Question 1

The key characteristic of lag phase is ________.

Accepted Answer

The lag phase is characterized by the time period where cells are adjusting to their new environment, during which their metabolic activities change but they do not yet grow or divide significantly. This phase precedes the phase of exponential growth.

Question 2

The key characteristic of log phase is ________.

Accepted Answer

During the log phase, also known as the exponential phase, the number of cells increases exponentially. This is a period of rapid growth where cells are actively dividing.

Question 3

________ is the phase of bacterial cell growth where cell numbers decline but not at a constant rate.

Accepted Answer

The Death Phase is the stage in bacterial growth where the number of dying cells surpasses the number of new cells being produced, leading to a decline in the overall population. This decline does not occur at a constant rate because it can be influenced by various factors such as nutrient depletion and accumulation of waste products.

Question 4

Region 1 of the growth curve of bacteria shown in the illustration below depicts the ________ of growth.

Accepted Answer

The answer of Region 1 of the growth curve of...

Question 5

Region 2 of the growth curve of bacteria shown in the illustration below depicts the ________ of growth.

Accepted Answer

The answer of Region 2 of the growth curve of...

Question 6

Region 3 of the growth curve of bacteria shown in the illustration below depicts the ________ of growth.

Accepted Answer

The answer of Region 3 of the growth curve of...

Question 7

Region 4 of the growth curve of bacteria shown in the illustration below depicts the ________ of growth.

Accepted Answer

The answer of Region 4 of the growth curve of...

Question 8

Microbial cell density may be determined using ________. (Select all that apply)

Accepted Answer

The answer of Microbial cell density may be determined using...

Question 9

________ uses either the spread plate or pour plate method.

Accepted Answer

Dilution plating is a microbiological technique that uses either the spread plate or pour plate method to isolate and count the number of viable microorganisms in a sample.

Question 10

________ concentrates low numbers of bacteria before plating.

Accepted Answer

Filtration is used to concentrate low numbers of bacteria from large volumes of liquid before plating, making it easier to detect and quantify the bacteria present.

Question 11

A Petroff-Hausser chamber ________.

Accepted Answer

A Petroff-Hausser chamber is a specialized counting chamber used in microbiology and cell biology to determine the concentration of cells in a liquid sample. It allows for the direct counting of cells under a microscope from a known volume of fluid, thereby enabling the calculation of cells per milliliter in the sample.

Question 12

Spectrophotometry ________.

Accepted Answer

Spectrophotometry is a technique that measures the amount of light absorbed by a sample. In microbiology, it is used for the rapid determination of cell number by measuring the apparent absorbance of light, which correlates with the concentration of cells in the sample.

Question 13

Which of the following methods of measuring cell density would be the best to choose when you know that you do not have a lot of bacteria present in your sample?

Accepted Answer

Filtration allows for the concentration of bacteria from large volumes of sample onto a filter, which is then plated. This method is particularly useful when the bacterial count in the sample is low, as it increases the likelihood of detecting and counting the bacteria after concentration.

Question 14

Which of the following methods of measuring cell density cannot distinguish between living and dead bacterial cells and thus may not provide the data needed in an actual infection or contamination? (Select all that apply)

Accepted Answer

The answer of Which of the following methods of measuring...

Question 15

If the volume of growth medium trapped under the double-lined box shown in the magnification of the Petroff-Hausser chamber is 5 × 10^-5mls, the density of cells in the culture is ________.

Accepted Answer

The answer of If the volume of growth medium trapped...

Question 16

Percent transmittance is equal to ________.

Accepted Answer

The answer of Percent transmittance is equal to ________.

...

Question 17

Absorbance is equal to ________.

Accepted Answer

The answer of Absorbance is equal to ________.

...

Question 18

The viable cell count (cells/ml) from the spread plate method shown below is ________.

Accepted Answer

The answer of The viable cell count (cells/ml) from the...

Question 19

The viable cell count (cells/ml) from the pour plate method shown below is ________.

Accepted Answer