2.4.6: HIV and AIDS Flashcards
describe the structure of HIV
reverse transcriptase, 2 RNA strands, protein capsid, attachment proteins (of host cell), double lipid membrane (membrane of host cell)
what is the role of the reverse transcriptase in HIV
in order to replicate, virus’ RNA needs to transcribe into DNA, so it can insert its DNA into the host cell’s nucleus
what cells does HIV infect
T helper cells ONLY
Describe and explain the sequence of the HIV lifecycle
1 - binding - HIV attached to receptor proteins on surface to T helper cell
2 - Fusion - HIV membrane fuses with T helper cell membrane allowing entry of viral capsid and contents
3 - Reverse transcription - HIV uses reverse transcriptase to make viral DNA using its viral RNA as a template
4 - Integration - viral DNA enters T helper cell’s nucleus and becomes inserted into T helper cell’s DNA
5 - Activation - virus uses T helper cells machinery to synthesise viral proteins and viral RNA
6 - Assembly - viral proteins and RNA synthesised by T helper cell move towards the cell membrane and begin to assemble into HIV
7 - Budding - HIV pushes itself out of T helper cell taking a section of the T helper cell’s membrane with it
The first part of the HIV lifecycle - binding, fusion, reverse transcription, integration - happens for decades, what does this result in
when T helper cells go through clonal expansion, all daughter T helper cells have the viral DNA in them
the second part of the HIV lifecycle - activation, assembly, budding - happens at any point in time, what does this result in
T helper cells decrease in number as their cell membrane is no longer, and so no activation of B cells or cytotoxic T cells eventually resulting in AIDS
Why are antibiotics not effective against HIV
antibiotics stop cell wall synthesis, and block ribosomes and translation
Viruses don’t have a cell wall, and they do not have any ribosomes or process of translation
why does HIV only infect T helper cells
the attachment proteins on HIV only bind to the receptor proteins on the surface of the T helper cell
What is the long form of AIDS
acquired immunodeficiency syndrome
