Question

how would you grow a streptomycin - resistant strain? e. coli bacteria was spread on both agar plates and incubated for 24 hours. if you wanted to grow up a large quantity of streptomycin resistant e. coli, what would you do next? multiple choice pick a colony of bacteria from the streptomycin positive plate and grow it on a streptomycin negative plate. pick a colony of bacteria from the streptomycin positive plate and grow it on a streptomycin positive plate. pick a colony of bacteria from the streptomycin negative plate and grow it on a streptomycin positive plate. pick a colony of bacteria from the streptomycin negative plate and grow it on a streptomycin negative plate.

Explanation:

To grow a large quantity of streptomycin - resistant E. coli, we need to start with bacteria that are already resistant. The streptomycin - positive plate contains resistant bacteria. Growing them on a streptomycin - positive plate ensures the selective pressure that maintains the resistance trait.

Answer:

Pick a colony of bacteria from the streptomycin positive plate and grow it on a streptomycin positive plate.