ASU MIC 205 Final Exam verified rationales
ASU MIC 205 Final Exam verified rationales
Viruses:
-Miniscule, acellular infectious agents carrying one or several pieces of either DNA or
RNA
-Viruses are obligate intracellular parasites
-
-infect bacteria, plants, and animals; include viruses that lead to most major diseases of humans.
-NO CYTOPLASMIC membrane, cytosol, or organelles
-cant carry out metabolic reacitons
-neither grow in size nor respond to their environment
-cant reproduce independently Structure of
Viruses:
-when outside of their hosts- they are called -virions
-A virion has a protein coat called a capsid that surrounds and protects the nucleic acid called
a viral genome and sometimes provides means for attachment to host cells -some virions will
possess additional features such as
-enzymes they need to complete their life cycle
-glycoprotein appendages for attachment to host cells
-envelope that is composed of a phospholipid bilayer (helps them be undetectable by cells) -
when inside the cellular hosts, viruses
-shed their protein capsids and inject their nucleic acid into the host cell
The Viral Envelope:
-some but not all animal viruses have envelopes
-the envelope is composed of a phospholipid bilayer and proteins
-some proteins are glycoprotein spikes that are encoded by the viral genome
-envelopes proteins and glycoproteins often play rolls in host cell recognition -viral
envelopes are acquired from the host cell during viral replicaiton
-enveloped animal viruses surround themselves in stolen membrane material that
looks like a host cell so it isn’t recognized
Like viruses surround themselves in phospholipid bilayer membrane- why not do that for autoimmune
diseases so that they aren’t recognized and won’t be attacked by antibodies?
,ASU MIC 205 Final Exam verified rationales
Hosts of Viruses:
-most infect particular kinds of host cells
-due to a lot of different surface proteins or glycoproteins for complementary proteins or
glycoproteins on the host cell surface they choose the easiest ones
-may only infect a particular kind of cell or one host.
-(narrow host range)
-some are generalists that infect many kinds of cells in many different hosts (rare)
How are viruses categorized
-they are categorized by the type of genetic material they contain
-may be DNA or RNA but never both
-may be single or double stranded DNA or RNA
-may be multiple linear fragments or a single circular molecule -much much
smaller than cellular genomes
-they can also be categorized by the kinds of cells they infect
-size and shape of virus
-structure of protein coat (capsid)
-presence or absence of an envelope
, Viral réplication:
-dependent on host cells organelles and enzymes to produce new virions (virus particles) -virus gets
inside, splits the cell in half and releases virions
-Types of replication mechanisms:
-lytic replication- destructive mechanism that results in death and degradation (lysis) of
the host cell
-lysogenic replication: an extended period of dormancy initiated by certain bacteriophages
-latent replication: temporary or permanent dormancy elicited by certain types of animal viruses
-difference between lysogenic and latent is the type of virus
Lytic replication:
1. Attachment
2.entry- genetic material gets shoved into cell
3.synthesis- transcription and translation of the genes of host cell.
4.assembly- all of the proteins of virus come together, packaging of new genetic material
5.release- lysis of the cell and the virion are released
Burst time- period of time required to complete the entire lytic process, from attachment to release
Burst size- total number of new virions released from a given population of lysed bacterial cells
ASU MIC 205 Final Exam verified rationales
Viruses:
-Miniscule, acellular infectious agents carrying one or several pieces of either DNA or
RNA
-Viruses are obligate intracellular parasites
-
-infect bacteria, plants, and animals; include viruses that lead to most major diseases of humans.
-NO CYTOPLASMIC membrane, cytosol, or organelles
-cant carry out metabolic reacitons
-neither grow in size nor respond to their environment
-cant reproduce independently Structure of
Viruses:
-when outside of their hosts- they are called -virions
-A virion has a protein coat called a capsid that surrounds and protects the nucleic acid called
a viral genome and sometimes provides means for attachment to host cells -some virions will
possess additional features such as
-enzymes they need to complete their life cycle
-glycoprotein appendages for attachment to host cells
-envelope that is composed of a phospholipid bilayer (helps them be undetectable by cells) -
when inside the cellular hosts, viruses
-shed their protein capsids and inject their nucleic acid into the host cell
The Viral Envelope:
-some but not all animal viruses have envelopes
-the envelope is composed of a phospholipid bilayer and proteins
-some proteins are glycoprotein spikes that are encoded by the viral genome
-envelopes proteins and glycoproteins often play rolls in host cell recognition -viral
envelopes are acquired from the host cell during viral replicaiton
-enveloped animal viruses surround themselves in stolen membrane material that
looks like a host cell so it isn’t recognized
Like viruses surround themselves in phospholipid bilayer membrane- why not do that for autoimmune
diseases so that they aren’t recognized and won’t be attacked by antibodies?
,ASU MIC 205 Final Exam verified rationales
Hosts of Viruses:
-most infect particular kinds of host cells
-due to a lot of different surface proteins or glycoproteins for complementary proteins or
glycoproteins on the host cell surface they choose the easiest ones
-may only infect a particular kind of cell or one host.
-(narrow host range)
-some are generalists that infect many kinds of cells in many different hosts (rare)
How are viruses categorized
-they are categorized by the type of genetic material they contain
-may be DNA or RNA but never both
-may be single or double stranded DNA or RNA
-may be multiple linear fragments or a single circular molecule -much much
smaller than cellular genomes
-they can also be categorized by the kinds of cells they infect
-size and shape of virus
-structure of protein coat (capsid)
-presence or absence of an envelope
, Viral réplication:
-dependent on host cells organelles and enzymes to produce new virions (virus particles) -virus gets
inside, splits the cell in half and releases virions
-Types of replication mechanisms:
-lytic replication- destructive mechanism that results in death and degradation (lysis) of
the host cell
-lysogenic replication: an extended period of dormancy initiated by certain bacteriophages
-latent replication: temporary or permanent dormancy elicited by certain types of animal viruses
-difference between lysogenic and latent is the type of virus
Lytic replication:
1. Attachment
2.entry- genetic material gets shoved into cell
3.synthesis- transcription and translation of the genes of host cell.
4.assembly- all of the proteins of virus come together, packaging of new genetic material
5.release- lysis of the cell and the virion are released
Burst time- period of time required to complete the entire lytic process, from attachment to release
Burst size- total number of new virions released from a given population of lysed bacterial cells
