1/24 Kingsley Basic Virology Concepts - Structure and Function

Question 1

Viral size limits function, so they have _____ and are _____

Answer 1

• no intrinsic metabolism
• obligate intracellular parasites

Question 2

What is a virion?

Answer 2

Infective viral particle

Question 3

Non-enveloped viruses contain what structures?

Answer 3

Nucleocapsid and capsid

Question 4

What is a nucleocapsid?

Answer 4

Nucleic acid core

Question 5

What is a capsid?

Answer 5

Protein shell (contains the viral DNA inside)

Question 6

Enveloped viruses are derived from:

Answer 6

Host membrane

includes viral proteins in membrane lipids

Question 7

In enveloped viruses, the “envelope” is ____ to the nucleocapsid

Answer 7

External

Question 8

Viral capsid structure is often:

Answer 8

Pentamers or capsomeres

Question 9

Capsomere is a structural unit of:

Answer 9

(nucleo)capsid

Question 10

One of the functions of the viral capsid is delivery via ______

Answer 10

VAPs

Question 11

What are VAPs?

Answer 11

Viral attachment proteins

Question 12

_____ are naked and are released by cell lysis

Answer 12

Non-enveloped viruses

Question 13

_____ are released by budding

Answer 13

Enveloped viruses

Question 14

Enveloped viruses are less stable, so they must be:

Answer 14

Wet (must stay wet)

Question 15

All human helical viruses are:

Answer 15

Enveloped

Question 16

Viral envelope composition

Answer 16

• Host derived lipoproteins surround nucleocapsid
• Viral glycoprotein (peplomers, VAPs)

Question 17

Peplomers are ____ which have ____

Answer 17

Viral spikes; tissue specificity

Question 18

Viral glycoproteins (peplomers) may function as:

Answer 18

VAPs (viral attachment proteins)

Question 19

Examples of viral glycoproteins

Answer 19

• Hemagglutinins
• Neuraminidase

“H” and “N” of H1N1 influenza virus

Question 20

Neuraminidase enables ____ from cell by _____

Answer 20

Viral release; cleaving terminal neuraminic/sialic acid

Question 21

_____ has both hemagglutinins and neuraminidase

Answer 21

H1N1

Question 22

Viral recognition is dependent on:

Answer 22

• host range
• tissue tropism

Question 23

Why is host range important in viral recognition?

Answer 23

VAPs may restrict which host(s) is/are infected

Question 24

VAP-receptor may further restrict cell type that can be infected, due to:

Answer 24

Tissue tropism

Question 25

Capsid VAPs or envelope VAPs have:

Answer 25

Tissue tropism

Question 26

_____ viruses are sufficient to cause infection on their own

Answer 26

DNA and (+) RNA strand

Question 27

For RNA viruses, the _____ strand is sufficient to cause infection on its own

Answer 27

Positive (sense)

Question 28

For a (-) RNA virus, _____ is needed as an intermediate step to cause infection

Answer 28

RNA dependent RNA polymerase

Question 29

____ viruses can get into the nucleus, whereas ____ viruses cannot and stay in the cytosol

Answer 29

DNA; RNA

Question 30

Most human DNA viruses are:

Answer 30

dsDNA

Question 31

Human dsDNA viruses replicate in:

Answer 31

Nucleus

Question 32

Most human RNA viruses are _____

Answer 32

ssRNA

Question 33

Human ssRNA virus replication occurs in:

Answer 33

Cytoplasm

Question 34

Baltimore classification: Group II

Answer 34

single stranded DNA (ssDNA)

Question 35

Example of Group II virus

Answer 35

Parvovirus (ssDNA)

Question 36

Baltimore classification: Group III

Answer 36

Double-stranded RNA (dsRNA)

Question 37

Example of Group III virus

Answer 37

Rotavirus (dsRNA)

Question 38

Early phase of viral replication includes:

Answer 38

- recognize target cell - attach via receptors (capsid, envelope) - penetrate or cross plasma membrane - uncoat in cytoplasm or delivered to nucleus

Question 39

Late phase of viral replication includes:

Answer 39

- genome replication - viral protein synthesis - assembly - release (lysis, budding)

Question 40

Routes for viral uptake

Answer 40

- endocytosis - fusion - translocation (viropexis)

Question 41

____ viruses can be taken up by a cell via endocytosis

Answer 41

Naked or enveloped

Question 42

_____ is a route for successful infection for some viruses

Answer 42

Endocytosis

Question 43

Endocytosis may prevent:

Answer 43

Infection by other viruses

Question 44

What is fusion?

Answer 44

Envelope (of enveloped virus) merges with membrane to release capsid

Question 45

Fusion occurs in _____ viruses

Answer 45

Enveloped (only)

Question 46

Example of translocation mechanism

Answer 46

Viropexis

Question 47

What is viropexis?

Answer 47

- binding exposes hydrophobic structures - allows viral entry into host cell

Question 48

DNA viruses use _____ for transcription

Answer 48

Host DNA-dependent RNA polymerase II

Question 49

RNA viruses use _____ for transcription

Answer 49

viral RNA-dependent RNA polymerase

Question 50

DNA viruses use ____ for replication

Answer 50

Host DNA-dependent DNA polymerase

Question 51

RNA viruses use _____ for replication

Answer 51

Viral RNA-dependent RNA polymerase

Question 52

How are naked viruses released from the cell?

Answer 52

Lysis (sudden release)

Question 53

How are enveloped viruses released from the cell?

Answer 53

Budding (slow, gradual)