BIO 255 (BIO)

Selective and Differential plates: EMB: Gram negative rods grow Uses dyes eosin Y and methylene blue to inhibit Gram positive Gram negative rods are differentiated based on their ability of ferment lactose Slower fermenters: pink Medium fermentors: purple Fast fermentors: green Non-fermenters: light, translucent color MAC: Gram negative rods grow Uses crystal violet and bile salts to inhibit Gram positive Gram negative rods are differentiated based on their ability

Gram Stain Positive: Purple Negative: Pink 1. 4-5 layers 2. Crystal Violet 3. Iodine 4. Decolorizer 5. Safrin 2. Bacteria Shape Bacillus: rod shaped Coccus: round shape Spiral: spiral shaped 3. Catalase Test Hydrogen peroxide is toxic to bacteria and may be produced in the cell. Some bacteria contain catalase which can detoxify the hydrogen peroxide by converting it to water and gaseous oxygen. Positive: Bubbles Negative: Nothing happens Oxygen gas comprises the bubbles 4. Oxid...

BIO 255 Exam I Study Guide Basic topics: you need to fill in the details! Chapters 1, 3 + readings from 6, 4, 5, 8 Species mentioned/discussed: E. coli (Escherichia coli) I. Honors the discoverer, Thomas Escherich II. Coli describe the bacterium’s habitat (Colon) III. Originally Bacterium coli IV. “Graduate” bacteria A. Uses mixed acid fermentation Staphylococcus aureus I. Found on skin Neisseria gonorrhoeae I. Most are human cell pathogen A. Stick to tongue tissue II. Epithe...