Tuberculosis and HIV

how HIV causes AIDs

HIV infects human cells (T helper cells).

It has viral attachment proteins that are complimentary to receptors on the cell surface membrane of T helper cell. These receptors are called CD4 receptors

and are found on the cell surface membrane of T helper cells. Then

the lipid envelope of the HIV fuses with the cell surface membrane of

the T helper cell releasing the protein capsid containing the RNA

strand and the enzymes reverse transcriptase and integrase.

Reverse transcriptase catalyses the reverse transcription of the viral

RNA to complimentary DNA called cDNA. The cDNA molecule is

single stranded and so cannot be attached to the human chromosome.

Therefore the host cells DNA polymerase catalyses the formation of a

complimentary DNA strand to the cDNA. The double stranded viral

DNA can now be attached to the human DNA by action of integrase

enzyme.

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