Viral Structure and Function II

Question 1

Eclipse period:

Answer 1

no infectious virus detectable inside or outside the cell (have released their genomes and are no longer infectious = can’t be detected as plaque forming units (PFUs))

Question 2

latent period:

Answer 2

time between initiation of infection to the cell releasing the new infectious virus particles

Question 3

stages of the latent period:

Answer 3

attachment, entry and uncoating, gene expression, genome replication, assembly and egress.

Question 4

Attachment:

Answer 4

specific binding of a virus-attachment protein with a cellular receptor moledule (ex. Of target receptor molecules = proteins and carbs [carbs are less specific])

Question 5

Entry:

Answer 5

soon after attachment. Energy dependent process can involve endocytosis (non-enveloped) or fusion with a cellular membrane (enveloped)

Question 6

Uncoating:

Answer 6

capsid is fully/partially removed and the virus genome is exposed

Question 7

Assembly:

Answer 7

capsid assembles around genome or genome is inserted into preformed capsids

• helical: during synthesis, viral genome is coated with nucelocapsid protein
• can often detect the inclusions on the cytoplasm or nucleus with light microscopy

Question 8

Egress:

Answer 8

exit from the host

• non-enveloped -> lysis
• enveloped -> directly released into extracellular environment (if budded into plasma memb) or secreted (if budded into golgi or ER)