Unit 3 - Viruses Flashcards
(109 cards)
1
Q
phage means what?
A
virus
2
Q
Viruses can have DNA or ____?
A
RNA
3
Q
Do viruses benefit the host cell?
A
No, they do not bring a benefit
4
Q
Are viruses alive?
A
No
5
Q
Where do viruses live?
A
Viruses live in cells, but are not cells
6
Q
individual viruses are called what?
A
virions or particles
7
Q
all viral genomes have some covering called what?
A
Capsid or Envelope
8
Q
Is viral DNA single or double stranded?
A
Viral DNA can be both - single or double stranded
9
Q
What’s the (+) RNA strand like?
A
mRNA
10
Q
What’s the (-) RNA strand?
A
A template for (+) RNA strand
11
Q
Pox
DNA or RNA virus?
Enveloped or nonenveloped virus?
A
Pox is an enveloped DNA virus
12
Q
Herpes
DNA or RNA virus?
Enveloped or nonenveloped virus?
Single or double stranded?
A
Herpes is an enveloped DNA virus.
Double stranded.
13
Q
Hepadma
DNA or RNA virus?
Enveloped or nonenveloped virus?
Double or single strand?
A
Hepadma is an enveloped DNA virus.
Double stranded.
14
Q
Polyoma
DNA or RNA virus?
Enveloped or nonenveloped virus?
Single or double stranded?
A
Polyoma is a non enveloped DNA virus.
Double stranded.
15
Q
Papilloma
DNA or RNA Virus?
Enveloped or nonenveloped virus?
A
Papilloma is a non enveloped DNA virus.
Double stranded.
16
Q
Adeno
DNA or RNA Virus?
Enveloped or nonenveloped virus?
A
Adeno is a non enveloped DNA virus.
Double stranded.
17
Q
Parvo
DNA or RNA Virus?
Enveloped or nonenveloped virus?
Single or double stranded?
A
Parvo is a nonenveloped DNA virus.
Single stranded. (SS)
18
Q
Negative RNA is enveloped or noneveloped?
A
Negative RNA is always enveloped.
19
Q
Can all viruses enter all cells?
A
No, viruses are specific for certain types of cells.
20
Q
Types of viral entry into the cell
A
- Fusion (enveloped)
2. Endocytosis
21
Q
What types of viruses use endocytosis to enter the cell?
A
Enveloped and nonenveloped viruses can enter a call via endocytosis, although it changes slightly.
22
Q
Process for fusion cell entry (enveloped)
A
- Virus spikes bind to the receptors on the surface of host cells
- Lipid bilayer of viral envelope fuses with the host cell membrane
- Nucleocapsid is released into the cytoplasm
23
Q
Process for endocytosis (enveloped)
A
- Viral envelope spikes bind to the receptors, tricking it to think it’s an important carbon)
- Binding to the receptor triggers receptor mediated endocytosis
- Increased acidity allows nucleocapsid to escape from the endosome and enter the cytoplasm.
24
Q
Process of bacteriophage “life cycle” via lytic pathway
A
- virus injects DNA or RNA into the cell (spider looking virus)
- replicates virus genomes
- busts out of the cell via lysis
- Viruses have then replicated and go to infect other host cells to do the same process
25
Process of bacteriophage "life cycle" via lysogenic pathway
1. virus injects DNA or RNA into the cell (spider looking virus)
2. hijacks cells DNA and replication process
3. Completes cell division and host cell keeps living
(Ticking time bomb as if anything attacks the cell, the virus resorts back to the lytic pathway where cell explodes and newly replicated viruses attack other cells)
26
What are the two types of life cycles for the bacteriophage?
1. Lytic Pathway
| 2. Lysogenic Pathway
27
Who discovered the first virus and when?
Walter Reed in 1901
28
What are two examples viruses are used for good?
1. strengthen disease resistance crops
| 2. HIV helping with cancer treatments
29
What's the theory many scientists agree with?
