Viruses

Question 1

These are obligate intracellular parasites of living but non-cellular nature. They are inert outside of the cell.

Answer 1

Viruses

Question 2

Viruses are recognized by the ______ they cause.

Answer 2

diseases

Question 3

Viruses contain:

Answer 3

1. Single type of nucleic acid (DNA or RNA)
2. Protein coat (around the nucleic acid)
3. Spikes

Question 4

Viruses multiply inside living cells by using the _______ of the host cell.

Answer 4

synthesizing machinery

Question 5

Determined by specific host attachment sites and cellular factors.

Answer 5

Host range

Question 6

Spectrum of host cells the virus can infect.

Answer 6

Host range

Question 7

Viruses that infect bacteria.

Answer 7

Bacteriophages or phages

Question 8

A fully developed infectious viral particle composed of nucleic acid and surrounded by a protein coat outside a host cell.

Answer 8

Virion

Question 9

Protects the nucleic acid.

Answer 9

Capsid

Question 10

Protein subunits making up the capsid.

Answer 10

Capsomeres

Question 11

These covers the envelop to attach to host cells.

Answer 11

Spikes

Question 12

Viruses must be grown in _______. They are never grown in culture media.

Answer 12

living cells

Question 13

Bacteriophages form _______ on a lawn of bacteria.

Answer 13

plaques

Question 14

Animal viruses may be grown in:

Answer 14

living animals or in embryonated eggs

Question 15

Viral Taxonomy:

Answer 15

1. Nucleic Acid
2. Morphology
3. Strategy for replication
4. Symptoms

Question 16

Group of viruses sharing the same genetic information and ecological niche (host).

Answer 16

Viral species

Question 17

Used for naming the species.

Answer 17

Common names

Question 18

Designates the subspecies.

Answer 18

Number

Question 19

For a virus to multiply, it must invade a host cell and take over the host’s:

Answer 19

metabolic machinery

Question 20

This process can drastically change the host cell and usually causes its death.

Answer 20

Viral Multiplication

Question 21

A viral replication cycle where the virus immediately takes over the host, replicates, and destroys the cell.

Answer 21

Lytic cycle

Question 22

Viral DNA behavior in the Lytic cycle:

Answer 22

Does not integrate into host DNA; remains separate

Question 23

Host cell fate in the Lytic cycle:

Answer 23

Host cell bursts (lysis), releasing new viruses

Question 24

Replication method of the Lytic cycle:

Answer 24

Viral DNA directs the cell to produce new virus particles immediately

Question 25

Speed of infection in the Lytic cycle:

Answer 25

Fast (virus rapidly produces offspring)

Question 26

Trigger for transitition:

Answer 26

No transition

Question 27

A viral replication cycle where the viral DNA integrates into the host genome and remains dormant before activation.

Answer 27

Lysogenic cycle

Question 28

Viral DNA behavior in the Lysogenic cycle:

Answer 28

Integrates into host DNA; becomes a prophage (dormant virus)

Question 29

Host cell fate in the Lysogenic cycle:

Answer 29

Host cell remains intact and continues spreading the viral DNA

Question 30

Replication method of the Lysogenic cycle:

Answer 30

Viral DNA is copied when the host cell divides, spreading the virus silently

Question 31

Speed of infection of the Lysogenic cycle:

Answer 31

Slow - Virus remains dormant until triggered

Question 32

Trigger for transition of the Lysogenic cycle:

Answer 32

External factors can trigger the switch to the lytic cycle

Question 33

Lysogenic cells become immune to reinfection by the same ____.

Answer 33

phage

Question 34

Host cell exhibits new properties.

Answer 34

Phage conversion

Question 35

They are encoded by a prophage:

Answer 35

1. C. botulinum toxin 2. E. coli Shiga toxin

Question 36

A prophage is excised from the host cell carrying bacterial DNA with it.

Answer 36

Specialized transduction

Question 37

Mechanisms of Animal Viruses:

Answer 37

1. Attachment 2. Entry 3. Uncoating 4. Biosynthesis

Question 38

Mutated gene of animal cells; can convert a cell into a tumor cell.

Answer 38

Oncogene

Question 39

Viruses capable of inducing tumors in animals. After being transformed by viruses, these have tumor specific transplantation antigen (TSTA) on the cell surface; or T antigen in the nucleus.

Answer 39

Oncoviruses

Question 40

Infect and lyse cancer cells.

Answer 40

Oncolytic viruses

Question 41

Examples of DNA viruses:

Answer 41

1. Adenoviridae 2. Herpesviridae 3. Poxviridae 4. Papovaviridae 5. Hepadnaviridae

Question 42

Examples of RNA viruses:

Answer 42

1. Retroviridae - Human T cell leukemia viruses (HTLV 1, HTLV 2)

Question 43

Virus remains in asymptomatic host cell for long periods (Cold sores, shingles).

Answer 43

Latent viral infections

Question 44

Disease processes occurs over a long period, generally fatal (Subacute sclerosing panencephalitis/measles virus).

Answer 44

Persistent viral infections

Question 45

For proteinaceous infectious particle.

Answer 45

Prion

Question 46

Diseases caused by prions:

Answer 46

1. Mad cow disease 2. Creutzfeldt-Jakob disease

Question 47

Nine diseases are caused by prions, they are:

Answer 47

Transmissible Spongiform Encephalopathies (TSE)

Question 48

Resemble animal cells; can possibly infect insects.

Answer 48

Plant viruses

Question 49

Entrance of plant viruses:

Answer 49

plant wounds

Question 50

Short pieces of naked RNA that can cause plant diseases.

Answer 50

Viroids