Microbiology Microbiology Introduction to Viruses Introduction to Viruses

Living or non-living?

Sarah L. Bacon

Assignment # 11/336

sarahlbacon@hotmail.com

New UnitMicrobiology - Viruses

Micro (small) biology (study of living organisms)

Viruses = Latin for poison Closely linked with many organisms. Source of disease and death including

AIDS, influenza,Ebola,colds

Objectives of today’s lesson

To describe the basic structure and function of a virus

To evaluate the evidence used to classify viruses as living or non-living

The Structure of Viruses

Viruses are non-cellular (they are not composed of cells)

Viruses are composed of four major components:

Capsid/Protein Coat Nucleic Acids Specific receptors Enzymes

Viral Structure + function Capsid/Protein Coat - coats or protects genetic

material of virus Nucleic Acids - either DNA or RNA which takes

over and instructs a host cell on how to produce more virus.

Specific receptors or a tail - located on surface. Allows virus to attach to a specific host cell

Enzymes - Aid viral entry and/or takeover of host cell

Diagrams of Viruses

Viruses - Living or Non-living

Since viruses are non-cellular there is considerable debate about whether they are living or non -living

Evidence that viruses are living

Viruses contain genetic material Viruses consist of other organic materials

such as proteins Viruses often contain enzymes that aid in

replication Viruses replicate using a host cell

Evidence that viruses are non-living

Viruses do not grow Viruses are non-motile Viruses do not respond to stimuli Viruses are able to form crystals and survive

outside of the host cell Viruses are unable to replicate without a host

cell Viruses have no metabolic activity

Review

Viruses are microscopic organisms that impact all other organisms

It can be successfully debated that they are both living and non-living

Viruses have an elegantly simple structure that aids in their survival

The function of viral components relates to their structure

Future explorations

The specificity of virus/host relationships Viral reproduction - the lytic and lysogenic

cycles

Note to Dr. Potter

This is the first power point presentation that I have ever attempted

I am most proud of having figured out how to get the images of virus from the net and into my presentation

I did not fill in the notes page view because the slides provide me with a lesson plan to follow S.B.