MMG 301 Lecture Notes - Lecture 9: Pressure Cooking, Petri Dish, Yeast Extract
24 Sep 2016
School
Department
Course
Professor
Document Summary
Agar: dissolves in water at 100 degrees, gels below 42 degrees. Know all chemicals and concentrations in medium: complex (undefined) Only the minimal nutrients needed to create more complex molecules needed: enriched. Saves the cell energy, they grow faster. Colonies: when pure, everything is the same. Isolated on agar: not pure when colonies are touching. Selective medium: has an ingredient that inhibits growth of some microorganisms. Differential medium: biochemical test, example: acid production. Diagnostics may use a medium that is both selective and differential: growth dependent tests. Everything must be sanitized before use: heat. 121 degrees, 15 lbs/in2, 15 minutes: filtration. If a medium has a heat sensitive ingredient or external component, use in place of autoclave. Prevents contamination of pure culture via airborne microbes. Procedure: heat inoculation loop, remove cap with culture, flame to sanitize, loop enters tube, tube is reflamed, tube recapped. Petri dish used for streaking cells: separates individual cells, use inoculation loop.
