Lecture Microbiology - Chapter 10: Viruses. This chapter presents the following content: What are Viruses? Viral shapes and sizes, infectious properties, virus classification, unique RNA virus cycle, antisense virus, ds RNA chromosome,. | VIRUSES CHAPTER 10 Copyright © 2012 John Wiley & Sons, Inc. All rights reserved. What are Viruses? Obligate intracellular parasites Viral components – Nucleic acids – Capsid – Envelope © 2012 John Wiley & Sons, Inc. All rights reserved. Viral Shapes and Sizes Helical Polyhedral Spherical (Enveloped) © 2012 John Wiley & Sons, Inc. All rights reserved. Infectious Properties Viral Host range – From 1 species (polio virus) to many (Influenza virus) Viral specificity – From 1 cell type (Hepatitis B virus) to several (CMV in GIT, lungs, spleen) Viral Origins – ? Co-evolution with cells – ? Degeneration © 2012 John Wiley & Sons, Inc. All rights reserved. Virus Classification 108 families so far – Pathogens for all life forms Classification based upon – – – – Nucleic acid type Single strand vs. double strand chromosome + versus – single strand Enveloped versus “naked" © 2012 John Wiley & Sons, Inc. All rights .
