Intro

Question 1

What is a Virion?

Answer 1

A viral particle

Question 2

True or False:

A virus can’t have DNA

Answer 2

False: Viruses exist as both DNA and RNA.

Question 3

What four types of genome can a virus have?

Answer 3

Double Strand (ds) DNA, Single Strand (ss) DNA, ds RNA, or ss RNA.

Question 4

A ____ is a structural protein polymer, symmetrical and rigid Surrounding the Nucleic acid of a virus

Answer 4

Capsid

Question 5

____ a membrane containing viral glycoproteins..

Answer 5

Envelope

Question 6

Is an Enveloped Virus stronger than a virus without one?

Answer 6

No. Their envelope is essential for their integrity, but it is fragile, it can be destroyed by excessive temperature or pH, dryness, or detergents

Question 7

True or False:

Enveloped Viruses can more easily fuse with cell walls.

Answer 7

True

Question 8

These are examples of what?
Structure: size, morphology, and nucleic acid (e.g., picornavirus [small RNA]

Biochemical characteristics: structure and mode of replication

Disease they cause

Means of transmission

Host cell (host range): animal (human, mouse, bird), plant, bacteria

Tissue or organ (tropism)

Answer 8

Virus classifications/names

Question 9

In Baltimore classification a Class I virus is?

Answer 9

dsDNA

Question 10

In Baltimore classification a Class II virus is?

Answer 10

ssDNA

Question 11

In Baltimore classification a Class III virus is?

Answer 11

dsRNA

Question 12

In Baltimore classification a Class IV virus is?

Answer 12

ssRNA positive

Question 13

In Baltimore classification a Class V virus is?

Answer 13

ssRNA negative

Question 14

In Baltimore classification a Class VI virus is?

Answer 14

Retrovirus: single stranded positive RNA virus that replicates via DNA synthesis

Question 15

In Baltimore classification a Class VII virus is?

Answer 15

dsDNA virus replication through ssRNA intermediate (HBV)

Question 16

A virus that replicates backwards is called?

Answer 16

Retrovirus

Question 17

What 2 ways might cell penetration take place?

Answer 17

Surface fusion or Endocytosis, followed by endocytic fusion

Question 18

Once inside the cell what process must occur?

Answer 18

Uncoating

Question 19

Where do most DNA viruses replicate?

Answer 19

the nucleus

Question 20

Where do most RNA viruses replicate?

Answer 20

Cytoplasm

Question 21

True or False:

All Viruses carry their own enzymes.

Answer 21

False: Most viruses use the cell machinery. Usually only large viruses carry their own enzymes.

Question 22

What are the phases of virus synthesis?

Answer 22

Early and late, although some viruses have a middle phase as well

Question 23

In the ____ phase proteins are synthesized before genome replication: these are the non-structural proteins

Answer 23

Early

Question 24

In the ____ phase proteins are synthesized after genome replication: these are the structural proteins

Answer 24

Late

Question 25

____ the immediate-early proteins. They are involved in transcriptional regulation and are not found in the mature virion. They are also involved in the control of beta protein synthesis

Answer 25

Alpha Proteins

Question 26

____ the early proteins involved also in DNA replication (they include the DNA polymerase and transcription factors). Only a few copies of DNA polymerase need to be made for replication to occur

Answer 26

Beta proteins

Question 27

____ the late proteins and structural components of the virus. The synthesis of gamma proteins is initiated after the start of DNA synthesis

Answer 27

Gamma Proteins

Question 28

True or False: RNA is long lived and can be transcribed by RNA polymerase without error.

Answer 28

False RNA is degraded relatively quickly, the RNAdependent RNA polymerase must be provided or synthesized soon after uncoating to generate more viral RNA, Most viral RNA polymerases work at a fast pace but are also error prone, causing mutations.

Question 29

True or False: ss(-) RNA are complementary to mRNA and thus must be converted to positive-sense RNA.in order to replicate

Answer 29

True

Question 30

True or False: ss(+) RNA can start translation right away once inside a cell. whereas ss(-) RNA must first transcribe then translate.

Answer 30

True

Question 31

(Class III) dsRNA viruses replicate similar to which other RNA virus type? (ClassV) ss(-) or (ClassIV) ss(+)

Answer 31

(Class V) ss(-) in that they need transcription first.

Question 32

What is a provirus?

Answer 32

A DNA virus that has integrated into the host DNA and remains latent for a time

Question 33

These characterize what kind of virus replication? •nucleotide replication occurs in the nucleus using a virus-coded enzyme * (+) strand RNA’s are synthesized and serve as templates for (-) strand genomic RNA’s. * mRNA’s are synthesized from each segment. Some segments give rise to primary transcripts which can be alternatively spliced

Answer 33

segmented RNA replication

Question 34

True of False: Each segment codes for only one protein.

Answer 34

False: A single segment can code for more than one protein since the virus has access to splicing machinery. The mRNAs are transcribed in the nucleus

Question 35

How do (Class VI) retroviruses Replicate?

Answer 35

(Class VI) retroviruses replicate through a DNA intermediate by copying their RNA into DNA by reverse transcription, a process requiring the enzyme reverse transcriptase carried in the virions

Question 36

True of False: This is the order of (Class VI) retro virus transcription; ssRNA → ssDNA → dsDNA → mRNA

Answer 36

True

Question 37

True or False: Infection by viruses is always intracellular.

Answer 37

True

Question 38

____ ____ occurs when two viruses co-infect the same cell and share parts of their genome during replication

Answer 38

Genetic recombination

Question 39

What is Horizontal transmission?

Answer 39

Infection by a person to another person by direct contact or a vector

Question 40

What is vertical transmission?

Answer 40

Passed though lineage like a mother to child through plancenta

Question 41

What is meant by saying viremia?

Answer 41

The virus can relocate using the blood

Question 42

What is cytopathogenesis and what does it tell a person?

Answer 42

Interaction between cells of the target organ and the virus and it determines the outcome of the viral infection

Question 43

What is the outcome of the lytic cycle of a virus?

Answer 43

Release of the virions due to cell lysis.

Question 44

What is the outcome of the lysogenic cycle of a virus?

Answer 44

Integration into the host DNA and gets copied every time the cell replicates.

Question 45

What is an Oncogenic infection?

Answer 45

Induces uncontrolled replication of infected cells (a.k.a. Cancer)

Question 46

What is a Non permissive cell and how does it effect the infection?

Answer 46

a cell that does not permit the virus in any way and causes no infection or an abortive infection.

Question 47

Cells that support viral replication are called?

Answer 47

Permissive

Question 48

What is the virus doing in the eclipse period?

Answer 48

Uncoating and replicating

Question 49

What happens after the latent period of a virus?

Answer 49

Virions release

Question 50

True or False: The latent period , during which extracellular infectious virus is not detected, includes the eclipse period.

Answer 50

True

Question 51

High levels of IgM signal what about an infection?

Answer 51

Current Infection

Question 52

High levels of IgG signal what about an infection?

Answer 52

Past or advanced infection

Question 53

What is a syncytia?

Answer 53

Formation of giant multinucleated cells

Question 54

What is a Prodrome?

Answer 54

An early symptom indicating the onset of a disease or illness.