TOPIC 2 HIV and aids Flashcards
What does HIV affect?
-The immune system
What does HIV lead to?
-AIDS
What are the consequences of aids?
-Immune system deteriorates and eventually fails
What are the host cells for HIV?
Helper T cells
What does HIV do to the T cells?
-Infects and eventually kills them
Why do people infected with HIV develop AIDS?
-Helper T cells are at a critically low level
Why are people with HIV immunocompromised?
-Without enough helper T cells the immune system cannot mount an effective response to infections as other immune system cells don’t behave as they should
What happens during the initial infection period?
-HIV replicates rapidly
-The infected person may experience severe flu-like symptoms (as the immune system mounts a response)
What is the latency period?
-When HIV replication drops to a lower level
-The person doesn’t experience any symptoms
How long do AIDs take to develop typically develop?
usually around 10 years
What are the initial symptoms of aids?
-Minor infections of mucous membranes (the inside of the nose, ears and genitals)
-Recurring respiratory infections
What happens as aid progresses?
-The number of immune system cells decreases
-More susceptible to serious infections such as chronic diarrhoea, severe bacterial infections and TB
What factors affect how long AIDS sufferers survive?
-Existing infections
-Strain of HIV they are infected with
-Age
-Access to healthcare
What is the structure of HIV?
-Spherical
-Core contains genetic material (RNA transcriptase)
-Proteins- including the enzyme reverse transcriptase used for virus replication
-Capsid and envelope (made from stolen membrane of the host cell)
-Attachemnt protein- allows HIV to attach to host helper T cell
Why do viruses (specifically HIV)) replicate inside host cells?
-They do not have the enzymes and ribosomes to replicate on their own
What is step 1 of HIV replication?
The attachment protein attaches to a receptor molecules on the T cell membrane
What is step 2 of HIV replication?
The capsid is released into the cell, it uncoates and realease the genetic material (RNA) into the cytoplasm\\
What is step 3 of HIV replication?
Reverse transcriptase is used to make a complementary strand of DNA from a viral RNA template
What is step 4 of HIV replication?
From this double-stranded DNA is made and inserted into the human DNA
What is step 5 of HIV replication?
Host cell enzymes are used to make viral proteins from the viral DNA found within the human DNA
What is step 6 of HIV replication?
Viral proteins are assembled into new viruses, which bud from the cell and go and infect other cells
How do antibiotics kill bacteria?
-By interfering with their metabolic reactions (target bacterial enzymes and ribosomes)
Why do antibiotics only target bacterial enzymes?
So they don’t damage human ones
Do antibiotics kill viruses?
No
What are antiviral drugs used for?
To target the very few virus-specific enzymes
What are the best ways of reducing HIV infection rates?
-Reducing the spread- protected sex, not sharing bodily fluids and not passing HIV onto children
What are used to slow down the progression of HIV?
-Antiviral drugs
What reduces the chance of the baby being HIV positive?
-The mother taking HIV drugs during pregnancy
