Lecture 2 Flashcards
What are the steps in viral replication (6)
- Attachment
- Penetration
- Uncoating
- Replication of viral proteins and nucleic acid - eclipse phase
- Assembly of the viral proteins and packaging of the nucleic acids
- Release of virions
What is attachment
Ligands/receptors sites on the surface on the surface of the visions bind to receptors on the cell surface
How is the initial binding of attachment done
Electrostatic forces
How does attachment occur
when there is a specific affinity exists between the cell and the virus
What determines TROPISM of viruses
Presence or absence of sites
How does a reversible bond work
A loose contact between cell membrane and virus which depend upon the maintenance of the electrostatic forces produced by the concentration of electrolytes
What is the reversible bond dependent on
Temperature
How does the irreversible bond work
Late stage of the process which become temperature dependent. The virus is now protected from antibodies
What are the 2 mechanisms of penetration
- Endocytosis
2. Fusion
How is the process of uncoating brought about
Lysosomes
How does the Eclipse phase occur
- DNA is transcribed to viral mRNA which is translated to viral proteins
- The gnome of positive strand RNA viruses may function as a mRNA
What type of proteins make up a virion
Structural protein
What functions do non-structural proteins have
Protease and transcriptase activity or transport of other proteins
Where is viral DNA transcribed
Nucleus
How are helical capsids assembled
Helical capsids usually assemble around strands of nucleic acids
