MICB 212 PREPARATION TEST 2026
QUESTIONS AND CORRECT ANSWERS
GRADED A+
● Describe the structure of a virus and how they infect host cell
mechanism? Answer: Viruses exist in either an extracellular or an
intracellular form. The extracellular form of the virus is known as a virus
particle or virion. The extracellular form of the virus particle serves to
transfer the viral genome from one cell to another.
In order to replicate, the virus particle bind to a host cell and the genome
(and any needed proteins) must enter a cell. A cell that supports the virus
replication cycle of a virus is called a host cell. When the viral genome
is introduced into a host cell and replicated, the process is called an
infection.
In the intracellular state, viruses exist primarily as replicating nucleic
acids. They use the host cell to provide energy, enzymes, metabolic
components (e.g., amino acids), and structural machinery (e.g.,
ribosomes) to replicate the genome and synthesize the viral proteins that
make up the virus coat. Once the virus particles have been assembled
they are eventually released from the host cell
● What protective layers do viral genomes have? Answer: All viruses
have their nucleic acid genome covered by a protective capsid. The
proteins of the capsid are encoded in the viral genome. The individual
, protein subunit is called a capsomere; multiple copies of the capsomere
proteins assemble to form the capsid. The capsids can be described as
being helical, icosahedral (sometimes referred to as spherical) or
complex in morphology. Some viruses also have an additional layer
consisting of a lipid bilayer (called the envelope) (see Figure 1.3). Some
viruses also have enzymes needed for the replication of their genomes
packaged inside the capsid.
● What are some of the functions of the protein coat that surrounds the
genome of a naked virus particle? Answer: A. Helical capsids
In helical capsids, the capsid protein has affinity for the viral genome
and for other copies of the capsid protein. It assembles by attaching to
the virus genome as the genome is being synthesized. The length of the
helical capsid is as long as the genome itself.
B. Icosahedral capsids
One way to construct a symmetrical capsid with maximal internal
volume with non-symmetric protein molecules is to arrange the protein
molecules in identical equilateral triangular structures that can be joined
to form icosahedrons. Icosahedrons are structures formed by 20
equilateral triangles: 5 at the top, 5 at the bottom and 10 in the middle.
Depending of the specific example, the triangular faces can be made of
QUESTIONS AND CORRECT ANSWERS
GRADED A+
● Describe the structure of a virus and how they infect host cell
mechanism? Answer: Viruses exist in either an extracellular or an
intracellular form. The extracellular form of the virus is known as a virus
particle or virion. The extracellular form of the virus particle serves to
transfer the viral genome from one cell to another.
In order to replicate, the virus particle bind to a host cell and the genome
(and any needed proteins) must enter a cell. A cell that supports the virus
replication cycle of a virus is called a host cell. When the viral genome
is introduced into a host cell and replicated, the process is called an
infection.
In the intracellular state, viruses exist primarily as replicating nucleic
acids. They use the host cell to provide energy, enzymes, metabolic
components (e.g., amino acids), and structural machinery (e.g.,
ribosomes) to replicate the genome and synthesize the viral proteins that
make up the virus coat. Once the virus particles have been assembled
they are eventually released from the host cell
● What protective layers do viral genomes have? Answer: All viruses
have their nucleic acid genome covered by a protective capsid. The
proteins of the capsid are encoded in the viral genome. The individual
, protein subunit is called a capsomere; multiple copies of the capsomere
proteins assemble to form the capsid. The capsids can be described as
being helical, icosahedral (sometimes referred to as spherical) or
complex in morphology. Some viruses also have an additional layer
consisting of a lipid bilayer (called the envelope) (see Figure 1.3). Some
viruses also have enzymes needed for the replication of their genomes
packaged inside the capsid.
● What are some of the functions of the protein coat that surrounds the
genome of a naked virus particle? Answer: A. Helical capsids
In helical capsids, the capsid protein has affinity for the viral genome
and for other copies of the capsid protein. It assembles by attaching to
the virus genome as the genome is being synthesized. The length of the
helical capsid is as long as the genome itself.
B. Icosahedral capsids
One way to construct a symmetrical capsid with maximal internal
volume with non-symmetric protein molecules is to arrange the protein
molecules in identical equilateral triangular structures that can be joined
to form icosahedrons. Icosahedrons are structures formed by 20
equilateral triangles: 5 at the top, 5 at the bottom and 10 in the middle.
Depending of the specific example, the triangular faces can be made of
