Lab Exam Final Micro 260 Verified Questions And Answers 2024 Latest Version

Unknown II and EnteoPluri-Test Interpret the results of colonies grown on MacConkey and PEA agar {Ans: MacConkey agar only grows gram-negative bacteria Lactose fermenting strains grow as red or pink and may be surrounded by a zone of acid precipitated bile. PEA gram-positive Staphylococcus species and Streptococcus species}aerotolerance Know which components of the medium reduce oxygen to water {Ans: asorbic acid reacts with o2 to form dehydro-ascorbic acid and water}MacConkey (MAC) Agar Name the selective agent and the only fermentable carbohydrate in MacConkey agar {Ans: Bile salts and crystal violet are the selective agents, inhibiting Gram-positive organisms and allowing Gram- negative bacteria to grow. Lactose is the fermentable carbohydrate. Sodium Chloride maintains the osmotic balance of the medium}Casein and Starch Hydrolysis Know if casein is a carbohydrate, lipid or protein {Ans: Casein protein is a protein found in milk that gives milk its white color. Cow's milk consists of around 80% casein protein}PEA Determine if an organism is Gram-positive or Gram-negative based on growth on PEA and nutrient agar {Ans: (PEA) agar allows growth of gram-positive organisms, particularly cocci, while inhibiting most gram-negative bacteria and fungi. PEA prevents the growth of Gram-negative organisms by disrupting