HIV Flashcards
(34 cards)
What does HIV stand for?
Human immunodeficiency virus.
What causes AIDS?
HIV
What does AIDS stand for?
Acquired Immune Deficiency Syndrome
What is the structure of HIV?
The lipid envelope contains attachment proteins. Inside the envelope is a protein layer which is the capsid. The capside encloses two single strands of RNA and some enzymes.
What is the name of one of the enzymes in HIV?
Reverse transcriptase.
Why is the enzyme called reverse transcriptase?
This is because it catalysés the production of DNA from RNA.
What group of viruses does HIV belong to?
Retroviruses
Why is HIV a retrovirus?
Because of the reverse transcriptase enzyme.
What happens following infection?
HIV enters the bloodstream and circulates around the body.
What type of cell does HIV most frequently attach to?
T helper cells.
How do the RNA and enzymes of HIV enter the helper T cell?
The capside fuses with the cell-surface membrane.
What protein does HIV readily bind to?
CD4
What converts the virus’s RNA to DNA?
The HIV reverse transcriptase.
Whee is the newly made HIV moves to ?
It is moved I to the nucleus of the T helper cell where it is inserted into the cells DNA.
What creates mRNA?
The HIV DNA in the nucleus creates mRNA Udin the cell’s enzymes.
What instructions does the mRNA contain?
The instructions to make new viral proteins and the RNA to go into the new HIV.
How does the mRNA pass out of the nucleus?
It leaves via a nuclear pore.
What does the mRNA use to make HIV particles?
The cell’s protein synthesis mechanisms.
What happens when the HIV particles break away from the helper T cells?
They take a piece of the cell-surface membrane with them to form their lipid envelope.
What does the replication often go into?
It goes into dormancy and only recommences, leading to AIDS, many years later.
How does HIV cause AIDS?
By killing or interfering with the normal functioning of T helper cells.
What can happen without a sufficient number of T helper cells?
The immune system cannot stimulate B cells to produce antibodies or cytotoxic T cells.
What other cells may also become infected or destroyed?
Memory cells.
What happens as a result of the weak immune system?
The individual becomes more susceptible to cancers and infections.
