1. Subject: Molecular Virology Instructor: Dr. Sobia Manzoor
VIRUSES
AN INTRODUCTION
Subject: Molecular Virology
Instructor: Dr. Sobia Manzoor
Lecture: 1

2. INTRODUCTION TO VIROLOGY
Virology: study of small biological entities : Viruses
Living organisms: consists either of viruses;
1: Parasites
2: Viral genes incorporated in the genome of a living organism.
Viruses; the smallest of creatures have a great impact on the molecular mechanisms of a living organism.
Since viruses are parasitic in nature therefore the study of viral
genome, viral processes of gene expressions in host cells and
viral replication provides fundamental information regarding the
cellular processes in general. .

3. Viral Entry
Viral Persistence
Pathogenesis of Viral Infections
Host Virus Interactions
Viral Immunopathogenesis
Tumor Biology of Viruses
Definition: Simplest of all definitions quoted by the author S. E. Luria states that “Viruses are submicroscopic entities, capable of being introduced into specific living cells and of reproducing inside such cells only”.

4. Viruses differ from each other on various bases.
They differ on the basis of type of host they infect.
On the other hand viruses they may be distinguished from one another:
Morphology
Genome type or
Mode of replication.

5. There are some unifying principles which all viruses follow:
Viral genome is always packaged inside the core of a particle in order to ensure safe transfer from one host to another
In order to survive, all viruses establish themselves in a host population.
The viral genome consists of all the information required for the initiation and completion of an infectious cycle within a host cell that is rendered susceptible to that specific infection.

6. Study of Viruses - Virology
Five Kingdoms
Plantae
Animalia
Fungi
Protista
Monera

7. Five Characteristics of Life
1. Cells. 2. Grow and maintain their structure by taking up chemicals and energy from the environment. 3. Respond to their external environment 4. Reproduce and pass on their organization to their offspring. 5. Evolve and Adapt to their environment.

8. Viruses are: Acellular. Obligate intracellular parasites.
No ATP generating system.
No Ribosomes or means of Protein Synthesis.

9. Typical Virus Two parts 1. Nucleic Acid 2. Capsid (Coat Protein)
DNA or RNA (But never both)
2. Capsid (Coat Protein)
Some Viruses:
Envelope
Enzymes

10. Host Range Spectrum of host cells that a virus can infect
Some viruses only infect:
Plants
Invertebrates
Protists
Fungi
Bacteria (bacteriophages)

11. Host Range
Most viruses have a narrow host range Polio virus - nerve cells Adenovirus - cells in upper Respiratory Tract

12. Course Outcomes:
At the end of the course the student will have a good understanding of fundamental concepts of structure and replication of virus. The course will help student to understand fundamental aspects on the effect of virus on eukaryotic and prokaryotic organisms. After reading the course the student will have elaborate knowledge of morphology, taxonomy, mechanisms of replication, strategies of viral gene expression, diseases and biological control of viruses. 

13. Course Contents:
200 years of discoveries
General aspects of virology
Viral Classification and Structure
Modes of infection
Cellular Models of virus propagations
Replication and pathogenesis in a comparative fashion.
Host-virus interactions
Transformation and oncogenesis
Immunopathology
Host defense mechanisms
Antiviral pharmacology and applied virology
Bacteriophages
Plant viruses and their associated diseases
What is next for Virology?