ch 17 Flashcards
(115 cards)
1
Q
_____ are infectious agents that are must have a host.
They lack machinery to make proteins, but they hijack the machinery of their host.
All of these agents contain a nucleocapsid, a nucleic acid, and a capsid. They are incapable of metabolism, replication or motility.
A
Virus
2
Q
_____ viruses contain a ssDNA or dsDNA in nucleocapsid.
- dsDNA may directly be used for transcription and replication.
- ssDNA must form a dsDNA intermediate before it is used.
A
DNA viruses
3
Q
_____ viruses contain either ssRNA or dsRNA in nucleocapsid.
- RNA polymerase must be encoded before replication because cell hosts do not contain an enzyme that can make RNA from an RNA template.
A
RNA viruses
4
Q
Twort and d’Herelle discovered agents too small to be seen with a light microscope, passed through filters and only grew in cell-containing media.
This agent was first called the “_____ virus”, the term was later dropped.
A
Filterable
5
Q
Virus means “_____,” a term once applied to all infectious agents.
A
poison
6
Q
If a virus is found outside a cell host, its called a _____. This also applies when describing physical attributes of a virus particle.
A
virion
7
Q
In a virion, the _____ is a protein coat, with capsomeres. They all protect the nucleic acid from enzymes, toxic chemicals and may carry enzymes required for infection of host cells.
A
Capsid
8
Q
At a minimum, the _____ is a particle that consists of a nucleic acid surrounded by a protein coat. Found outside the host cell.
A
Virion
(viral particle)
9
Q
The _____ is the combination of a viral genome and viral capsid.
A
nucleocapsid
10
Q
A type of phage called the _____ infects bacteria.
Most are non-enveloped, a large variety of shapes, genomes, and replication strategy.
A
Bacteriophages
(phages, [phages, eat])
11
Q
Bacteriophages are used as a _____ organism since they’re;
- easy to cultivate
- helps understand molecular biology
- ecosystems
- horizontal gene transfer
- limit bacteria growth
- medical applications
- food production
- storage applications
A
Model
12
Q
_____-proteins are structural protein created by phages, that are synthesized by the end of the cycle of infection. Examples (a capsid, tail, etc).
A
Late-Proteins
13
Q
_____ - _____ is the number of phage particles released.
A
Burst-Size
14
Q
______ phage have the option of either directing a lytic infection or incorporating DNA into host cell genome.
A
Temperate Phages
15
Q
In a virion, the capsid contains _____, the identical protein subunits arranged in a precise manner.
A
Capsomeres
16
Q
_____ virus have a lipid-bilayer outside the capsid, obtained from the host cell.
A
Enveloped viruses
17
Q
In viruses, the _____ protein layer that is fond between the nucleocapsid
(nucleic acid + capsid) and the envelope.
A
Matrix Protein
18
Q
_____ - _____ virus that does not have an envelope, a lipid-bilayer outside the capsid.
A
Non-Enveloped Viruses
(Naked Viruses)
19
Q
_____ are types of proteins that allow virions to attach (absorb) to specific receptor sites on a host. They stick out from either the lipid bilayer or capsids.
A
Attachment Protein
20
Q
_____ _____ is a type of binding between host cell and virion proteins. Binding allows entry of viral genome into a host cell, allowing signaling pathways or infection.
A
Viral attachment
21
Q
_____ are protein structures in Phages.
A
Fibers
22
Q
_____ are structures in Animal viruses.
A
Spikes
23
Q
Viruses have one of these three shapes,
the _____ shape appears symmetrical, polyhedral, spherical, but the surface is actually 20 flat triangles like a soccer-ball.
A
Icosahedral
24
Q
Viruses have one of these three shapes,
the _____ shape appears cylindrical but their capsomers are arranged in a helix, like a spiral staircase.
A
Helical
25
Viruses have one of these three shapes;
the _____ shape(s) are more **complicated**, like phages.
