A bacterial culture contains 106 cells/mL. A serial dilution (each 1/10) was performed to confirm the numbers through a spread plate count. How many dilutions would be required to obtain a countable number of colonies on the plate (between 30-300)? Group of answer choices 4 3 6 2 5

A student performed a spread plate count of a bacterial culture and recorded 32 and 48 colonies on duplicate plates of the 10-4 dilution. What will be the bacterial count (cfu/ml) in the original culture? Group of answer choices 8.0 x 105 4.0 x 107 8.0 x 106 4.8 x 105 3.2 x 105 4.0 x 106 4.8 x 107 8.0 x 107 4.0 x 105 3.2 x 106 4.8 x 106 3.2 x 107 give answers only

Serial dilutions are generally made: Group of answer choices When the appropriate viable count is unknown To reduce the number of colonies to count on agar plates To reach a suitable dilution while minimizing error All of the other answer choices are correct Based on 10-fold dilutions, although other serial dilution factors are possible e.g. 100-fold

In the enumeration of bacteria in a culture by a plate count, all of the following apply when determining the numbers except: Group of answer choices All bacteria in the culture are counted Statistically only plates with between 30-300 colonies should be counted It is assumed that each colony arose from division of one or a few cells All of the answer choices are correct The medium must contain nutrients used by the bacteria

In the viable plate count method, a measured sample of a culture is evenly spread across an agar surface and incubated. Each _____ represents one _____ from the sample. A. cell, cell B. cell, colony C. colony, cell D. species, colony E. generation, cell Question 29 options:

A sample taken from a sewage treatment plant is likely to have too many bacteria to count directly. What would be best done when determining the numbers of viable bacteria in the sample? Group of answer choices Filtration then spread plating the filtrate Serial dilution and spread plating the dilutions 16-streak plating of the wastewater sample All of the other answer choices are correct Optical density reading in a spectrophotometer