MacConkey agar is often used to differentiate E. coli from other Gram-negative rods. The recipe for MacConkey agar is given in the table. Suppose you plated a mixed culture of  Escherichia coli,  Bacillus subtilis, and  Streptococcus pyogenes onto a MacConkey agar plate.  Which species would grow, and how would they appear? Why would the others NOT grow?

why is it important that a small amount of inoculum be used in preparation of an agar slant?

Use the dichotomous key in Table 10.2 to identify a gram-positive, catalase (No bubble) coccus. Table 10.2 1 Gram-positive A. Catalase+ 1. Acid from glucose. 2 Glucose-.....*** Micrococcus B. Catalase- 1. Coccus.. 2. Rod.... II. Gram-negative A. Oxidase- 1. Acid from lactose Lactobacillus Citrobacter Uses atric acid....... *.******. ******* a. b. Citric acid-. Escherichia 2. Lactose- a. H2S produced (1) Urease positive... (2) Urease negative... Proteus Salmonella B. Oxidase+ 1. Rod... ....** ..........* .. Neisseria svuomopn 2. . Coccus....* **** .....* ....** Neisseria Pseudomonas Staphylococcus Streptococcus A Moving to the next question prevents changes to this answer.

You are hired in one of the microbiology labs in Memphis and your first assignment to identify microbial samples from a local restaurant. You are given a set of slides and asked to classify the specimens as Gram positive or Gram negative. 9) What makes the bacteria Gram negative?10) Approximately how long would it take you to finish the entire procedure