Microbiology Exam 2 Questions and
answers
Are Viruses Living or Nonliving? - correct answer-They are only considered living when they
are inside of a host cell, using their resources and energy.
Outside of a host they are considered inert.
When are Viruses considered to be "alive"? - correct answer-When they are inside of a host
cell.
When inside, their nucleic acid (ONLY RNA OR DNA) become active.
*Virus replicates
Obligatory Intracellular Parasites - correct answer-Require livinghost cell in order to multiply -
Such as Viruses.
Defining a Virus - correct answer-1) Contains 1 Nucleic Acid (DNA or RNA)
2) Protein coat surrounds the DNA or RNA
3)Multiply within host using host machinery
---because they don't have the ways of making/obtaining their own nutrients. like ATP or
enzymes.
Virus Characteristics - correct answer-*Some are enclosed by an envelope which consists of
lipids, proteins, carbohydrates
*some have spikes
*only infect the cells of ONE host.
Host Range - correct answer-The spectrum of host cells that a virus can infect.
-invertebrates
-vertebrates
-plants
-protist
-fungi
-bacteria
The virus must be able to attach to a the particular host's cell.
**Host range is determined b specific attachment sites on the host cell's surface
Bacteriophages - correct answer-Bacteria that is infected by a virus
,How do Viruses attach to a host cell - correct answer-Through receptors on the host cell's
surface.
There must be an interaction.
Capsid - correct answer-Protein coat that surrounds the Nucleic Acid of a virus. (not the
whole virus itself. That's an envelope.)
****Made up of individualized Capsomeres****
*accounts for most of the mass of a viral cell.
Capsomeres - correct answer-Protein subunits that make up a capsid
(think of tiny balls that come together to make a huge coating around the Nucleic Acid)
*capsomeres can be made up of multiple types of proteins or one single type of protein
Envelope - correct answer-Surrounds the virus as a whole.
*Synonymus to a somatic cell's Plasma Membrane. But around a virus.
***Composed of proteins, lipids and carbs.
*Could be covered in spikes
NOT ALL VIRUSES HAVE ENVELOPES
Spikes - correct answer-Cover the envelope of the cell
Composed of protein and carbohydrates.
-Used for attachment to the host cell
Spikes differ, and can be identified as different virus by the host body. That's why you can
get the flu more than once a year, there's a change in spikes.
-Can be used for identification for some virsus under microscope.
Helical Capsid - correct answer-Long rods that are flexible and rigid
These surround the Nucleic Acid.
*Capsids are hollow cylinders surrounding the nucleic acid.
*CAN OR CANNOT HAVE A ENVELOPE.
Without envelope = they look like long noodles, because it's just the capsid and no
sphereical shape
WITH the envelope = they look like balls, but with their Nucleic acids all tangled inside.
, Polyhedrical Capsid - correct answer-These are icosahedron, and are 20 triangle shapes,
with 12 corners.
THEY CAN BE WITH OR WITHOUT ENVELOPE
-Without envelope, you can see their individual caposomere and their many different
triangular faces of the Capsid
WITH envelope, they appear ordinarily spherical, and like a normal cell. (Some have spikes)
Complex Capsid - correct answer-They have a variety of weird shapes within the one virus
cell, and look just straight up weird.
They can be bacteriaphages and just look mutuant
Family names suffix for Taxonomy - correct answer--viridae
Ex. Herpesviridae
Genus name suffix Taxonomy - correct answer--virus
Genus Simplexvirus
Ex. Herpesvirus
Viral species - correct answer-A group of viruses sharing the same genetic information and
ecological niche (niche=host)
Viral species are designated by descriptive common names, such as human
immunodeficiency virus (HIV),
Subspecies - correct answer-They are determined by the NUMBER that is attached to the
specific genus of the family. These are viruses that can affect humans
HIV-1, HIV-2
Plaque - correct answer-Areas of clearing where the the virus has killed the bacteria
PFU - correct answer-Plaque Forming Unit
*Concentrations of viral suspensions measured by the number of plaques
Cytopathic Effect - correct answer-CPE
This is cell deterioration after a virus infects a monolayer of cells that appears to be growing
just fine.
The cells clump together as they deteriorate.
answers
Are Viruses Living or Nonliving? - correct answer-They are only considered living when they
are inside of a host cell, using their resources and energy.
Outside of a host they are considered inert.
When are Viruses considered to be "alive"? - correct answer-When they are inside of a host
cell.
When inside, their nucleic acid (ONLY RNA OR DNA) become active.
*Virus replicates
Obligatory Intracellular Parasites - correct answer-Require livinghost cell in order to multiply -
Such as Viruses.
Defining a Virus - correct answer-1) Contains 1 Nucleic Acid (DNA or RNA)
2) Protein coat surrounds the DNA or RNA
3)Multiply within host using host machinery
---because they don't have the ways of making/obtaining their own nutrients. like ATP or
enzymes.
Virus Characteristics - correct answer-*Some are enclosed by an envelope which consists of
lipids, proteins, carbohydrates
*some have spikes
*only infect the cells of ONE host.
Host Range - correct answer-The spectrum of host cells that a virus can infect.
-invertebrates
-vertebrates
-plants
-protist
-fungi
-bacteria
The virus must be able to attach to a the particular host's cell.
**Host range is determined b specific attachment sites on the host cell's surface
Bacteriophages - correct answer-Bacteria that is infected by a virus
,How do Viruses attach to a host cell - correct answer-Through receptors on the host cell's
surface.
There must be an interaction.
Capsid - correct answer-Protein coat that surrounds the Nucleic Acid of a virus. (not the
whole virus itself. That's an envelope.)
****Made up of individualized Capsomeres****
*accounts for most of the mass of a viral cell.
Capsomeres - correct answer-Protein subunits that make up a capsid
(think of tiny balls that come together to make a huge coating around the Nucleic Acid)
*capsomeres can be made up of multiple types of proteins or one single type of protein
Envelope - correct answer-Surrounds the virus as a whole.
*Synonymus to a somatic cell's Plasma Membrane. But around a virus.
***Composed of proteins, lipids and carbs.
*Could be covered in spikes
NOT ALL VIRUSES HAVE ENVELOPES
Spikes - correct answer-Cover the envelope of the cell
Composed of protein and carbohydrates.
-Used for attachment to the host cell
Spikes differ, and can be identified as different virus by the host body. That's why you can
get the flu more than once a year, there's a change in spikes.
-Can be used for identification for some virsus under microscope.
Helical Capsid - correct answer-Long rods that are flexible and rigid
These surround the Nucleic Acid.
*Capsids are hollow cylinders surrounding the nucleic acid.
*CAN OR CANNOT HAVE A ENVELOPE.
Without envelope = they look like long noodles, because it's just the capsid and no
sphereical shape
WITH the envelope = they look like balls, but with their Nucleic acids all tangled inside.
, Polyhedrical Capsid - correct answer-These are icosahedron, and are 20 triangle shapes,
with 12 corners.
THEY CAN BE WITH OR WITHOUT ENVELOPE
-Without envelope, you can see their individual caposomere and their many different
triangular faces of the Capsid
WITH envelope, they appear ordinarily spherical, and like a normal cell. (Some have spikes)
Complex Capsid - correct answer-They have a variety of weird shapes within the one virus
cell, and look just straight up weird.
They can be bacteriaphages and just look mutuant
Family names suffix for Taxonomy - correct answer--viridae
Ex. Herpesviridae
Genus name suffix Taxonomy - correct answer--virus
Genus Simplexvirus
Ex. Herpesvirus
Viral species - correct answer-A group of viruses sharing the same genetic information and
ecological niche (niche=host)
Viral species are designated by descriptive common names, such as human
immunodeficiency virus (HIV),
Subspecies - correct answer-They are determined by the NUMBER that is attached to the
specific genus of the family. These are viruses that can affect humans
HIV-1, HIV-2
Plaque - correct answer-Areas of clearing where the the virus has killed the bacteria
PFU - correct answer-Plaque Forming Unit
*Concentrations of viral suspensions measured by the number of plaques
Cytopathic Effect - correct answer-CPE
This is cell deterioration after a virus infects a monolayer of cells that appears to be growing
just fine.
The cells clump together as they deteriorate.
