Virology 1

Question 1

Are viruses cells?

Answer 1

Not cell

Question 2

Are they capable of independent replication.?

Answer 2

Not capable

Question 3

Do they synthesize their own energy nor their own proteins?

Answer 3

No they don’t

Question 4

Can we see them in light microscope?

Answer 4

They are too small. No

Question 5

are ribosomes & mitochondria present in viruses

Answer 5

No, they are absent

Question 6

Are both DNA and RNA present in viruses

Answer 6

Its either DNA or RNA.

Question 7

How much (many or few) proteins are present in cell & viruses

Answer 7

Cell: many viruses: few.

Question 8

What lipoprotein membrane is present in some viruses?

Answer 8

Envelopeviruses

Question 9

How many enzymes are present in viruses

Answer 9

None or few

Question 10

Do viruses do binary fission to replicate

Answer 10

No

Question 11

Viruses range in size from _ to _

Answer 11

20nm to 300nm

Question 12

Most viruses appear in what shape under an electron microscope (2)

Answer 12

Spheres & rods

Question 13

What is a capsid?

Answer 13

All viruses have a protein coat that covers genome

Question 14

Capsid is composed of repeating subunits called

Answer 14

Capsomers

Question 15

The virus symmetric appearance used for

Answer 15

Classification

Question 16

Some viruses, capsid is covered with

Answer 16

Lipoprotein envelope

Question 17

What is nucleocapsid composed of

Answer 17

Nucleic acid genome & capsid proteins

Question 18

Viral nucleocapsids have 2 types of symmetry? Are they enveloped?

Answer 18

Spherical symmetry (enveloped or naked)
Helical symmetry (enveloped)

Question 19

Other name for spherical symmetry

Answer 19

Icosahedral symmetry

Question 20

The DNA and RNA genomes how many strands can they be?

Answer 20

Single or double

Question 21

Some RNA viruses have a___________ genome

Answer 21

Segmented

Question 22

Give 2 examples of RNA viruses

Answer 22

Influenza virus & rota virus

Question 23

All viruses have one copy of their genome except

Answer 23

Retroviruses has 2 copies

Question 24

Viral surface proteins mediate?

Answer 24

Attachment to host cell receptors

Question 25

The proteins accepting cell receptors determines What 2 things of the virus?

Answer 25

Determines host & organ specificity of virus

Question 26

Virus surface proteins are targets of?

Answer 26

Antibody which neutralizes viral replication

Question 27

How do viruses evade host defenses?

Answer 27

Some produce antigenic variants of their surface proteins

Question 28

What are the internal proteins in viruses

Answer 28

DNA or RNA polymerases

Question 29

What is the matrix protein Of virus?

Answer 29

Structural proteins linking viral nucleocapsid proteins& envelope proteins.

Question 30

Can antibody against one antigenic variant neutralize different serotypes?

Answer 30

It can not

Question 31

Viral envelope consists of

Answer 31

membrane that contains lipid derived from host cell & proteins encoded by virus,

Question 32

How is the viral envelope acquired? And what is the process called?

Answer 32

it is acquired as virus exits from cell in process called budding.

Question 33

Are enveloped viruses easily inactivated or not

Answer 33

EAsily inactivated

Question 34

Are naked viruses easily inactivated or not

Answer 34

- no they Survive longer in environment

Question 35

How are enveloped viruses transmitted?

Answer 35

Transmitted by direct contact via blood & body fluids.

Question 36

How are naked viruses transmitted?

Answer 36

Transmitted by indirect means e.g. fecal-oral route

Question 37

Viral growth curve one virion infects cell and what happens within hours?

Answer 37

One virion infects cell & hundreds of progeny virions are produced within hours.

Question 38

Remarkable Amplification explains _______ Spread of Virus from Cell to Cell

Answer 38

Rapid

Question 39

What is the Eclipse Period, and when does it occur

Answer 39

It is the time when no virus particles are detected within the infected cell & occurs soon after cell is infected.

Question 40

What Are the 5 steps of viral replication

Answer 40

1. Attachment 2. Penetration and uncoating. Re 3. Transcription & Translation 4. Assembly 5. Release

Question 41

For Attachment Virus particles can only infect cells possesing ___________________ specific to virus species

Answer 41

Surface receptors

Question 42

Naked viruses attach to cell with

Answer 42

Capsid

Question 43

Envelope viruses attach to cell with

Answer 43

Envelope proteins

Question 44

Viruses penetrate into cells by means of

Answer 44

Pinocytosis

Question 45

Another name of pinocytosis

Answer 45

viropexis

Question 46

In enveloped viruses envelope fuse with? And they release what?

Answer 46

Fuse with cell membrane, releasing virus into cytoplasm

Question 47

Absorption of such an enveloped virus to two cells at the same time results in

Answer 47

Cell fusion

Question 48

What does uncoating the 3rd step involve?

Answer 48

It involves release of nucleic acid from capsid

Question 49

What activates uncoating in viral replication (give an exception)

Answer 49

It is activated by cellular enzymes & contribution from cell membranes (except smallpox virus)

Question 50

Replication of nucleic acid: DNA viruses viruses are usually_________ stranded (give an exception)

Answer 50

Double stranded (except parvoviruses, single-stranded)