Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Intro to Microbio > Ch. 13 > Flashcards

Ch. 13 Flashcards

1
Q

Why are viruses nonliving?

A

They cannot reproduce on their own

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is defined as the number of different host cells that virus can infect
- limited to single bacterial species for a single phage or virus

A

Host range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What 4 factors limit host range

A
  1. attachment to host receptors
  2. host attachment sites
  3. bacteriophages
  4. animal viruses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

T or F once one virus enters a host cell no other viruses can enter?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the 3 general characteristics of viruses?

A
  1. Non-living entities
  2. infect organisms of every domain
  3. referred to by organism they infect (Animal viruses, Plant viruses, Bacteriophage)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Who first proposed the term virus?

A

Louis Pasteur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. what is a virion?
  2. Virions can have DNA, RNA, or both?
A
  1. complete, fully developed viral
    particle
  2. Can have DNA or RNA, never both
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

math the virion structure to its definition (envelope, nucleic acid, spikes, capsid):

  1. DNA or RNA can be single- or
    double-stranded; linear or circular
  2. protein coat made of capsomeres
    (subunits)
  3. lipid, protein, and carbohydrate
    coating on some viruses.
    - Partially formed from the plasma membrane of the host cell when the virus buds from the cell
  4. projections from outer surface
    - found on some enveloped viruses
    ▪ Made of carbohydrate and protein
    ▪ May be used for attachment
A
  1. Nucleic acids
  2. capsid
  3. envelope
  4. spikes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 2 phases in Obligate intracellular parasites? Which one is metabolically inert and active?

A
  1. extracellular phases (inert)
  2. Intracellular phase (active)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which is more resistant to killing, naked virus or envelope virus?

A

Envelope virus because they have a plasma membrane that is more susceptible.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

does multiplication take place inside or outside of the host cell during the replication cycle?

Viruses use host machinery to support __________

A

inside a host cell

reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

T/F Viral genome is DNA and RNA

A

FALSE, it is either DNA OR RNA, never both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

complete complex of nucleic acid and protein packaged in the virion

A

Nucleocapsids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Determine which type of virus this is based on the characteristics below:

  • Have membrane surrounding nucleocapsid
  • Lipid bilayer with embedded proteins
  • Lipid bilayer with embedded proteins
  • Common in Animal viruses
  • Envelope makes initial contact with host cell
A

Enveloped Viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

T/F Complex viruses are virions composed of several parts with separate shapes and symmetries

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In comparison to bacterial cells viruses are what?

A

very small in size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the Two alternative mechanisms of multiplication of bacteriophages?

A
  1. Lytic cycle
  2. Lysogenic cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  1. which viral symmetry has spherical viruses? (e.g., human papillomavirus)
  • Most efficient arrangement of subunits in a closed shell
A
  1. Icosahedral viral symmetry
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

________ __________: causes lysis and death of the host cell
_________ __________: Phage DNA is incorporated in the host DNA

A
  1. Lytic cycle
  2. lysogenic cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q
  1. which cycle (lytic or lysogenic) involves productive infection?
  2. when there is a lysis of cells and release of virions what happens to the host cell?
  3. when there is a release of virions and non-lysis of cells what happens to the host cell?
A
  1. Lytic cycle
  2. It dies
  3. host cell burst (multiplies), continuous leakage of virions
21
Q
  1. In which cycle (lytic or lysogenic) does the nucleic acid of virus become part of host cell DNA or replicates as a plasmid?
  2. What is the state of the host cell being described above?
  3. At the end of the lysogenic cycle what happens to the host cell?
A
  1. Lysogenic cycle
  2. Latent state
  3. modified and continues to multiply
22
Q

What are the 3 potential outcomes of lysogeny?

A
  1. immune to reinfection (depending on external conditions)
  2. Phage conversion: host cells exhibit new porperties
  3. Specialized transduction: Changes genetic properties of the recipient bacteria
23
Q

what happens in lysogeny (latency)?

