Viruses Flashcards
All viruses are obligate ______ _____ meaning they must be inside a host cell to replicate
Intracellular parasites
Viruses can infect all types of ___ life including bacteria, fungi, etc.
Cellular
in general, all viruses have the basic structure of ___ ____ surrounded by a potential
Nucleic acid
In general, all viruses are _____ in size
Ultramicroscopic
All viruses have a defined ___ ____ of cell types that can support the viral lifecycle. Each species has a range aka ____. They also have a certain range of cells they can infect.
Host range
Tropism
All viruses replicate in a ___ ___ fashion, rather than by binary fission
Step-wise
In 1892, there was evidence of non-bacterial ___ ___, sadly ivanosky himself was convinced he had discovered an inculturable bacterium.
Infectious agent
___ ___ filter was used to purify water using porsaline. This was used by Ivanosvky to study diseased ____ leaves and look for microbes. He discovered that it was something much ___ that was able to pass through the filter
Pasteur-chamberland
Tobacco
Smaller
In 1898, beijerinck repeated the experiment and realized it was not cellular life and coined the term ____.
Virus
In 1902, ___ ___ was the first human virus discovered. From a mosquito bite
Yellow fever
Example of a step 1 question:
Classic influenza presentation with pneumonia.
An envelope double stranded DNA virus example:
Herpes
An envelope non-segmented, single-stranded RNA virus example:
Hepatitis C
An enveloped segmented, single stranded RNA virus example:
Influenza
Non-envelope non-segmented, single-stranded RNA virus example:
Polio
Non-envelope segmented, double-stranded RNA virus example:
Roda virus
Diagram of sizes of virus:
Mimivirus is newly discovered and is getting closer to the size of bacteria
All viruses have a genome made of Nucleic acids that is packaged in a _____. If that’s all we refer to them as a ____ virus. The ______ is the Nucleic acid plus the capsid.
Capsin
Naked
Nucleocapsid
The space between the capsid and the envelope that is full of proteins and RNA, is referred to as the _____
Tegument
Enveloped viruses are more complex and have ____ proteins on their surface
Spiked
Two types of nucleocapsids:
1. ____: genome is boxed in
2. ____: the Nucleocapsid proteins themselves bind directly to the Nucleic acids and the RNA/DNA can coil
Icosahedral
Helical
Poliovirus is a ___ virus. Picture of the capsid
Naked
The herpes virus is an ___ virus. Picture:
Enveloped
Red center is double stranded DNA surrounded by green capsid. Purple layer is RNA and excessory proteins. Orange layer is the envelope. Yellow is glycoproteins or spike proteins
Herpes virus capsid if you strip everything else away except for the capsid:
Coronavirus:
Genome is RNA. RNA has protein stuck right to it meaning ____. It is ___ with spike proteins.
Helical
Enveloped
Influenza:
Is single stranded RNA. There is protein bound right to the surface of the RNA making it ___ Nucleocapsid. The genome is ____. It is enveloped with spike proteins.
Helical
Segmented
Influenza can undergo ____ because it’s genome is segmented.
___ ___ occurs when major changes in antigens occur due to Gene reassortment
___ ____ occurs when a minor changes in antigens occur due to gene mutation
Reassortment
Antigenic shift
Antigenic drift
Two different types of virus particle can be infecting the ___ cell at the ___ time and undergoes reassortment.
Same
Same
___ ___ is due to random mutations. There is no _____ mechanism in viruses. They are constantly changing. New flu vaccine every year.
Antigenic drift
Proofreading
Bacteriophage structure:
Naked, helical, etc, similar to human viruses. But they also have ___ that help them penetrate bacterial cell wall.
Tails
The ____ classification system have seven different categories based on the seven different ways that viruses replicate
Baltimore
Baltimore classification:
First, Looking at single versus double stranded ___ or ___.
DNA RNA
+ sense RNA is identical to ____ RNA
Messenger
-sense RNA means the virus first has to ____ in order for it to be used as mRNA.
+ sense RNA is already mRNA.
Transcribe
Class I and class VII:
Double stranded DNA + sense virus
Class II:
Single-stranded DNA + sense virus
Class III:
Double-stranded RNA + sense virus
Class IV:
Single-stranded RNA + sense virus
Class V:
Single-stranded RNA - sense virus
Class VI:
Single-stranded RNA + sense retrovirus
Review:
+ sense RNA gets copied into ____ RNA
-sense
General viral replication cycle:
_____ are packaged nucleic acids that get released via lysis
Virions
In general, viruses with an RNA genome complete replication in the ____. They do not need to gain excess to the host cell nucleus.
Cytoplasm
In general, viruses with a DNA genome will use the host cell ____.
Nucleus
Class I example:
Class II example:
One-step growth is not exponential growth. Once the virus penetrates there is an ____ period where there is no infectious virus found in the cell at that time because the virus broke itself down. This is a ____ period
Eclipse
Latent
In one-step you go from having one virus to ____ of viruses being shot out at once.
Hundreds
Viral quantification via the ___ ___. It is analogous to the bacterial colony. Plaques are clear zones that develops on lawns of host cells. Each plaque results from infection by a ____ virus particle .
___ is the number of infectious units per volume of fluid
Plaque assay
Single
Titer
_____ ____ of suitable host cells for the virus to infect of the Petri dish. Then you take diluted virus and wash it over the plate. Each spot represents a ____ virus particle
Confluent monolayer
Single
A plaque is formed by a virus particle ___ and ____ the host cell
Infecting
Killing
Effects that animal viruses can have on cells:
1. Transformation into a ___ ___
2. ___ ___ for a long period of time before the cell dies
3. _____ infection where the virus hides and does not replicate
Tumor cell
Persistent infection
Latent
____ viruses cause life long infection and become latent
Herpes
Bacteriophage lysis and lytic pathway:
Class I pathway to translation and genome replication:
Class II pathway:
Class III pathway:
Class IV pathway:
Class V pathways:
Class VI pathway:
Class VII pathway:
