MICROBIOLOGY EXAM 2 WITH 155
QUESTIONS AND CORRECT ANSWERS
RATED A+ 2026/2027
Capsomeres
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
Are Viruses Living or Nonliving?
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 intert.
When are Viruses considered to be "alive"?
When they are inside of a host cell.
When inside, their nucleic acid (ONLY RNA OR DNA) become active.
*Virus replicates
Obligatory Intracellular Parasites
Require livinghost cell in order to multiply - Such as Viruses.
Defining a Virus
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
*Some are enclosed by an envelope which consists of lipids, proteins,
carbohydrates
*some have spikes
*only infect the cells of ONE host.
Envelope
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
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
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
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)
Subspecies
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
Areas of clearing where the the virus has killed the bacteria
PFU
Plaque Forming Unit
*Concentrations of viral suspensions measured by the number of plaques
Cytopathic Effect
, 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.
Virion
Complete, fully developed, infectious viral particle composed of nucleic acid and
surrounded by protein coat that protects it from the environment and is a vehicle
of transmission from one host cell to another.
**AKA MATURE PHAGE
Lytic Cycle
The cycle that bacteriophages use to multiply.
WHERE THE CYCLE ENDS WITH LYIS AND DEATH OF HOST CELL.
Lysogenic Cycle
The cycle that bacteriophages use to multiply.
Where the host cell remails alive after the cycle.
Phage Lysozyme
Enzyme released by the bacteriophage tails to break down bacteria cell wall so
they can enter the bacteria.
Lytic Cycle of a T-Even Bacteriophage
1) ATTACHMENT to bacteria cell wall by tail fibers to complementary receptor
sites
2) ENTRY of viron DNA inside the bacteria, and the protein capsid is left outside of
the bacteria cell
QUESTIONS AND CORRECT ANSWERS
RATED A+ 2026/2027
Capsomeres
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
Are Viruses Living or Nonliving?
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 intert.
When are Viruses considered to be "alive"?
When they are inside of a host cell.
When inside, their nucleic acid (ONLY RNA OR DNA) become active.
*Virus replicates
Obligatory Intracellular Parasites
Require livinghost cell in order to multiply - Such as Viruses.
Defining a Virus
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
*Some are enclosed by an envelope which consists of lipids, proteins,
carbohydrates
*some have spikes
*only infect the cells of ONE host.
Envelope
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
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
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
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)
Subspecies
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
Areas of clearing where the the virus has killed the bacteria
PFU
Plaque Forming Unit
*Concentrations of viral suspensions measured by the number of plaques
Cytopathic Effect
, 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.
Virion
Complete, fully developed, infectious viral particle composed of nucleic acid and
surrounded by protein coat that protects it from the environment and is a vehicle
of transmission from one host cell to another.
**AKA MATURE PHAGE
Lytic Cycle
The cycle that bacteriophages use to multiply.
WHERE THE CYCLE ENDS WITH LYIS AND DEATH OF HOST CELL.
Lysogenic Cycle
The cycle that bacteriophages use to multiply.
Where the host cell remails alive after the cycle.
Phage Lysozyme
Enzyme released by the bacteriophage tails to break down bacteria cell wall so
they can enter the bacteria.
Lytic Cycle of a T-Even Bacteriophage
1) ATTACHMENT to bacteria cell wall by tail fibers to complementary receptor
sites
2) ENTRY of viron DNA inside the bacteria, and the protein capsid is left outside of
the bacteria cell