Complex
26
Viruses are inert particles, incapable of \_\_\_\_\_\_, replication, or motility. **Unless** in the **active state**, where they manipulate the **cellular function of the host**.
Metabolism
27
Virons do not **generate** or **store** \_\_\_\_\_, but **viruses** derive this type of **energy** from the **host cell**.
ATP
28
A _____ infection is likely to occur if host cell **slows growth**. Temperate phage **incorporates DNA** within the **host**, **without** **causing damage**. The prophage is replicated along with host cell chromosome.
Lysogenic Infection
29
A _____ bacteria cause **lysogenic infections**. If another lambda phage injects DNA into a lambada lysogen, the DNA will not be expressed, this is known as **immunity to superinfection**.
Lysogen
30
Lysogenic \_\_\_\_\_, the change in the **phenotype** of host cell genome by lysogens, which bacteriophages may encode toxins.
Lysogenic Conversion
31
The _____ is the genetic material of a bacteriophage, incorporated into the genome of a bacterium and able to produce phages if specifically activated.
Prophage
32
A _____ protein, which **phages** **carry** **prevent** **expression** of the genes required for **excision** and essential for **the lysogenic state**.
Repressor
33
The \_\_\_\_\_cycle from the entry of phage nucleic acid to exit takes 30 minutes.
Phage Cycle
34
The (1) step in the phage cycle, \_\_\_\_\_\_, is where the Phage particles attach with host cells at random; the protein on phages tail attaches to a receptor of host cell surface or appendage, exploiting entrance;
Attachment
35
The (2) step in the phage cycle, ______ \_\_\_\_\_\_ includes a feature all viruses have, where the nucleic acid is separated from the virus's protein coat before replication.
Genome Entry
36
The (3) in the phage cycle, ______ the Phage takes over control of host metabolism within minutes of Phage DNA entrance. Early viral proteins are synthesized and transcribed, such as Nuclease and Phage Proteins. Host gene expression is stoped, reaming host proteins continue to function. At the end cycle, late proteins are synthesized.
Synthesis
37
The (4) step in the phage cycle, ______ is where the synthesized late proteins begin are assemble new phage particles. DNA is packed into the phage head after they self-assemble or assemble with scaffolding proteins that are not part of the Phage Structure.
Assembly (maturation)
38
The (5) step in the phage cycle, ______ is a late infection, lysozyme is produced in Phages, the enzyme digests host cell wall within, causing the cell to lyse and ultimately releasing Phages. Lastly infecting susceptible cells and replication is repeated.
Release
39
Non-enveloped virions enter by receptor-mediated \_\_\_\_\_\_. Uncoating releases the nucleic acid from the protein coat.
endocytosis
40
In animal viral replication, this step is #\_\_\_\_\_\_, the **synthesis of viral proteins and replication**, of the Genome.
## Footnote
* DNA viruses generally replicate in the nucleus and use the host cell machinery for DNA synthesis as well as gene expression, although they often encode their own DNA polymerase.
* Replication of ssDNA viruses is similar to that of double-stranded DNA viruses, but the complementary strand must be synthesized first. RNA viruses usually replicate in the cytoplasm.
* Replication requires a virally encoded replicase to synthesize the complementary RNA strand. This enzyme lacks proofreading ability and makes more mistakes in replication than DNA polymerase. Reverse-transcribing viruses encode reverse transcriptase, which synthesizes DNA from an RNA template.
* As with replicas, these enzymes are error-prone.
3
41
In animal viral replication, this step is #\_\_\_\_\_\_, are **assembly and maturation**, Capsids are formed, and then the genome and any necessary proteins are packaged within it. The process may take place in the cytoplasm, nucleus, or in a variety of organelles.
4
42
In animal viral replication, this step is #\_\_\_\_\_\_, is **Release.**
Enveloped virions most often exit by budding. Non-enveloped virions are released when the host cell dies.
5
43
In animal viral replication, this step is #\_\_\_\_\_\_, **attachment**.
Attachment proteins or spikes on the viral particle attach to specific receptors on the cell surface.
