Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Virology > Week 4 > Flashcards

Week 4 Flashcards

1
Q

List the 7 steps of virus replication.

A
  1. Attachment of virion to host cell
  2. Entry into host cell
  3. Transcription of virion genes to mRNA
  4. Translations of virus mRNA into proteins
  5. Genome replication
  6. Assembly of protein genomes into virions
  7. Exit cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is the nucleocapsid assembled in helical viruses?

A
  • copies of one protein species bind to helical ssRNA molecule
  • more copies bind until RNA is coated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is the nucleocapsid assembled in icosahedral viruses?

A
  • protein shell (procapsid) is made
  • copy of virus genome enters procapsid
  • built around scaffolding protein (modifications form capsid)
  • scaffolding is removed as genome is packaged
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How are virus genomes selected from all the cell and virus nucleic acids?

A
  • specific sequence of viral genome is recognized by viral proteins (packaging signals)
  • intermediate molecules are NOT packaged and left outside
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Simple viruses like TMV assemble (______), while complex viruses like herpes virus assemble (_____).

A. by themselves; need the environment of host cells
B. need the environment of host cells; by themselves

A

A. by themselves; need the environment of host cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

T/F. If the membrane of a virus is outside of the capsid, the virus must have gained the membrane by budding through cell membranes.

A

False. HSV gains envelope in the cytosol, not by budding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

De novo synthesis is…

A

when membrane is synthesized late in the replication cycle or membrane forms a layer below the surface of the capsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 3 ways virion membranes are formed?

A
  1. budding
  2. budding with exocytosis
  3. de novo synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do interactions between proteins of enveloped viruses differ?

A
  • intermediates
  • surface protein binds to matrix protein and THEN binds to nucleocapsid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the steps of cell lysis in bacterial cells.

A
  1. phages produce enzymes (lysozymes)
  2. bonds of peptidoglycan break cell wall
  3. lysis
    or
  4. phages synthesize proteins that inhibit host enzymes
  5. cell walls not reinforced and weaken
  6. lysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

T/F. The more resources virions require, the fewer virions produced per cell.

A

True. Large phages use more resources.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 4 types of cell infection?

A

(nonproductive)
1. Abortive infection: neither productive or latent due to mutations
- can infect another cell that has missing component to replicate genome

  1. Latent infection : virus genome stays with cells for lifetime

(productive)
3. Productive infection: release of progeny virions from infected cell
4. Programmed cell death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What proteins are synthesized in innate immunity to protect adjacent cells from infection and activate T-cells?

A

Interferons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a trigger for interferon production?
A. dsRNA
B. ssDNA
C. ssRNA
D. dsDNA
E. Both A and C

A

E. Both A and C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

If a cell becomes infected, what are interferons successful in doing?

A

Block virus replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Name the two anti-viral interferons.

A

Interferon α and β

17
Q

What are the 4 antiviral activities triggered by Interferon α and β.

A
  1. activation of genes that encode for viral proteins
  2. Stimulation of MHC I (Tcytotoxic cells) to enhance presentation of peptides on T-cell surface
  3. Activation of NK cells
  4. Apoptosis
18
Q

What is the function of NK lymphocytes?

A
  1. recognize changes in surface molecules on virus-infected cells and kill them
  2. release γ interferons to activate macrophages
19
Q

What are the cells associated with adaptive immunity?

A

B-cells (antibodies)
T-cells (Th and Tc)

20
Q

Antibodies help…..

A
  • neutralize infectivity
  • enhance phagocytosis
  • activate complement proteins (detergent: break up viral envelope)
21
Q

What is RNA silencing?

A
  1. viral RNA triggers protein production
  2. protein degrades mRNA
  3. backfires on virus
22
Q

How are viruses of human and other invertebrates commonly named?

A
  • disease they cause
  • where the disease was first reported
23
Q

How are insect viruses named?

A
  • name of insect
  • effect of infection on host
24
Q

How are plant viruses named?

A
  • the host
  • sign of disease
25
Q

If a virion has a layer of membrane outside of its capsid, the membrane is most likely gained from:
- plasma membrane
- de nova synthesis
- inherited from plant viruses
- ER

A
  • plasma membrane
  • ER
26
Q

Which of the following is NOT a mechanism by which antibody fight virus infection?
A. Bind to viruses and allow certain type of immune cells to phagocytose viruses or kill them.
B. Bind to viruses and degrade the virions.
C. Activate complement proteins and therefore inactivate viruses.
D. Neutralize virus infectivity.

A

B. Bind to viruses and degrade the virions.

27
Q

How do memory cells help to fight viral infection?
A. Remember the virus, if the same virus infects again, the cells and quickly phagocytose them.
B. Remember the virus, if the same virus infects again, the cells can alarm the immune system to respond to the infection.
C. Remember the virus, if the same virus infects again, they can respond quickly by making specific antibodies and T cells to fight the infection.
D. Remember the virus, if the same virus infects again, they can quickly neutralize the virus.

A

C. Remember the virus, if the same virus infects again, they can respond quickly by making specific antibodies and T cells to fight the infection.

28
Q

The only way to establish a latent infection is to integrate viral genome into host cell genome.

A

False.
- genome integration
- extra chromosome

29
Q

Receiving COVID-19 vaccine will enable your body to _______ when you are infected with SARS-CoV-2. Select all that apply.
- produce specific antibody quicker
- produce more specific antibody
- produce more T cells against the virus
- produce more types of antibody for the body to choose from

A
  • produce specific antibody quicker
  • produce more specific antibody
  • produce more T cells against the virus

Virology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions