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Biology II > Chapter 21: Microbial Life - Viruses > Flashcards

Chapter 21: Microbial Life - Viruses Flashcards

(53 cards)

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1
Q

What is the Virus Structure

A

Nucleic Acid surrounded by a protein coat called a capsid

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2
Q

A virus does not have/cannot

A

cellular organelles
Metabolism
Growth
Reproduce through mitosis or meiosis

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3
Q

Viruses infect

A

bacteria
fungus
plants
animals

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4
Q

Viruses are Obligate Parasites, what does this mean?

A

Cannot metabolize or reproduce without a host cell.

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5
Q

The 4 components that make up a virus:

A
  • Viral Nucleic Acid genome.
  • Capsid (capsomeres, proteins that make up the capsid).
  • Glycoproteins that allow the virus to latch onto host cells.
  • Some viruses have a surrounding envelope made of host cell receptors.
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6
Q

What are the 4 general structure groups for a Viral Capsid? (also classified by their type of nucleic acid)

A
  • helical
  • icosahedral
  • enveloped
  • head-and-tail
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7
Q

What is the structure of a helical virus?

A

-Tubular protein capsid
- nucleic acid
- most plants are helical

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8
Q

What is the structure of an icosahedral virus?

A
  • sphreical protein capsid
  • most common virus family is adenovirus and poliovirus
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9
Q

What is the structure of an enveloped virus?

A
  • have enveloped from the host cell membrane
  • surrounds spherical capsid
  • able to rapidly adapt to the host
    -Ex.) Flu, Covid-19, HIV
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10
Q

What is the structure of a head-and-tail virus?

A
  • icosahedral head and helical tail
  • most are bacteriophages, infects bacteria
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11
Q

DNA/RNA Viruses can be..

A
  • can be single or double stranded
  • can be linear or circular
  • DNA/RNA are used as genetic material
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12
Q

Where is the Viral Genome located?

A

-contained within the viral core

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13
Q

Small genomes are genes for making more of what?

A
  • more DNA/RNA
  • proteins for capsids
  • replication proteins not available in host cells
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14
Q

Transcription

A

DNA is used as a template to make mRNA, the mRNA created is “+mRNA”, and the strand used as a template is “-DNA strand”

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15
Q

Translation

A

mRNA is the template for building a protein

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16
Q

Which strand can attach to a ribosome and be translated to create a protein?

A

+mRNA

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17
Q

What directs the host cell’s replication enzymes to replicate the viral DNA rather than the host cell’s DNA?

A

Viral nucleic acid DNA, and then transcribes and translate the viral DNA into viral protein.

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18
Q

Human DNA viruses include:

A

chicken pox, herpes, and HPV.

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19
Q

DNA VIRUSES (BALTIMORE
CLASSIFICATION) Group I

A
  • double-stranded DNA (dsDNA)
  • (+/-)dsDNA is a template for transcription of +mRNA
    -ex.) herpes simplex virus
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20
Q

DNA VIRUSES (BALTIMORE
CLASSIFICATION) Group II

A
  • +single-stranded DNA (+ssDNA)
  • must turn into dsDNA in order to make mRNA
  • ex,) canine parvovirus
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21
Q

What encodes for replication enzyme (RNA polymerase) that replicates viral RNA into +mRNA to be used for translation?

A

Viral nucleic acid RNA

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22
Q

In the retroviruses, the RNA encodes for enzymes that replicate…

Study These Flashcards
A

the viral RNA and DNA

23
Q

RNA polymerase is not a fastidious replication enzyme and often makes mistakes because:

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A

RNA viruses mutate more frequently than DNA viruses.
RNA viruses are able to readily adapt to their host.

