MICROBIOLOGY Introduction Viruses INTRODUCTION Microbiology studies the microscopic

MICROBIOLOGY Introduction Viruses

INTRODUCTION Microbiology studies the microscopic world Leeuwenhoek - Father of microscopy - Made significant Improvements to the microscope Pasteur – father of microbiology http: //www. biography. com/people/louis-pasteur 9434402

INTRODUCTION Included in this unit: Viruses – noncellular particles Monera (Archaebacteria and Eubacteria) – single-celled with no membrane bound organelles, prokaryotic Protista – single-celled with membrane bound nucleus and organelles, eukaryotic

OUR GOAL IN THIS SECTION Evaluate the evidence used to classify viruses as living or non-living

VIRUSES Living or Nonliving Structure

ARE VIRUSES LIVING? Living things must meet the following criteria: Cellular Have a metabolism Have a life span Reproduce Respond to their Environment We will revisit this question after learning more about viruses.

VIRUSES: AN INTRODUCTION Edward Jenner and The Small Pox Story http: //www. youtube. com/watch? v=j. Jw. GNPRmy. TI Human diseases: HIV West Nile SARS Ebola Studying these viruses could be very dangerous to one’s health. . . Most studied virus is the bacteriophage Infects Escherichia coli (E. coli)

STRUCTURE Non-cellular Various sizes and shapes Basically a nucleic acid surrounded by a protein coat (capsid) Can contain DNA or RNA

PROTEIN COAT- THE CAPSID Proteins on the surface of both cells and viruses Some provide structure and shape Can be enzymes Can move things in and out of a cell Use ATP to create movement

VIRAL SPECIFICITY Related to the protein coat To infect a cell the virus must match the proteins on the surface the cell it infects That is why there are viruses that infect humans and not other animals (and vice versa) Antigens markers (molecular markers)

ENCAPSULATED VIRUSES Gain a membranous envelope from their host cell during infection cycle Acts like a camouflage that hides the virus from the host immune system The envelope contains matching proteins to the host cell

ASSIGNMENT Revisit the living criteria… are viruses living or nonliving? Create a T-chart of living vs nonliving characteristics of viruses