TOPIC 2 HIV and aids Flashcards
(28 cards)
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
