LO2

Question 1

Why are Viruses not considered alive?

Answer 1

• because they are missing cellular components
• cant reproduce without a host cell
• cant make their own proteins
• cannot independently perform metabolic process

Question 2

Why would viruses be considered living to some people?

Answer 2

• they respond to stimuli
• they evolve and adapt to their envirionment

Question 3

What domain of life are viruses apart?

Answer 3

theyre not classified within any of the domains of life

Question 4

What is the structure of a virus?

Answer 4

they have a core of nucleic acid surrounded by a capsid

Question 5

What is the genome in a virus?

Answer 5

a single or double-straned RNA or DNA

Question 6

definition: a protective protein coat

Answer 6

capsid

Question 7

What shape is the capsid normally?

Answer 7

helical or polyhedral

Question 8

What does it mean if a virus is enveloped?

Answer 8

when the virus leaves it’s host cell it takes some of the host’s plasma membrane

Question 9

definition: bind to a complementary receptor on the surface of a host cell and allow the virus to gain entry

Answer 9

glycoproteins

Question 10

Viruses are measures using __________

Answer 10

nanometers

Question 11

What can you use to view viruses?

Answer 11

electron microscope

Question 12

definitions: viruses that infect bacteria

Answer 12

bacteriophages

Question 13

what is the shape of bacteriophages

Answer 13

they have a polyhedral capsid and a helical tail at the bottom

Question 14

definition: helps bacteriophage penetrate the bacterial host

Answer 14

helical tail

Question 15

definition: using bacteriophages can be used to treat bacterial infection in cases of antibiotic resistance

Answer 15

phage therapy

Question 16

What are the stages of the lytic reproductive cycle

Answer 16

attachment, penetration, replication and synthesis, assembly, and release

Question 17

definition: the virus attaches to specific receptors on the host cell’s plasma membrane

Answer 17

attachment

Question 18

definition: the virus penetrates the host cell’s plasma membrane and moves into the cytoplasm

Answer 18

penetration

Question 19

definition: stage when virus uses the host cell’s enzymes and ribosomes to copy its viral genome and proteins

Answer 19

replication and synthesis

Question 20

definition: stage when newly made viral components are assembled into complete viruses

Answer 20

assembly

Question 21

definition: stage when the cell is lytic and destroys host cell’s plasma membrane and viral particles are released all at once

Answer 21

release

Question 22

lytic is referring to which process of the lytic cycle

Answer 22

release

Question 23

definition: cycle after attachment and penetration the virus integrates its genome into the host’s genome indefinitely

Answer 23

lysogenic cycle

Question 24

definition: inactive

Answer 24

latent

Question 25

what happens during the lysogenic cycle?

Answer 25

- viral genes are replicated

Question 26

definition: the integrated virus

Answer 26

prohpage

Question 27

what could cause the prophage to become lytic?

Answer 27

certain environmental conditions like UV radiation

Question 28

definition: when the host cell may exhibit new properties when it is infected with a prophage

Answer 28

lysogenic conversion

Question 29

what is an examples of lysogenic conversion

Answer 29

bacteria clostridium botulinum only causes botulism when it is infected with a prophage

Question 30

What are examples of lysogenic viruses

Answer 30

Herpes (genital herpes and cold sores), varicella-zoster virus(chicken box, shingles), and HPV(warts)

Question 31

What are lysogenic viruses triggered by?

Answer 31

a compromised immune system

Question 31

animal viruses are host and sometimes tissue _______?

Answer 31

specific

Question 31

How do viruses enter animal host cells

Answer 31

by fusing with the host plasma membrane or endocytosis

Question 31

What happens only in animal viruses?

Answer 31

host cells will actively envelope viruses by endocytosis

Question 32

which components of a virus and which component of a host are responsible for the specificity between a virus and its host

Answer 32

glycoproteins and cell surface receptors

Question 33

During which step of the viral life cycle is specificity enforced?

Answer 33

during the attachment and penetration steps

Question 34

definition: the taking in of matter by the membrane and creating a vacuole

Answer 34

endocytosis

Question 35

What are some animal virus infection outcomes?

Answer 35

- viral information into tumor cells - host cell lysis via the lytic cycle - host cell is not killed

Question 36

definition: these infections result when new viral particles are released slowly and the host cell does not die

Answer 36

persistent infections

Question 37

definitions: infections that are persistent and have periods of viral inactivity during the lysogenic phase

Answer 37

latent infections

Question 38

definitions: animal RNA viruses that use reverse transcriptase to convert their RNA genome into a DNA intermediate

Answer 38

retroviruses

Question 39

definition: a special DNA polymerase

Answer 39

reverse transcriptase

Question 40

In retroviruses the DNA genome does what

Answer 40

integrate with the host genome

Question 41

what are examples of retroviruses?

Answer 41

HIV and certain cancer-causing viruses

Question 42

retroviruses have what kind of genome before infecting a host cell

Answer 42

RNA

Question 43

What is the funciton of reverse transcriptase

Answer 43

converts RNA genome to DNA intermediate

Question 44

What are the steps of the retroviral infection cycle

Answer 44

Steps 1-3: retroviral RNA genome converted to DNA genome Step 5:integration Step 6: activation and retroviral RNA is transcribed to DNA Step 7: retroviral mRNA codes for new viral proteins Step 8: proteins are assembled and then exit host cell

Question 45

definition: how viruses mutate rapidly and exchange genetic material

Answer 45

recombination

Question 46

definition: viruses that infect humans but originated from animals and then spread to humans

Answer 46

zootonic viruses

Question 47

How do zoonotic viruses spread to humans

Answer 47

mutation or recombination