Now, once that binding takes place and the HIV recognizes this specific type of human cell, we have the fusion taking place, the fusion between this lipid rich layer found on the virus and the cell membrane of that human host cell. So in three, once bound, the lipid rich envelope of the virus fuses with the plasma membrane of the host human cell injecting the contents, including the proteins as well as the single RNA molecules into the cytoplasm of that cell. And next we move on to step number four. In step number four, right within the cytoplasm of that human cell, these reverse transcriptase enzymes basically transcribe the RNA into DNA and we form the viral double stranded DNA as shown in blue. So we form one and two strands and then they basically fuse to form our double stranded DNA, the viral double stranded DNA. Now, in step five we have the viral double stranded DNA, then basically travels into the nucleus of that cell and in the nucleus of that cell, another special type of enzyme known as retroviral integrates or simply integrates, acts to basically integrate or incorporate that viral double stranded DNA shown in blue into the DNA genome of that human cell.