1
44
In animal viral replication, this step is #\_\_\_\_\_\_, are **Penetration and Uncoating**. In the case of animal viruses, the entire virion enters the cell. Enveloped viruses either fuse with the host membrane or are taken in by receptor-mediated endocytosis.
2
45
**Synthesis** is the #**\_\_\_\_\_\_** step in the viral replication of bacteriophages.
3
46
**Genome Entry** is the **#\_\_\_\_\_\_** step;
in the viral replication of bacteriophages.
2
47
**Release** is the #\_\_\_\_\_\_ step;
in the viral replication of bacteriophages.
5
48
**Attachment** is the #**\_\_\_\_\_\_** step;
in the viral replication of bacteriophages.
1
49
**Assembly (maturation)** is the #\_\_\_\_\_\_ step;
in the viral replication of bacteriophages.
4
50
This type of _____ host lacks the **receptor** used by a given phage are **resistant to infection** by the specific phage.
Cells
51
In the first step of generalized infections of Animal Virus Replication is Attachment, where animal viruses enter the cell, go through uncoating process, but Bacteriophage receptors are \_\_\_\_\_\_. This process is not needed for bacteriophage since only the nucleic acid enters the bacterial cell and not the entire vision.
Unrelated
52
\_\_\_\_\_ is the process where **nucleic acid** **separates** from **capsid**.
Uncoating
53
\_\_\_\_\_ is the release mechanism out of the cell depends whether virion is enveloped, most enveloped viruses are released by a process where virus acquires its envelope.
Budding
54
In one of the three types of RNA genomes, _____ genome is the positive single-stranded RNA.
(+) ssRNA
55
In one of the three types of RNA genomes, the _____ genome is the negative single-stranded RNA.
(-) ssRNA
56
In one of the three types of RNA genomes, the _____ is double-stranded RNA.
dsRNA
57
(+) ssRNA can act like \_\_\_\_\_, so the viral genome can be directly translated by a host ribosome as soon as it enters the cell.
mRNA
58
(-) ssRNA (like influenza and rabies) must first make a complimentary (+) ssRNA strand from the _____ ssRNA strand template.
negative
59
(-) ssRNA (like influenza and rabies) must first make a complimentary (+) ssRNA strand from the (-) ssRNA strand template. That means (-) ssRNA virus must bring their RNA directed RNA polymerase enzyme in their ______ so they can use it once they enter the cytoplasm.
Capsid
60
\_\_\_\_\_essay routinely used to quantitate phage particle in samples in sewage, seawater and soil. The essay consists of a double layer agar, the soft agar is inoculated with both host and phage specimens, then poured over surface.
Plaque assay
61
\_\_\_\_\_ are the circular zones of clearing, form in the lawn due to cell lysis caused by the phage. Each represents a PFU.
Plaque
62
Viral _____ infections in animals characterized by sudden onset of symptoms of relatively short duration.
Acute Infections
63
Viral _____ infections in animals that can continue with or without symptoms for years or even the life of the host.
Persistent Infections
64
\_\_\_\_\_ infections in animals
that is characterized by the continued production of low levels of viral particles. If infected cell survives, it releases viral particles slowly. If infected cell lysis, and if a small proportion of cells infected at any given time results in a low number of viral particles continuously released.
Chronic Infections
65
Viral _____ infection, where the viral genome remains silent with a host cell, yet it can reactivate to cause productive infection. If viruses do not integrate into a host cell, chromosome, then they replicate independently of the host genome.
Latent Infections
66
Hepatitis B Virus
is a ______ infection. The cells involved include hepatocytes (liver cells). Disease symptoms are hepatitis, cirrhosis, hepatocellular carcinoma.
chronic
67
HCV (Hepatitis C Virus)
is a ______ infection. The cells involved include hepatocytes (liver cells). Disease symptoms are Hepatitis, cirrhosis, hepatocellular carcinoma.