A

phage remains latent; no lysis of host cell (non-productive cycle)

24
Q
  1. Lysogeny begins like the lytic cycle
    ▪ Adsorption
    ▪ Penetration, then
    * _______________
  2. Inserted phage DNA is known as a what?
  3. T or F, the host cell replicates its chromosome but not its prophage DNA
A
  1. Incorporation
  2. prophage
  3. False, replicates its chromosome AND prophage DNA
25
Q

How do bacteriophages get nucleotides and amino acids if they don’t have any metabolic enzymes?

A

from the hosts

26
Q

Vibrio cholerae produces toxin and is capable of causing cholera only when it is lysogenic. What does this mean?

A

virus came from the genome which is why it becomes pathogenic

27
Q

In the attachment stage of VIRULENT INFECTIONS of bacteriophages and animal viruses what is the difference?

A

animal viruses: fusion of viral envelope and host membrane.

Bacteriophages: No fusion occurs in bacteriophages

28
Q

In the entry stage of VIRULENT INFECTIONS, what enters the cell in bacteriophages? animal viruses?

A

Bacteriophage: only nucleic acid
animal: entire virion cell including enzymes

29
Q

Animal viruses

  1. where do DNA viruses replicate their DNA using host enzymes?
  2. Where do they synthesize capsid proteins using host cell enzymes?
A
  1. nucleus of the host
  2. cytoplasm
30
Q

What does the outcome of infection of eukaryotic cells depend on?

A

factors independent of cell

31
Q

In bacteriophages and animal viruses is Targetting of virion necessary? if so what occurs?

A

Bacteriophage: unnecessary
animal: yes, site of replication

32
Q

Where does the uncoating stage of VIRULENT INFECTIONS take place in Bacteriophages and animal viruses?

A

bacteriophages: surface of cell
animal: inside cell

33
Q

_______ _______ has the same pattern of replication as phage with the same genome, (bacteriophages or animal viruses)

A

animal viruses

34
Q

When viruses may develop relationships with normal hosts but no obvious disease or damage is caused to host this is referred to as?

A

State of balanced pathogenicity

35
Q

Relationships between viruses and host are divided into what two categories?

A
  • Acute
  • Persistent
36
Q

Persistent infections can be divided into what 3 categories?

A

– Latent infections
– Chronic infections
– Slow infections

37
Q

T/F in acute infections Host cells usually die and may or may not lyse to release
virions

A

TRUE

38
Q
  1. In which type of infection can the Infectious virus be detected at all times?
  2. T or F Disease may be present or absent during extended times or may develop late in chronic infections?
  3. After the initial infection with or without disease symptoms, what happens to the virus?
  4. Best known example of a chronic infection?
A
  1. Chronic infections
  2. True
  3. Virus is released from host with no symptoms
    • Hepatitis B– a.k.a serum hepatitis
39
Q

In latent infections, infection is followed by what?

A

symptomless period

40
Q

Hep B, Hep C, and Rubella virus are all what type of infections?

A

Chronic infections

41
Q

What is responsible for most virus-induced tumors in humans?

Cancers caused by DNA viruses result from what?
-is growth controlled or uncontrolled?

A

Double-stranded DNA viruses

integration of viral genome onto host DNA
- uncontrolled growth

42
Q
  1. In slow infections the Infectious agent gradually increases in amount over a (short or long) period of time with no significant symptoms apparent during this time
  2. T or F Few infectious agents cause slow infections?
A
  1. Long
  2. True
43
Q
  1. What is a viroid?
  2. What do viroid’s consist of?
  3. What do viroid’s not have that allows them to be resistant to protease?
A
  1. group of pathogens much smaller
    and distinctly different from viruses
  2. small single-stranded RNA molecule
  3. no protein coat
44
Q

Define virion

A

Mature virus particle that is infectious

45
Q

In persistent infections, how are viruses released?

A

budding

46
Q

________: a protein and genome

_________: a single stranded RNA molecule (contains NO protein)

A

Virion
Viroid

47
Q

Define proteus

Are virions or viroids more susceptible to proteus?

A

An enzyme that destroys protein

Virions because they contain proteins

48
Q

Define prions

T/F prions cause brain degeneration

A

Proteinaceous infectious agent (infectious proteins)

TRUE

49
Q

What is a method for studying viruses?

A

cultivation of host

Intro to Microbio (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions