137 in Action Exercise 3-4: Learning in Action 1. With MacConkey agar, what would be the...

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137 in Action Exercise 3-4: Learning in Action 1. With MacConkey agar, what would be the possible consequence of: a. replacing the lactose with glucose? Replacing the lactose w/ glucose would defeat the ability to differentiate between fermenting gram negative organisms and ta those that can't ferment lactose. b. replacing the neutral red with phenol red (yellow when acidic; red or pink when alkaline)? 2. How would removing the crystal violet from MacConkey agar alter the sensitivity and specificity of the medium? 3. MacConkey agar is a selective medium. Is it also a defined or an undefined medium? Why is that formulation desirable? 4. Do Gram-positive bacteria grow on MacConkey agar? If not, what prevents their growth? 137 in Action Exercise 3-4: Learning in Action 1. With MacConkey agar, what would be the possible consequence of: a. replacing the lactose with glucose? Replacing the lactose w/ glucose would defeat the ability to differentiate between fermenting gram negative organisms and ta those that can't ferment lactose. b. replacing the neutral red with phenol red (yellow when acidic; red or pink when alkaline)? 2. How would removing the crystal violet from MacConkey agar alter the sensitivity and specificity of the medium? 3. MacConkey agar is a selective medium. Is it also a defined or an undefined medium? Why is that formulation desirable? 4. Do Gram-positive bacteria grow on MacConkey agar? If not, what prevents their growth?

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Answer 1 a It would be impossible to distinguish between bacterial strains b acid manufacturers woul... View the full answer