Chronic
68
HSV-1 is a _____ infection.
| (Herpes Simples Virus Type 1)
Latent
69
HSV-2
is a _____ infection.
The cells involved include neurons of sensory ganglia. Disease symptoms are genital herpes and recurrent genital herpes.
(Herpes Simples Virus Type 2)
Latent
70
VZV
is a ______ infection. The cells involved include satellite cells of sensory ganglia. Disease symptoms are chicken box and shingles.
(Varicella Zoster, Herpesviridae family)
latent
71
CMV
is a _____ infection. The cells involved include salivary glands, kidney epithelium, leukocytes. Disease symptoms are pneumonia, eye infections, mononucleosis, congenital infections.
(Cytomegalovirus, Herpesviridae family)
latent
72
EBV
is a ______ infection. The cells involved include B-cells which are involved in antibody production. Disease symptoms are Burkitt's lymphoma.
(Epstein-Bar Virus)
latent
73
HIV
is a _____ infection. The cells involved include activated helper T cells, macrophages. Disease symptoms are AIDS.
(Human immunodeficiency virus)
chronic
74
HIV
is a _____ infection. The **difference here** is that the memory helper T-cells are affected.
(Human immunodeficiency virus)
Latent
75
The _____ is the silent viral genome cannot be eliminated from the body.
Provirus
76
\_\_\_\_\_ Viruses,
carry specific genes, which are similar to DNA sequence to proto-oncogenes.
They lead to tumor formation. Mast majority of viruses that cause cancer is due to mutations in host genes. 15 HPV’s are associated with cancers.
Oncogenes
77
The suffix of animal viruses families
that come from a variety of sources. Italicized, follows no consistent pattern. Prefixes in some cases are descriptions or locations.
-viridae
78
The suffix of animal viruses families that contains numerous genera. Often prefix is the name of the disease.
-virus
79
The _____ virus group mechanism of transmission is the fecal-oral route. Common viruses include enterovirus (polio, coxsackie B); noroviruses; rotaviruses (diarrhea).
Enteric
80
The _____ virus group mechanism of transmission is the respiratory or salivary route. Common viruses include influenza; measles; rhinoviruses (colds).
Respiratory
81
The _____ virus group mechanism of transmission is via to animal to human directly. Common viruses include rabies; cowpox.
Zoonotic
82
The _____ virus group mechanism of transmission is via Vectors (arthropods), not to be confused with zoonotic groups. Common viruses include sandfly fever, dengue fever; West Nile encephalitis; La Crosse encephalitis, yellow fever.
Arboviruses
83
The _____ transmitted virus group mechanism of transmission is via sexual contact.
Common viruses transmitted are Herpes simplex virus type 2 (genital herpes); HIV
Sexual Transmitted
84
The _____ phage(s) lyses host cell to exist at end of the infection cycle. Infections result in the formation of new viral particles, productive infections.
Lytic Phages (or, Virulent Phages)
85
The _____ infections result in the formation of new particles.
Productive Infections
86
The _____ phage that is most extensively studied. Receptors are located on the cell wall. Burst-Size is about 200.
T4 phages
87
The T4 _____ enzyme is located on the T4 Phages tip of the tail. It is used to degrade a small portion of peptidoglycan of host cell wall.
T4 Lysozyme
88
Plant viruses can be transmitted through _____ contaminated by the prior growth of infected plants, and by growers themselves.
soil
89
A _____ percentage of the known plant viruses are transmitted through contaminated seeds, tubers, or pollen.
small
90
Viruses can also spread through ______ of healthy plant tissue onto diseased plants. Tobacco mosaic virus is transmitted- ted to healthy seedlings on the hands of workers who have been in contact with the virus from infected plants.
grafting
91
The most important transmitters of plant viruses are probably \_\_\_\_\_\_; thus, insect control is a critical tool for preventing the spread of plant viruses.
insects
92
Viruses are considered as _____ \_\_\_\_\_, they do not fit the definition of life and thus are not organisms. In essence, viruses straddle the definition of life.
