Virus Life Cycle

Question 1

What structures interact in virus recognition?

Answer 1

ECM (tissues) and virion

Question 2

What structures interact in virus attachment?

Answer 2

virion and specific cellular receptor

Question 3

What is the viral host range?

Answer 3

preferred species

Question 4

What is the viral tissue tropism?

Answer 4

preferred cell type

Question 5

What makes a cell susceptible to viral infection?

Answer 5

virus can enter

Question 6

What makes a cell permissive to viral infection?

Answer 6

virus can replicate and synthesize

Question 7

What happens in a viral abortive infection?

Answer 7

viral replication is incomplete

Question 8

what are the three mechanisms of viral penetration?

Answer 8

receptor-mediated endocytosis
pinicytosis
phagocytosis

Question 9

what are the two ways a virus can enter a cell?

Answer 9

penetration

fusion

Question 10

What happens in viral fusion?

Answer 10

virion envelope fuses with plasma membrane, leaves parts of virion behind

Question 11

what is released in viral uncoating? what does this mark the beginning of?

Answer 11

genome is released

beginning of eclipse phase

Question 12

Besides direct penetration, what are three mechanisms/locations of viral entry and uncoating?

Answer 12

at plasma membrane
endocytosis
at nuclear pore

Question 13

Do viruses made mRNA?

Answer 13

yes - all do

Question 14

Are the transcriptions factors which regulate mRNA synthesis viral or host?

Answer 14

Both

Question 15

Where does the machinery to translate mRNA into protein come from? What molecules are used?

Answer 15

Host

ribosome, tRNA, amino acids

Question 16

During virion assembly, what viral proteins interact with the newly made genomes?

Answer 16

capsid proteins

Question 17

During virion assembly, what do membrane proteins traffic through?

Answer 17

secretory pathway

Question 18

During virion assembly, what do cystolic proteins accumulate next to?

Answer 18

membrane

Question 19

What marks the end of a viral eclipse phase?

Answer 19

virion assembly

Question 20

When are the steps of virion assembly?

Answer 20

capsid proteins form empty shell

viral DNA inserted into capsids

Question 21

which shapes of capsids self-assemble?

Answer 21

icosahedral

helical

Question 22

what kind of capsid is made of a genome coated with nucleoproteins?

Answer 22

complex capsid

Question 23

From where do enveloped viruses acquire membranes?

Answer 23

host ER, golgi, or PM

Question 24

What must happen before capsid assembly? Can this happen at the same time as envelopment?

Answer 24

all virion components assemble at site of capsid assembly

cannot happen at the same time as envelopment

Question 25

How are virions released from the cell?

Answer 25

lysis budding exocytosis

Question 26

which form of virion release is active transport?

Answer 26

exocytosis

Question 27

How is the eclipse phase of a single-step virus growth curve characterized?

Answer 27

no virus it recovered - replication and assembly

Question 28

What is a viral burst size?

Answer 28

number of infectious viral progeny from a single round of replication

Question 29

What is a PFU? What does it measure?

Answer 29

Plaque Forming Unit | measures infectious virions