Intro to virology Columbo TEST #1 1/9/17

Question 1

What are viruses typically composed of?

Answer 1

• Nucleic acid (genetic material)

- Protein sheath

Question 2

What is the entire viral construction outside of a cell referred to as?

Answer 2

-Virion

Question 3

T/F

Viruses have organelles so they can replicate on their own

Answer 3

False

-They have no organelles, nor can they replicate on their own

Question 4

Viruses are what type of parasite?

Answer 4

-Obligate intracellular parasites

Question 5

What is the capsid?

Answer 5

-The outer protein sheath of a virus

Question 6

What are the three shapes of capsids?

Answer 6

• Helical
• Icosahedral
• Complex

Question 7

What type of capsid is roughly spherical?

Answer 7

-Icosahedral

Question 8

What type of capsid is cylindrical?

Answer 8

-Helical

Question 9

What are the three basic functions of the capsid?

Answer 9

• Protect the genetic material of the virus
• Aid entry into the cell in terms of attachment and or penetration of the cellular membrane
• Package viral enzymes used in viral replication

Question 10

T/F

The protein sheath (capsid) helps control the specificity of a virus

Answer 10

True

Question 11

T/F

The capsid is composed of a collection of individual repeating subunits

Answer 11

True

Question 12

Tobacco Mosaic Virus is what type of virus?

• Helical
• Icosahedral
• Complex

Answer 12

Helical

Question 13

What are the repeating subunits found on an icosahedral virus?

Answer 13

-Capsomeres

Question 14

What are 5-6 individual protein structure called in an icosahedral virus?

Answer 14

-Protomer

Question 15

If a virus pinches part of the host cells lipid membrane what are they said to be?

Answer 15

-Enveloped virus

Question 16

Spikes or envelope proteins are made of what?

Answer 16

-Viral glycoproteins

Question 17

If you have viral glycoproteins embedded in the enveloped virus what are they called?

Answer 17

-Spikes or envelope proteins

Question 18

Enveloped virus typically have a layer of proteins between the capsid and envelope called what?

Answer 18

-Tegument or matrix protein

Question 19

What helps hold the whole envelope virus together?

Answer 19

-Tegument or matrix protein

Question 20

What type of genetic material do viruses contain?

Answer 20

-Either DNA or RNA

Question 21

What does positive sense in terms of an RNA virus indicate?

Answer 21

-It can be directly translated into viral proteins (5’ to 3’) (effectively mRNA)

Question 22

What does negative-sense indicate?

Answer 22

-Need to form a complementary strand which then can be translated into viral proteins (3’ to 5’)

Question 23

What does negative sense viruses often carry within the virion?

Answer 23

-RNA dependent polymerase

Question 24

Define ambisense?

Answer 24

-Contains both positive and negative sense RNA on same strand

Question 25

What does sense refer to in viruses?

Answer 25

-The reading (translation) direction of the genetic material

Question 26

T/F | Viruses use locomotion to reach cells.

Answer 26

False | -They depend on collision

Question 27

Where do viruses attach on the naked virus?

Answer 27

-Capsid

Question 28

T/F | Viruses can also require a co-receptor to enter a cell

Answer 28

True

Question 29

What is the eclipse phase?

Answer 29

-The virus is inside the host cell and becomes off the immune system radar.

Question 30

What is the process referred to that viruses use to get genetic material into the cell?

Answer 30

-Uncoating

Question 31

What are the two pathways that enveloped viruses use to enter the cell?

Answer 31

- Direct fusion | - Viropexis

Question 32

What type of entry does the enveloped virus such as, HIV-1, herpesviruses, or paramyxoviruses use?

Answer 32

-Direct fusion

Question 33

What type of entry does influenza, rubella, and rabies viruses use to enter a cell?

Answer 33

-Viropexis

Question 34

How do naked viruses typically enter a cell?

Answer 34

-Viropexis

Question 35

In order for viruses to transcribe what must it ultimately become?

Answer 35

-Sense mRNA (positive RNA)

Question 36

When the viral DNA folds in a way that allows replication to produce a series of repeated viral genomes is termed what?

Answer 36

-Concatemer

Question 37

T/F | The location of viral replication determines the enzymes the virus needs to bring with them

Answer 37

True

Question 38

What are the two phases of herpesvirus?

Answer 38

- Latent phase | - Lytic phase

Question 39

What is the active replication phase of herpesvirus called?

Answer 39

-Lytic phase

Question 40

What is the phase of herpesvirus when it is dormant in a circular configuration within the nucleus?

Answer 40

-Latent phase

Question 41

RNA + (sense) viruses have genetic material that allows what?

Answer 41

-Directly read by host ribosomes

Question 42

What do RNA + (sense) viruses need to replicate their genetic material?

Answer 42

-Make complementary RNA - (antisense)

Question 43

What do RNA - viruses need to make?

Answer 43

-Complementary RNA + that can be read by host ribosomes

Question 44

What does RNA - need to pack to make RNA +?

Answer 44

-RNA reverse polymerase

Question 45

Where can RNA - viruses replicate?

Answer 45

- Cytoplasm | - Nucleus

Question 46

What are retroviruses?

Answer 46

-RNA that reproduce via a DNA intermediate

Question 47

What allows the formation of DNA from RNA?

Answer 47

-Reverse transcriptase enzyme

Question 48

What integrates the viral DNA into the host genome?

Answer 48

-Viral integrase

Question 49

When the virus is being replicated along with everything else in the cell cycle what is the stage of the virus called?

Answer 49

-Provirus

Question 50

What is the term used to describes the insertion of individual viral genomes into individual capsids?

Answer 50

-Encapsidation

Question 51

What is the specific site on the viral genome that codes for proteins intended to initiate assembly called?

Answer 51

-Packaging site

Question 52

How do naked viruses typically exit the cell?

Answer 52

-Lysis or apoptosis

Question 53

How do enveloped viruses typically exit the cell?

Answer 53

- Exocytosis | - Budding from plasma membrane

Question 54

When you have DNA viruses what generates mRNA?

Answer 54

-RNA polymerase II of herpes alpha components

Question 55

What are herpes alpha proteins are transcription factors for?

Answer 55

-Beta components

Question 56

What is the concatemer cleaved into prior to assembly?

Answer 56

-single strand viral genomic DNA

Question 57

What is a group 1 virus?

Answer 57

-Double stranded DNA +/-

Question 58

What is a group 2 virus?

Answer 58

-Single stranded DNA positive sense

Question 59

What is a group 3 virus?

Answer 59

-Double stranded RNA

Question 60

What is a group 4 virus?

Answer 60

-Single stranded RNA positive sense

Question 61

What is a group 5 virus?

Answer 61

-Single stranded RNA negative sense

Question 62

What is a group 6 virus?

Answer 62

-Single stranded RNA positive sense with reverse transcriptase

Question 63

What is a group 7 virus?

Answer 63

-Double stranded DNA turned into RNA then reverse transcribed back into DNA

Question 64

In direct fusion what happens with the viral envelope?

Answer 64

-Stays at the plasma membrane

Question 65

In direct fusion what happens to the capsid and genetic material?

Answer 65

-Enter the cytoplasm

Question 66

What is viropexis similar to?

Answer 66

-Receptor mediated endocytosis

Question 67

In Viropexis what happens with the virus?

Answer 67

-Binds the receptors on the cell surface ultimately internalizing and dragging the viral capsid along

Question 68

When the virus is brought the cell via viropexis how does the genetic material get released?

Answer 68

-The low pH endosomal vesicle causes fusion and release of the nucleocapsid (genetic material) into the cytoplasm