Infectious Agents
93
A virus contains only _____ single types of nucleic acids, the genome may be linear or circular, either double-stranded or single-stranded. Often termed as DNA viruses or RNA viruses.
One
94
The _____ microscope is used to see most viruses, minus the Mimivirus or Pandoraviruses as examples, which can be seen using a light microscope.
Electron Microscope
95
\_\_\_\_\_\_\_ are ssRNA molecules that forms a closed ring, one-tenth the size of the smallest infectious viral RNA genome known.
Viroids
96
\_\_\_\_\_ are Infectious agents composed solely of protein. They are linked to a number of slow, always fetal, human diseases. These proteins accumulate in neural tissue for unknown reasons, neurons die and brain function deteriorates as the tissue develops characteristics of holes, sponge-like appearance.
Prions
97
All _____ diseases cause transmissible spongiform encephalopathies.
All prion diseases.
98
The _____ is the normal cellular prion protein. Easily destroyed by host cell proteases.
PrPc
| (prion protein cellular)
99
The _____ is the infectious form of the prion, the shape influences stability. It is less susceptible to degradation by proteases and becomes insoluble, leading to aggregation. Not resistant to heat and chemical treatments for inactivating infectious agents.
PrPsc
| (prion protein, scrapie)
100
The _____ is a prion disease with the host of sheep and goats. No human deaths associated.
Scrapie
101
The _____ is the prion diseases with the host of cattle.
BSE (Bovine Spongiform Encephalopathy, mad cow disease)
102
Prion diseases with the host of deer and elk. No human deaths associated. This diseases spread from Colorado to wild deer populations, captive farmed animals located in states and Canada. Spread through direct animal to animal (nose to nose) contact.
CWD (Chronic Wasting Disease)
103
The _____ is the prion diseases with the host of ranched mink.
TME (Transmissible Mink Encephalopathy)
104
The _____ is the prion diseases with the host of Antelope in South Africa.
EUE (Exotic Ungulate Encephalopathy)
105
The _____ is the prion diseases with the host of Cats
FSE (Feline Spongiform Encephalopathy)
106
The _____ is the prion diseases with the host of humans, caused by cannibalism.
Kuru
107
The _____ is the prion disease with the host of humans (caused by consumption of prion-contaminated beef). Similar to mad cow disease. People ate infected tissue.
VCJD
| (Variant Creutzfeldt-Jacob Disease)
108
Prion _____ inherited diseases such as Creutzfeldt-Jakb Disease, Gerstmann-straussler-scheinker syndrome and fatal familial insomnia.
Humans (inherited)
109
All known viroids infect only plants, where they cause serious diseases, including potato spindle tuber, chrysanthemum stunt, citrus oxcarts, cucumber pale fruit, hopstunt, and cadang-cadang. Like plant viruses, they enter plants through _____ sites rather than binding to specific receptors.
wound
110
The _____ is a disease caused by a lethal viroid. Killed all but 100/250M palms in the Philippines by 1962. Today this affects the production of copra, the raw material for coconut oil and animal feed. It affects the;
## Footnote
* coconut,
* Anahow,
* Buri
* African Palm Oil.
CCCVd (Cadang-cadang)
111
A type of antigenic variation called Antigenic _____ occurs as a mutation accumulates in genes encoding key viral surface proteins that are recognized by the immune system. The immune response may work one year but not for the variant that circulates the next year.
Antigenic Drift
112
Antigenic _____ is where virus with a segmented genome that undergoes reassortment, when a new subtype of the virus is formed by reassortment between different strains of a virus, or even between different viruses, this is what the phenomena is called.
Antigenic Shift
113
\_\_\_\_\_ is where viruses trigger a normal cellular process, also referred to as programmed cell death prior to the release of the viral particles.
Apoptosis
| (or programmed cell death)
114
Influenza viruses, for example, exhibit a type of antigenic variation called _____ \_\_\_\_\_. Because of this, a person immune response from one year may not protect against the influenza virus the next year.
antigenic drift
115
