FDSC 200 Lecture Notes - Lecture 12: Okra, Amylase, Hans Christian Gram

• School: McGill University
• Department: Food Science
• Course: FDSC 200
• Professor: Lawrence Goodridge

Document Summary

Chapter 17: microbiology is the study of living organisms too small to be seen by the unaided human eye, organisms that are only visible through a microscope are called microorganisms or microbes. They multiply rapidly, transfer from one surface to another easily: bacteria, yeasts and molds have positive uses in foods. They depend on outside sources to grow and multiply. Yeasts and molds are fungi: bacteria are small single-celled organisms that multiply through cell division. Bacteria cells have rigid walls and no nucleus. The cells are filled with a gelatinous liquid called cytoplasm, where metabolism and reproduction take place. Bacteria are classified by shape, cell wall structure and o2 needs: rod-shaped bacteria are called bacilli. Spiral bacteria are called spirilla: bacteria have 2 basic types of cell wall structures identified by their ability to be stained by a crystal violet dye called gram"s stain (hans christian gram, 1884). Gram-positive cell walls turn blue-violet, gram-negative cells turn red.