Millions of years ago, viruses helped form the first cell nucleus when trying to infect a bacterium.
30
Viruses consist of what?
RNA or DNA and a protein coat
31
How do virus' reproduce?
Inserting DNA into a host cell
32
Retroviruses are different from regular viruses because they:
Have RNA instead of DNA
33
Vaccines can be used to prevent viral infection by what?
Creating an immune response in the host
34
Why do some viruses seem to go away and come back, like a cold sore?
The virus has entered the lysogenic cycle
35
Why is it more difficult to create a vaccine for retroviruses?
RNA mutates more frequently than DNA
36
What happens after the virus has been taken up by the cell?
It inserts into the host DNA
37
True or False: Some viruses have single stranded RNA genomes
True
38
True or False: Viruses are living
False
39
An individual virus is called a particle or a what?
Virion
40
Which of the following is not a form of viral entry?
* Fusion of enveloped virus
* Fusion of naked virus
* Endocytosis of naked virus
* Endocytosis of enveloped virus
Fusion of naked virus
41
Poliovirus and coronavirus have a _____ genome.
+ RNA
42
What body site is typically the first to be colonized by microbes after birth?
Skin
43
True or False: Bacteria do not normally inhabit the epidermis.
True
44
True or False: Reverse Transcriptase can degrade DNA.
False
45
The colon lacks oxygen, therefore it is an ______ environment.
Apoxic
46
Mechanisms of tissue specificity in microbes include tissue tropism, specific adherence, and _________.
Biofilm formation
47
Name a body site that is normally sterile.
Heart
48
What enzyme is required by viruses to make RNA from RNA?
RNA Replicase
49
What type of template is needed to make a -RNA genome?
+ RNA
50
This is a -RNA virus with a naked capsule. What is the virus type and what's an example?
Picornaviruses.
| poliovirus, Hepatitis A, Rhinovirus
51
This is a -RNA virus that is enveloped. What is the virus type and what's an example?
Coronaviruses.
| SARS
52
In poliovirus replication, RNA replicase can create _____ and ______ RNA.
+ and -
53
This is a - strand RNA virus in animals that is enveloped. What is it and what's an example?
1. Rhabdoviruses (Rabies Virus)
2. Orthomyxoviruses (Influenza)
3. Ebola Virus
54
How does influenza bring viral proteins into host cell?
RNA replicase, RNA endonuclease, steals RNA cap from host RNA and tricks it into producing its RNA.
55
What virus types are referred to as the common cold?
Adenoviruses.
56
Upon cell entry, this virus type is in the lysosome.
Reoviruses
57
Retrovirsues bring what with them?
They bring their own mRNA
58
Retroviruses
- enveloped virus with 2 copies of RNA genome and specific enzymes for reverse transcriptase
- bring their own mRNA
- retroviruses are proviruses and can remain latent in host chromosome until they get the right signal
59
Reverse Transcriptase phases
1. Reverse transcription ( DNA - RNA)
2. Synthesis of DNA from DNA template
3. RNase H activity - degrades RNA of DNA hybrid
60
normal microbial flora is found where?
nose, throat, eyes, mouth, skin, large intestine, urinary and genital systems (urethra and vagine)
61
What determines normal flora?
ph, temperature, oxygen, water, and nutrient levels are main factors determining composition of the normal flora
62
When does colonization of microbes start?
At birth and the skin is normally the first site to be colonized.
63
mixture of organisms regularly found on surface tissues
normal microbial flora
64
Where are most microbes on the skin located?
apocrine sweat glands and hair follicles
65
What are common microbes found on the skin?
1. Streptococcus
2. Staphylococcus
3. Corynebacterium
4. Propionibacterium
66
What type of gram stained bacteria thrive in a dry environment like skin?
Gram positive bacteria
67
What type of normal flora is located in the conjuctiva (white part of eyes)?
