HIV and AIDS Flashcards
What cells are suitable as hosts to a virus?
CD4 and T lymphocytes
What is required in order for the HIV virus to enter the cell?
certain receptors
What do the receptors interact with?
protein complexes embedded in the viral envelope
What are protein complexes composed of?
2 glycoproteins
- extracellular GP120 - transmembrane GP41
What are the 3 essential replication enzymes?
- integrase
- protease
- reverse transcriptase
What does reverse transcriptase do?
it begins the reverse transcription of viral RNA
What are the 2 catalytic domains of reverse transcriptase?
- the polymerase active site
- the ribonuclease H active site
What happens at the polymerase active site?
single stranded RNA is transcribed into an RNA-DNA double helix
What happens at the ribonuclease H active site?
The RNA is broken down
What happens to the DNA strand?
It is fused with another DNA strand via the polymerase active site to form a DNA double helix
What does integrase do?
It cleaves a dinucleotide from each 3’ end of the DNA creating 2 sticky ends. After this it transfers it into the cell nucleus and facilitates its integration into the host cell genome
What does the viral protease do?
Cleaves longer viral proteins into smaller core proteins which creates an infectious virus
Once the core proteins are formed what happens?
2 viral RNA strands and the replication enzymes come together and the core proteins assemble around them forming the capsid
What percentage of world population does not have HIV virus receptors?
1%
What viral characteristic ensures HIV cannot be treated?
the glycoproteins constantly change position
What cells do not allow infection of the virus?
Killer cells (KC) and natural killer cells (NKC)
HIV is a ____virus
retro
What does is a retrovirus?
It is an RNA virus that must reverse to the DNA before reproducing/replicating
What are the 2 types of HIV?
HIV-1 and HIV-2
Describe HIV-1
It is highly virulent, highly infective, and global
Describe HIV-2
It isn’t as virulent, not very infective, and only found in West Africa
What is the major difference between HIV and AIDS?
HIV is treatable, while AIDS is not
What is the diagnosis between HIV and AIDS based off of?
the number of lymphocytes
- If patient has 200-250 they have AIDS - If they have more than 250 they still have HIV
How many stages of HIV/AIDS are there?
4
