4.1.1: Communicable Diseases: Viruses Flashcards
What are viruses?
Non-living and acellular entities smaller than bacteria that contain genetic material, a capsid, and attachment proteins.
Where does viral replication occur?
Inside host cells, involving the injection of nucleic acid into the cell.
What is a bacteriophage?
A type of virus that infects bacteria.
What are the structural features of HIV?
- Reverse transcriptase
- Protein attachments
- Capsid
- Core
- Envelope
What is the function of reverse transcriptase in HIV?
It copies the viral RNA into a DNA copy.
What does the envelope of HIV consist of?
An extra outer layer made of lipids taken from the host’s cell membrane.
What is the role of CD4 protein in HIV infection?
HIV attaches to the CD4 protein on helper T cells.
What happens when HIV enters a helper T cell?
The HIV protein capsule fuses with the helper T cell membrane, allowing RNA and enzymes to enter.
What is meant by ‘HIV positive’?
A person who is infected with HIV.
What is AIDS?
A condition where replicating viruses in helper T cells interfere with normal immune function.
What is the primary consequence of HIV destroying helper T cells?
The host becomes unable to produce an adequate immune response to other pathogens.
What is the primary cause of death in HIV/AIDS patients?
Destruction of the immune system rather than HIV directly.
What family do influenza viruses belong to?
Orthomyxoviridae.
What cells do influenza viruses infect?
Ciliated cells lining gas exchange surfaces.
What can cause the most harm during an influenza infection?
Secondary infections resulting from the initial infection.
What is a common secondary infection associated with influenza?
Pneumonia caused by bacteria that infect the airways.
Who is at higher risk of severe symptoms from influenza?
- Young children
- The elderly
- Individuals with a lowered immune system
Fill in the blank: Symptoms of influenza include _______.
Headache, Fever, Runny or stuffy nose, Sore throat, Aches, Coughing, Vomiting.
