Immunity Flashcards
What are the ten stages of the HIV life cyle?
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- Free virus
- Attachment & entry
- Penetration
- Reverse transcription
- Integration
- Transcription
- Assemby
- Budding
- Freedom
- Maturation
What is first step of the HIV cycle?
Free virus
What is the second phase of the HIV cycle?
Attachment and Entry
- Virus binds to CD4 molecule (Helper T cell) on its surface
Another name for the Helper T cell?
CD4
What is the third phase in the HIV cycle?
Penetration
- Virus empties into contents into cell
What is the fourth phase in the HIV cycle?
Reverse Transcription
- Converts RNA to DNA
- The reverse transcriptase enzyme makes a “mirror image” of viral RNA strands to create double-stranded DNA
What is the fifth phase of the HIV cycle?
Integration
- Viral DNA is inserted into the cell’s own DNA by the integrase enzyme
- The viruse and your cell are one
What is the sixth phase in the HIV cycle?
Transcription
- When the infected cell divides, the viral DNA is “read” and long chains of proteins are made
- Protein synthesis into making new HIV virus
What is the seventh stage of the HIV cycle?
Buddling
- Immature virus pushes out of the cell
- Takes some cell membrane with it
- The protease enzyme starts processing the proteins in the newly forming virus
What is the ninth stage of the HIV cycle?
Freedom
- Immature virus breaks free of the infected cells
What is the tenth phase in the HIV cycle?
Maturation
- The protease enzyme finished cutting HIV protein chains into individual proteins
- These combine to form the viral core
- Makes a new working virus
What is an antigen?
Antigen
- Marker/ badge on the outside of a cell
How does the immune system recognize antigens?
Helper T Cells
- Also known as CD4s
What are the immuni-dominant antigents of influenza?
Ig H & Ig N
(ex: H1N1)
On what part of the influenza virus are the antigens located?
Antigens N and H are located on the surface of the viruse
What occurs during an “antigenic shift”?
The antigens change (shift) to create a new strain
What is antigenic shift?
Antigenic shift is the process by which two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains
What are the componets of the yearly influenza vaccine?
Antigens H and N
What are the reasons that your friend who had the flu shot but got the flu anyway?
- It was a different strain of the flu that your friend wasn’t immunized for
- Had the flu already (waited too long to get the flu shot)
What other organisms can be affected by influenza?
- Pigs
- Humans
- Birds
How does the influenza virus spread within the organims and determines productive replication of the virus?
Via mutations and antigenic shifting of the influenza virus
What is an epidemic?
Epidemic
a widespread occurrence of an infectious disease in a community at a particular time
What is a cytokine storm?
Cytokine storm
The body overreacts to the virus and it causes it to destroy its down organs
Rambo overreaction
How does the immune response to yearly flue differ from that of the avian flu?
Cytokine storm
The H1N1 influenza has been the cause of four pandemics in recent history: 1918, 1957, 1968, and 2009. How is this possible to have multiple H1N1 pandemics in the same century?
- Antigenic shift of H1N1 virus
- Loss of memory T and B cells in the human body
What possible outcomes might happen if swine flu (H1N1) and avian flu (H5N1) reassorted?
Super flu- a flu that we have not experienced yet