Question

1. in the appropriate space in table 1 below, record the results you expect to obtain after incubation. use (+) for bacterial growth (i.e., resistance to the antibiotic) and (-) for lack of growth (i.e., sensitivity to the antibiotic). in the space below the table, explain your reasoning.

table 1. growth of e. coli strains i and ii on plates used to confirm the strains’ resistance or sensitivity to streptomycin and ampicillin.

Explanation:

Step1: Understand LB plate

LB plate is a general - purpose growth medium with no antibiotics. So both strains are expected to grow and observed to grow, as indicated by (+).

Step2: Analyze LB+str plate

Strain I is resistant to streptomycin (str), so it is expected and observed to grow (+). Strain II is sensitive to str, so it is expected and observed to not grow (-).

Step3: Examine LB+amp plate

Strain I is sensitive to ampicillin (amp), so it is expected and observed to not grow (-). Strain II is resistant to amp, so it is expected and observed to grow (+).

Step4: Consider LB+str+amp plate

Strain I is resistant to str but sensitive to amp. So it is expected to grow but observed not to grow due to ampicillin. Strain II is resistant to both str and amp, so it is expected to grow but observed not to grow, which may be due to experimental error or other unforeseen factors.

Answer:

The table results are as follows:

Type of Plate	Strain I - Expected Results	Strain I - Observed Results	Strain II - Expected Results	Strain II - Observed Results
LB+str	+	+	-	-
LB+amp	-	-	+	+
LB+str+amp	+	-	+	-