MIC 319 EXAM 2 QUESTIONS WITH 100%
CORRECT ANSWERS
Class 1 - ANSWER Knowing the enemy: Virology
What makes a virus unique? - ANSWER they are infectious, obligate intracellular
parasites (cannot replicate on their own, they need a host)
- the way it infects (receptor to infect)
- it needs conducive environment (to replicate)
- its genetic makeup
What percentage of human DNA comes from viruses? - ANSWER 8% of human DNA
comes from viruses
Why don't viruses we eat infect us? - ANSWER - they are dead (usually get cooked and
die)
- we do not have a receptor for them (Tropism = every virus has a special molecule on
their surface for infection) plant viruses cannot infect animals and vice versa
- we have no survival habitat
What information do we get from physical measurement of virus particles? - ANSWER -
the number of virus particles
- the shape of the virus
- the size of the virus
- hemagglutination
- viral enzymes
- electron microscopy
- nucleic acids
- serology
does *NOT* give infectivity (alive or dead) of virus
What happens when we eat plant viruses? - ANSWER Nothing
How many classes of viruses are there? - ANSWER there are 7 classes of viruses based
on their nucleic acid and strandedness
, - dsDNA
- gapped dsDNA
- SSDNA
- dsRNA
- SS (+) RNA
- SS (-) RNA
- SS (+) RNA with DNA intermediate
What are the biggest and smallest viruses? - ANSWER Smaller viruses can be around 20
micrometers
- example: poliovirus (30 nm)
Larger viruses can be around 1 um
- example: mimivirus and pandora virus
How many basic types of viral shapes? - ANSWER there are 3 basic types of viral
shapes:
- helical
- icosahedral
- complex
Who classified viruses and what are the classifications? - ANSWER - David Baltimore
created "The Baltimore System" to classify viruses
- the goal of all virus forms: produce +mRNA (made by translation)
- places viruses into one of seven groups depending on a combination of their nucleic
acid (DNA or RNA), strandedness (single-stranded or double-stranded)
Infectious cycle of viruses: - ANSWER 1. Attachment and entry
2. Translation
3. Genome replication
4. Assembly
5. Release
How can you tell how many viral particles are in a sample? - ANSWER - *Infectivity*
(Plaque assay: Dilution of virus stock/One-hit and two-hit kinetics)
CORRECT ANSWERS
Class 1 - ANSWER Knowing the enemy: Virology
What makes a virus unique? - ANSWER they are infectious, obligate intracellular
parasites (cannot replicate on their own, they need a host)
- the way it infects (receptor to infect)
- it needs conducive environment (to replicate)
- its genetic makeup
What percentage of human DNA comes from viruses? - ANSWER 8% of human DNA
comes from viruses
Why don't viruses we eat infect us? - ANSWER - they are dead (usually get cooked and
die)
- we do not have a receptor for them (Tropism = every virus has a special molecule on
their surface for infection) plant viruses cannot infect animals and vice versa
- we have no survival habitat
What information do we get from physical measurement of virus particles? - ANSWER -
the number of virus particles
- the shape of the virus
- the size of the virus
- hemagglutination
- viral enzymes
- electron microscopy
- nucleic acids
- serology
does *NOT* give infectivity (alive or dead) of virus
What happens when we eat plant viruses? - ANSWER Nothing
How many classes of viruses are there? - ANSWER there are 7 classes of viruses based
on their nucleic acid and strandedness
, - dsDNA
- gapped dsDNA
- SSDNA
- dsRNA
- SS (+) RNA
- SS (-) RNA
- SS (+) RNA with DNA intermediate
What are the biggest and smallest viruses? - ANSWER Smaller viruses can be around 20
micrometers
- example: poliovirus (30 nm)
Larger viruses can be around 1 um
- example: mimivirus and pandora virus
How many basic types of viral shapes? - ANSWER there are 3 basic types of viral
shapes:
- helical
- icosahedral
- complex
Who classified viruses and what are the classifications? - ANSWER - David Baltimore
created "The Baltimore System" to classify viruses
- the goal of all virus forms: produce +mRNA (made by translation)
- places viruses into one of seven groups depending on a combination of their nucleic
acid (DNA or RNA), strandedness (single-stranded or double-stranded)
Infectious cycle of viruses: - ANSWER 1. Attachment and entry
2. Translation
3. Genome replication
4. Assembly
5. Release
How can you tell how many viral particles are in a sample? - ANSWER - *Infectivity*
(Plaque assay: Dilution of virus stock/One-hit and two-hit kinetics)
