Wed Lab 5 discussion: Discuss aseptic technique and better ways/equipment for sampling. 5 minutes to look at plates Lecture continued Worksheet 1 due Friday. History quiz on Friday.

Special Staining Gram Stain procedure– divides bacteria into two groups. Gram positive – organisms that are stained purple. Gram negative – organisms that retain counterstain color.

Acid-fast staining – to classify those bacteria which retain stain when washed with acids or alcohol.

Growing Bacteria in the Lab Culture and Media

Growth Requirements: energy source a source of carbon required nutrients, proper O 2, pH, temp, etc.

Culture: A population of microorganisms cultivated in a medium

Culture media:. are designed to provide all the essential nutrients in solution for bacterial growth

Pure Culture Culture containing only one species of organism.

Types of Media Liquid – for pure batch cultures Solid – isolation of pure cultures. Agar.

Assignment: Read online textbook section: “Culture Media for the Growth of Bacteria” Page 16 of Word document on CD

Section 3 Survey of the Microbial World

Terminology: Microbiology – study of small living organisms of microscopic size. Protist – a microorganism in the Kingdom Protista. (includes most microorganisms)

Prokaryote - a cell in which the nuclear substance is not enclosed in a membrane. (includes the bacteria)

Eukaryote – a cell that has a definitive or true nucleus (these cells make up the bodies of all non protist organisms)

Virus – obligate intracellular parasitic organism that is smaller than bacteria. They can only reproduce in cells of host organisms.