2C HIV & Viruses Flashcards
How does HIV affect the immune system?
It infects helper T cells which act as the host for HIV
Without the T cells, chemicals aren’t released to activate phagocytosis, cytotoxic cells or B cells so an effective response to the disease can’t be performed
Describe the structure of the HIV virus
> CORE containing RNA and REVERSE TRANSCRIPTASE (needed for replication of viruses)
outer coating of PROTEIN = CAPSID
additional outer layer = ENVELOPE - made from the CELL MEMBRANE of the HOST cell
has lots of ATTACHMENT PROTEIN copies on the envelope that allow HIV to attach to the HOST T- HELPER CELL
Describe the process by which HIV replicates
> attachment protein joins to a receptor molecule on the T helper cell membrane
capsid is released into the cell where it uproots and releases genetic material into the cell’s cytoplasm
reverse transcriptase is used to make a complementary strand of DNA from the viral RNA template
double-stranded DNA is made from this and released into human DNA
cell enzymes are used to make viral proteins from the viral DNA in the human DNA
the viral proteins are then assembled into new viruses which then go and infect other cells
Why don’t antibiotics work on viruses?
> viruses don’t produce their own enzymes and ribosomes so use the host’s
antibiotics don’t target human processes as it would damage human cells
What can be used to slow the progression of HIV? Describe them and give an example
Antiviral drugs
They target a few viral-specific enzymes
Reverse-transcriptase inhibitors
