viruses

Question 1

where is the only place a virus can reproduce

Answer 1

in host cells

Question 2

T or F: viruses are alive

Answer 2

false; they’re not alive because they don’t meet all the requirements of living organisms

Question 3

list the reasons why viruses aren’t alive

Answer 3

they’re acellular, don’t respond to stimuli, don’t undergo metabolic reactions, and they don’t maintain internal conditions through homeostasis

Question 4

what nucleic acid type(s) can viruses have

Answer 4

ss DNA or ss RNA
ds DNA or ds RNA

Question 5

what surrounds the genome of a virus

Answer 5

a protein coat called a capsid

Question 6

what is a capsid

Answer 6

a protein coat that surrounds the genome of a virus

Question 7

what is the name of the proteins that make up the capsid

Answer 7

protomers

Question 8

what are the three types of capsid symmetry

Answer 8

helical, icosahedral, complex

Question 9

describe helical capsids

Answer 9

the protomers self-assemble in a helical/spiral arrangement to produce a rod structure

Question 10

give an example of a virus with helical capsid

Answer 10

tobacco mosaic virus

Question 11

describe icosahedral capsids

Answer 11

a polyhedron with 20 equilateral triangular faces and 12 vertices

Question 12

give an example of a virus with an icosahedral capsid

Answer 12

human papilloma virus (HPV)

Question 13

describe a complex capsid

Answer 13

they have complicated structures and may possess tails and other structures

Question 14

give an example of a virus with a complex capsid

Answer 14

T4 bacteriophage (they infect E coli)

Question 15

what layer do some bacteria have that surrounds the capsid

Answer 15

viral envelope

Question 16

what is the viral envelope made of

Answer 16

protein, lipids, and carbs

Question 17

what do some enveloped viruses have that project from the surface of the envelope

Answer 17

spikes

Question 18

what is a virus called that doesn’t have its capsid covered by an envelope

Answer 18

naked or nonenveloped

Question 19

advantage to having an envelope?

Answer 19

helps the virus to evade the host’s immune system

Question 20

disadvantage to having an envelope?

Answer 20

more sensitive to environmental conditions (ie antimicrobial agents)

Question 21

what is the highest taxonomic group for viruses

Answer 21

family

Question 22

list 4 ways viruses are grouped into families

Answer 22

type of nucleic acid, if it has an envelope or not, symmetry of the capsid, dimensions of the virion (fully formed virus)

Question 23

what do order names end in

Answer 23

virales

Question 24

what do family names end in

Answer 24

viridae

Question 25

what do subfamilies end in

Answer 25

virinae

Question 26

what do genus names end in

Answer 26

virus

Question 27

T or F: specific epithets are always used for viruses

Answer 27

false; they are not used

Question 28

since specific epithets aren't used for viruses, how instead are they named

Answer 28

species names are given by descriptive common names

Question 29

other than taxonomy, what is another system of how viruses are groups

Answer 29

the baltimore system

Question 30

describe the baltimore system

Answer 30

viruses are placed into 1 of 7 groups based upon the type of genome they have + their replication strategy

Question 31

list the 6 steps of the lifecycle of an animal viruses

Answer 31

attachment, entry, uncoating, biosynthesis, assembly, release

Question 32

describe attachment of an animal virus lifecycle

Answer 32

through random collision, animal viruses attach to their receptors on the host cell's surface

Question 33

describe entry of an animal virus lifecycle

Answer 33

1. endocytosis (most common), used by enveloped and non enveloped 2. fusion, only used by enveloped

Question 34

describe uncoating of an animal virus lifecycle

Answer 34

separation of the nucleic acid from the capsid

Question 35

describe biosynthesis of an animal virus lifecycle

Answer 35

the virus takes over the host cell and uses its enzymes + ribosomes to replicate its own DNA and make its capsid proteins

Question 36

describe assembly of an animal virus lifecycle

Answer 36

everything is put together

Question 37

describe release of an animal virus lifecycle

Answer 37

nonenveloped: causes lysis to the host membrane = host dies enveloped: released by budding

Question 38

how does an envelope protect the virus from the host's immune system

Answer 38

the immune response is unable to recognize it as forgein

Question 39

list 3 types of viral infections

Answer 39

acute, latent, chronic

Question 40

what is an acute infection

Answer 40

rapid onset, lasts for a short period of time

Question 41

example of acute infection

Answer 41

influenza virus

Question 42

what is a latent infection

Answer 42

the viruses have the ability to remain formant after the initial infection, and can become reactivated later

Question 43

example of a latent infection

Answer 43

herpes simplex virus

Question 44

how is herpes simplex virus reactivated (it's a latent infection)

Answer 44

due to stress, sunburn, hormones, trauma

Question 45

other than HSV, give another example of a latent infection

Answer 45

chicken pox

Question 46

which virus is chicken pox

Answer 46

a herpes virus: HSV-3

Question 47

what is chicken pox reactivated to form

Answer 47

shingles

Question 48

what is a chronic infection

Answer 48

these are reactions that occur over a long period of time. Amount of virus gradually builds up. They are usually fatal

Question 49

example of chronic infection

Answer 49

measles virus

Question 50

why is measles chronic

Answer 50

in some children, it can lead to an infection of the brain called SSPE (subacute sclerosing panencephalitis; Dawson's disease)

Question 51

T or F: some viruses can cause cancer

Answer 51

true

Question 52

give an example of viruses that can cause cancer

Answer 52

hepatitis B or C, HPV