: the host"s cd4 t cell counts recover somewhat.