24
Q

Examples of Human RNA viruses are

Study These Flashcards
A

measles, HIV, SARS-Covid 2

25
RNA VIRUSES (BALTIMORE CLASSIFICATION) Group III
-Double-stranded RNA - +mRNA is transcribed from dsRNA in a similar fashion to dsDNA - ex.) retrovirus
26
RNA VIRUSES (BALTIMORE CLASSIFICATION) Group IV
- +single-stranded RNA (+ssRNA) - +ssRNA can serve as the +mRNA, and an intermediate -ssRNA is created using the +ssRNA as a template which can be used to transcribe +mRNA -SARS-Cov 2
27
RNA VIRUSES (BALTIMORE CLASSIFICATION) Group V
- -single-stranded RNA (-ssRNA) - serves as the template to transcribe +mRNA - Rabies
28
RETROVIRUSES (BALTIMORE CLASSIFICATION) Group VI
- +ssRNA - Reverse transcription into -ssDNA, which is then used to make its own complimentary DNA, yielding dsDNA, which is inserted into host DNA. Then used to transcribe +mRNA (+ssRNA>-ssDNA>(+/-)dsDNA> mRNA) - HIV
29
RETROVIRUSES (BALTIMORE CLASSIFICATION) Group VII
- dsDNA transcribed to +ssRNA (that act as +mRNA) that is reverse transcribed to -ssDNA, then used to make dsDNA which are then inserted into host DNA. Then used to transcribe +mRNA((+/-)dsDNA comes apart and put back together to create +mRNA) - ex.) hepatitis B
30
Most viruses have ______ on surface capsid that are recognized by the host cell receptors.
glycoproteins
31
These cell receptors have normal cellular functions utilized by viruses.
- cell-cell recognition - enzymatic activity - cell-cell anchors
32
First two steps of the virus life cycle?
- attachment: a virus attaches to host cell by its receptor - penetration: capsid or nucleic acid penetrates through the cell
33
What are the 3 possible routes of entry?
-Virus binds to host membrane and injects its viral nucleic acid only into host cell cytoplasm. - Virus bonds to host membrane and fuses its membrane with plasma host membrane and transfers its viral nucleic acid into host cell cytoplasm - Virus binds to host membrane and entire virus is internalized by host cell
34
Uncoating
Viral contents are released into host cell
35
Replication
nucleic acid is replicated and mRNA is transcribed
36
Assembly
+mRNA is used to create viral enzymes, capsid proteins, and viral nucleic acid
37
Release
newly created viruses are released from the host cell.
38
What are the 6 steps of the viral lifecycle?
1. attachment 2. penetration 3. uncoating 4. replication 5. assembly 6. release
39
Lytic lifecycle in bacteriaphage
- bacteriophages infect only bacteria in domain bacteria, kingdom Archaea have similar viruses. -the release of viruses destroys the host cell in lytic cycle
40
Lysogenic lifecycle in bacteriophage
- bacteriophages infect only bacteria in domain bacteria, kingdom Archaea have similar viruses. - host cell is not destroyed in the lysogenic cycle. - Viral DNA becomes integrated as a prophage in bacterial host, latency occurs in Eukaryotic viruses.
41
_____, that infect plants & animals, can enter a ______ when they are not producing more viruses.
Eukaryotic viruses - latency period
42
After _____, virus settles in ______ and goes long periods of time w/ot producing new ones.
intial infection, - nerve tissue -ex,) herpes, HIV
43
Virus are specific to what they infect such as
- smallpox only infects human - plant viruses only infect plants. - rabies only infect mammals
44
Horizontal Transmission:
from one organism to another
45
Vertical Transmission:
- from patient to offspring - occurs mostly in plants -
46
In plants, the virus cannot penetrate cell wall unless ...
the cell wall is damaged. in plants, viral infections are secondary to mechanical damage.
47
Why can viruses infect animals easier than plants?
Animals do not have a cell wall.
48
____ work by teaching the immune system to recognize and build immunity to specific viruses or bacteria
Vaccines
49
_____ do not work on viruses, they treat infections.
Antibiotics
50
There are many types of vaccines including:
- live, attenuated- living but weakened version of virus. (MMR, smallpox, Chickenpox, yellow fever) - killed- entire virus killed (hepatitis A, flu, polio, rabies) - vaccines use subunits of the virus(nucleic acid, capsids, or other viral proteins) -mRNA vaccines such as flu, Zika, and rabies
51
What virus is enveloped, has an -ssRNA, and spherical shaped?
Influenza FLU
52
There are four types of influenza viruses:
- type A: humans, birds, and pigs causes illness and death. 75% of seasonal flu - type B: humans and seals, causes illness and death - type C: humans, dogs, and pigs, very mild and no death - type D: cows and pigs
53
Type A Influenza is divided into two surface proteins:
- hemagglutinin (H) 18 varient types - neuraminidase (N) 11 variants

Biology II (7 decks)

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