Microbiology lab exam 2 Questions and Answers 100% Pass

Microbiology lab exam 2 Questions and Answers 100% Pass gram-positive - appear purple gram-negative - appear pink Isolation by Dilution - -reducing number of bacteria so that individual colonies may be isolated -streak plate technique is commonly used to separate mixed cultures to isolate colonies that can be used to make a pure culture Selective media - promotes the growth of some organisms and inhibits the growth of others Differential media - show different growth characteristics for certain organisms, such as a color change TSA - Tryptic Soy Agar 2 100% Pass Guarantee Katelyn Whitman, All Rights -neither selective nor differential MSA - Mannitol Salt Agar -both selective and differential -selects for salt tolerant (halophiles) -differential- mannitol fermenters change media from red to yellow EMB - Eosin Methylene Blue Agar -both selective and differential -selects for gram-negative and inhibits gram-positive -differential- lactose fermenters exhibit metallic green sheen Carbohydrate Catabolism labs - Starch hydrolysis and OF glucose deeps Starch hydrolysis - -differential test -if starch is no longer in media, the bacteria will test positive for amylase -Flood agar with iodine; iodine will turn media purple if it contains starch -positive result will have zone of clearing and no color change in media 3 100% Pass Guarantee Katelyn Whitman, All Rights -negative result will have no zone of clearing and color change of media to dark purple OF glucose deep - Oxidative/Fermentative -blue/green -one tube is covered with mineral oil to create anaerobic conditions -positive result is color change in media from green to yellow indicating acid production; negative result is no color change