Know the different types of viruses which have a dsRNA genome A type of infection caused by bacteriophages which involves a transition from a lytic to a lysogenic stage. What is the defense mechanism employed by the T4 phage to prevent excision of its DNA by restriction enzymes? Know the viruses that use RNA/DNA genomes. Describe in general terms how bacteriophage lambda regulates the switch between the lytic and lysogenic cycles. Proteins involved? What factors may influence the transition from a lytic to lysogenic state in lambda phage? Describe in general terms how bacteriophage lambda regulates the switch between the lytic and lysogenic cycles. Other Proteins involved? Describe in general terms the strategy used by the ssDNA virus phiX174 to synthesize its nucleic acids and proteins. Function of the replicative form? Know the different viruses which have a ssDNA genome Outline the major events involved in plus-strand RNA viruses and the specific mechanisms used to accomplish each step. Type of template used? Describe in general terms the strategy used by minus and plus strand RNA viruses to synthesize their nucleic acids and proteins. Propose how a retrovirus with a single RNA molecule as its genome might generate multiple proteins from that molecule. Intermediate molecule? What are cytokines? Roles in immunity? What is the alternate complement pathway? Roles? What are the functions and locations (blood, tissue etc) of the different immune cells? Mechanisms employed by the lungs to help protect it from infection What are dendritic cells? Roles they play in the immune response? Specific vs non-specific Function of lysozyme? Know the different body areas which act as physical barriers to infection. Know the different physical and biological defense mechanisms? Examples? Solution As per the rule i have answered your first question: Reoviridae: Reoviridae are currently classified into nine genera. The genomes of these viruses consist of 10 to 12 segments of dsRNA, each generally encoding one protein. The mature virions are non-enveloped. Their capsids, formed by multiple proteins, have icosahedral symmetry and are arranged generally in concentric layers. A distinguishing feature of the dsRNA viruses, irrespective of their family association, is their ability to carry out transcription of the dsRNA segments, under appropriate conditions, within the capsid. In all these viruses, the enzymes required for endogenous transcription are thus part of the virion structure. Orthoreoviruses: The orthoreoviruses (reoviruses) are the prototypic members of the virus Reoviridae family and representative of the turreted members, which comprise about half the genera. Like other members of the family, the reoviruses are non-enveloped and characterized by concentric capsid shells that encapsidate a segmented dsRNA genome. In particular, reovirus has eight structural proteins and ten segments of dsRNA. A series of uncoating steps and conformational changes accom.

1. Know the different types of viruses which have a dsRNA genome A type of infection caused by
bacteriophages which involves a transition from a lytic to a lysogenic stage. What is the defense
mechanism employed by the T4 phage to prevent excision of its DNA by restriction enzymes?
Know the viruses that use RNA/DNA genomes. Describe in general terms how bacteriophage
lambda regulates the switch between the lytic and lysogenic cycles. Proteins involved? What
factors may influence the transition from a lytic to lysogenic state in lambda phage? Describe in
general terms how bacteriophage lambda regulates the switch between the lytic and lysogenic
cycles. Other Proteins involved? Describe in general terms the strategy used by the ssDNA virus
phiX174 to synthesize its nucleic acids and proteins. Function of the replicative form? Know the
different viruses which have a ssDNA genome Outline the major events involved in plus-strand
RNA viruses and the specific mechanisms used to accomplish each step. Type of template used?
Describe in general terms the strategy used by minus and plus strand RNA viruses to synthesize
their nucleic acids and proteins. Propose how a retrovirus with a single RNA molecule as its
genome might generate multiple proteins from that molecule. Intermediate molecule? What are
cytokines? Roles in immunity? What is the alternate complement pathway? Roles? What are
the functions and locations (blood, tissue etc) of the different immune cells? Mechanisms
employed by the lungs to help protect it from infection What are dendritic cells? Roles they play
in the immune response? Specific vs non-specific Function of lysozyme? Know the different
body areas which act as physical barriers to infection. Know the different physical and
biological defense mechanisms? Examples?
Solution
As per the rule i have answered your first question:
Reoviridae: Reoviridae are currently classified into nine genera. The genomes of these viruses
consist of 10 to 12 segments of dsRNA, each generally encoding one protein. The mature virions
are non-enveloped. Their capsids, formed by multiple proteins, have icosahedral symmetry and
are arranged generally in concentric layers. A distinguishing feature of the dsRNA viruses,
irrespective of their family association, is their ability to carry out transcription of the dsRNA
segments, under appropriate conditions, within the capsid. In all these viruses, the enzymes
required for endogenous transcription are thus part of the virion structure.
Orthoreoviruses: The orthoreoviruses (reoviruses) are the prototypic members of the virus
Reoviridae family and representative of the turreted members, which comprise about half the
genera. Like other members of the family, the reoviruses are non-enveloped and characterized by
concentric capsid shells that encapsidate a segmented dsRNA genome. In particular, reovirus has
eight structural proteins and ten segments of dsRNA. A series of uncoating steps and

2. conformational changes accompany cell entry and replication. High-resolution structures are
known for almost all of the proteins of mammalian reovirus (MRV), which is the best-studied
genotype. Electron cryo-microscopy (cryoEM) and X-ray crystallography have provided a
wealth of structural information about two specific MRV strains, type 1 Lang (T1L) and type 3
Dearing (T3D).
Cypovirus: The cytoplasmic polyhedrosis viruses (CPVs) form the genus Cypovirus of the
family Reoviridae. CPVs are classified into 14 species based on the electrophoretic migration
profiles of their genome segments. Cypovirus has only a single capsid shell, which is similar to
the orthoreovirus inner core. CPV exhibits striking capsid stability and is fully capable of
endogenous RNA transcription and processing. The overall folds of CPV proteins are similar to
those of other reoviruses. However, CPV proteins have insertional domains and unique structures
that contribute to their extensive intermolecular interactions. The CPV turret protein contains
two methylase domains with a highly conserved helix-pair/-sheet/helix-pair sandwich fold but
lacks the -barrel flap present in orthoreovirus 2. The stacking of turret protein functional domains
and the presence of constrictions and A spikes along the mRNA release pathway indicate a
mechanism that uses pores and channels to regulate the highly coordinated steps of RNA
transcripti on, processing, and release.
Rotavirus: Rotavirus is the most common cause of acute gastroenteritis in infants and young
children worldwide. This virus contains a dsRNA genome and is a member of the Reoviridae
family. The genome of rotavirus consists of eleven segments of dsRNA. Each genome segment
codes for one protein with the exception of segment 11, which codes for two proteins. Among
the twelve proteins, six are structural and six are non-structural proteins. It is a double-stranded
RNA non-enveloped virus
Bluetongue virus: The members of genus Orbivirus within the Reoviridae family are arthropod
borne viruses and are responsible for high morbidity and mortality in ruminants. Bluetongue
virus (BTV) which causes disease in livestock (sheep, goat, cattle) has been in the forefront of
molecular studies for the last three decades and now represents the best understood orbivirus at
the molecular and structural levels. BTV, like other members of the family, is a complex non-
enveloped virus with seven structural proteins and a RNA genome consisting of 10 variously
sized dsRNA segments.
Phytoreoviruses: Phytoreoviruses are non-turreted reoviruses that are major agricultural
pathogens, particularly in Asia. One member of this family, Rice Dwarf Virus (RDV), has been
extensively studied by electron cryomicroscopy and x-ray crystallography. From these analyses,
atomic models of the capsid proteins and a plausible model for capsid assembly have been
derived. While the structural proteins of RDV share no sequence similarity to other proteins,
their folds and the overall capsid structure are similar to those of other Reoviridae.