1. Staphylococcus epidermidis
| 2. Propionibacterium acnes
68
What type of microbe usually results in dental plaque?
streptococci
69
normal flora of gastrointestinal tract
helicobacter pylon (gram negative) and can make ulcers
70
normal flora of respiratory tract
staphylococcus epidermiditis
| cornybacteria
71
True or fasle: the sinuses and lower respiratory tract should be sterile.
true
72
normal flora of urethra
staph. epidermidis
| entococcus faecalis
73
beneficial effects of normal flora according to mouse study
```
increase in vitamins
prevent pathogen colonization
increase immune system
increased natural antibodies
stimulated development of certain tissues
```
74
What are the harmful effects of normal flora?
1. bacterial synergism (cross feeding between microbes)
2. competition for nutrients (could deplete host of nutrients)
3. agents of disease (opportunistic pathogens)
75
Babies born via c-section are more likely to have what?
leukemia, asthma, and immune diseases
76
How long does it take for a newborn to develop normal microbial flora?
2 years
77
Types of bacterial pathogens
1. potential pathogens
2. opportunistic pathogens
3. obligate pathogens - will make you sick if exposed
78
mechanisms of bacterial pathogens
1. exposure to pathogens
2. adherence to skin or mucosa
3. invasion through epithelium
4. colonization and growth of virulence factors
79
3 types of toxins
1. exotoxins
2. enterotoxins
3. endotoxins
80
toxin proteins released from the pathogen cell as it grows
exotoxins
81
toxin that effects the small intestines and tells cells to release fluid into intestinal lumen, resulting in vomiting and diarrhea
enterotoxins
82
toxin that tells the lipopolysacchoride (LPS) portion of the cell wall of gram negative bacteria is a toxin
(cell bound)
endotoxins
83
True or false: exotoxins do not trigger fever or strong immune system response
True
84
toxicity and ___________ can happen at the same time but do not have to
invasiveness
85
study of the occurrence, distribution, and determinants of health and disease in a population (public health)
epidemiology
86
disease occurs in a high number of the population at the same time
epidemic
87
disease is widespread and usually worldwide
pandemic
88
when disease is constantly present but at a low incidence (plague in southwest USA)
endemic
89
the number of new cases of a disease in a population over a given time period (ex. Kentucky had 1,400 new coronaviruses cases since 4 pm yesterday)
incidence
90
total new and existing cases in a population during a given time (example: Kentucky had had a total of 94,000 coronavirus cases since March, 2020)
prevalence
91
number of cases observed in an area with previously sporadic cases
outbreak
92
person with a subclinical infection that can spread a disease
carrier
93
incidence of death in the population
mortality
94
incidence of disease in a population
morbidity
95
organism invades and grows in a host
infection
96
the time between exposure to the disease and appearance of symptoms
incubation period
97
when the disease is at its height with symptoms
acute period
98
when symptoms start to subside
decline period
99
when a patient regains strength and returns to normal after having a disease
convalescent period
100
some organisms become __________ and stay with you forever.
latent
101
Typhoid Mary was a ___________ for the typhoid fever.
Reservoir
102
when an infected person transmits a disease directly to an uninfected host without an intermediate (cold flu, STDs)
host to host
103
transmission from person to person via an intermediate
indirect host to host
104
living agents of transmission
vectors
105
non-living intermediates (surfaces, bedding, toys, etc....)
fomites
106
true or false: pathogens that live in soil or non-host environment do not typically evolve to be less virulent
True because they do not need a host to survive (cannot be virus, only bacteria)
107
True or false: some pathogens evolve into stronger infectious agents.
True
108
You cannot travel internationally and must be treated and quratine in place if you have any of the following diseases.
smallpox, cholera, plague, yellow fever, typhoid fever, relapsing fever
109
What does the public health do?
- control the reservoir (immunize or destroy animals)
(immunize or quarantine infected humans)
- control transmission
- immunization (provideas herd immunity)
- quarantine (until communicable stage is passed)
