Viruses Flashcards
Do viruses share characteristics with cells?
No
What is the virion and what does it contain?
Infectious viral particle
Nucleic acid surrounded by protein coat
Capsid
What is the protein coat for?
A protection and transmisttion
What is nucleic acid?
DNA or RNA never both
What is the capsule made of?
Capsomere submits
One or several types of proteins
What does the envelope contain?
Lipids
Proteins
Carbohydrates
What is the envelope?
A lipis bilayer that surrounds the viral capsid
Are all viruses enveloped?
No
How are viral genomes classified?
Nucleic type
Strategy for replication
Morphology
Can viral gemones be RNA or DNA?
Both
Do Viral genomes have to be singles stranded or double stranded?
Both
What are the different types of viruses?
HIV
Hepatitis B
Ebola virus
Advenovirus
Influenza
Bacteriophage
What is the basis of host range?
The ability to hind to the host cell
What is the attachment called whith the interaction between ligands on the virus surface and the receptors on the cell surface?
Lock and key
What is the lytic viral infection cycle?
Attachment
penetartion
Uncoating
Replication
Assembly
Viron release
What is it meant by attachment in the lytic viral infection cycle?
Proteins on the capsid or envelope interact specifically with receptors on the host cell surface
What is it meant by penetration in the lytic viral infection cycle?
Attachment induces conformational changes in the virus resulting in fusion of membranes
Some viruses can also enter ny endocytosis
What is it meant by uncoating in the lytic viral infection cycle?
Viral capsid is removed and degraded by viral or host enzymes
Viral DNA is released
What is it meant by replication in the lytic viral infection cycle?
Transcription and translation of the viral genome is initiated
New viral genomes and viral proteins are made
What is it meant by assembly in the lytic viral infection cycle?
Viral proteins are packaged with the newly synthesised ciral genome into virons ready to be released from the host cell
What is it meant by viron release in the lytic viral infection cycle?
LYSIS or BUDDING
Lysis results in death of the cell and the viruses are cytolytic
Budding results in the acquisition of a viral envelope, do not kill the cell and are known as cytopathic
What are the differences between lytic and lysogenic cycles of bacteriophage?
Lysic results in lysis of the host cell and lysogenic do not lyse
In lytic the viral DNA is not intergrated into the host genome whereas in lysogenic the viral DNA is integrated into the host genome and the prophage stage is when viral genome is part of the host genome
Lytic, the viral DNA replication is seperate from host DNA replication and in lysogenic the viral DNA is replicated along with normal host DNA replication
Lytic progeny virus is released during lysis or budding and in lysogenic the progeny virus is not released until switched back to lytic cycle
Example of lysic is influenza that effects the lungs
Example of lysogenic is herpes virus that can be undetected for a long period of time
