MICR 2420 Study Guide - Midterm Guide: Homeostasis, Growth Medium, Cyclic Adenosine Monophosphate

• School: University of Guelph
• Department: Microbiology
• Course: MICR 2420
• Professor: Steven Seah

Document Summary

Bacteria need to be in liquid in order to be counted. Solid samples must be suspended in liquid. Expressed in terms of: #bacteria/ml of liquid, #bacter/g of solid. Microorganisms are counted directly by placing dilutions on a special slide called a petroff- Slide has wells and an etched grid. Within the large square, it can hold 8. 0 x10-6, there is 7 microbes. Theory is that one bacteria can form a colony. Important to dilute so you don"t have too many colonies form. Fluorescent tagged cells are passed through a small orifice and passed a laser. Detectors measure light scatter in the forward direction (measure of particle size) and to the side (particle shape or granularity) Very expensive, and few labs have them. Need right dilution for countable number of colonies. It dirty, it will count dirt particles as cells. Bacteria divide by binary fission, where one cell makes two. Bacteria x 2^(number of divisions) = total bacteria.