3.2.4.7 - HIV Flashcards
What does HIV stand for?
Human immunodeficiency virus
What does AIDS stand for?
Acquired Immune Deficiency Syndrome
Is it possible to catch AIDS? Why?
No. AIDS results from HIV which is contagious
When was AIDS first diagnosed?
1981
What surrounds the HIV virus?
lipid envelope
What structures are embedded within the lipid envelope surrounding the viral cell?
attachment proteins
What layer is inside of the lipid envelope on an HIV virus?
capsid
What is inside of the capsid on an HIV virus?
RNA and some enzymes
What is the enzyme found within the capsid of the HIV virus?
Reverse transcriptase to make DNA from RNA using the host cells organelles.
The presence of the enzyme reverse transcriptase means that HIV belongs to which group of viruses?
retroviruses
How does HIV get its genetic information into its host cell?
- HIV enters the bloodstream and circulates
- A protein on the HIV binds to CD4 (a protein) found on helper T cells
- the HIV capsid fuses with the hose cell membrane
- the RNA and enzymes move from the HIV virus into the helper T cell
- the HIV reverse transcriptase converts the RNA into DNA.
How does HIV replicate in its host cell?
- the HIV reverse transcriptase converts the RNA into DNA.
- the new DNA moves into the hose cells nucleus and incorporates into the genetic material.
- protein synthesis occurs and the DNA is used to create mRNA.
- the mRNA passes out of the nuclear pore and undergoes protein synthesis to make new viral proteins.
- the new HIV viral cells break away from the helper T cells with a piece of the membrane around them to form their lipid envelope.
What happens to the immune system with no helper T cells?
helper T cells are important in cell mediated immunity. Without them B cells and cytotoxic T cells are not stimulated to kill pathogens. This means the body is unable to create an immune response to infection.
What are the common secondary infections suffered by HIV patients which often result in death?
infections of the lungs, intestines, brain and eyes, as well as weight loss and diarrhoea.
does HIV kill individuals directly?
No. The secondary infections cannot be fought off by the weakened immune system.