Limitations of microbial growth - Midterm 1

Question 1

Limits of Spectrophotometer

Answer 1

Does not provide direct info on the concentration and the cell numbers

Question 2

True or false: its possible to determine the concentration of a culture from the optical density alone.

Answer 2

False

Question 3

Why do we use spectrophotometer?

Answer 3

to measure the density of a culture . it provides a good indication of whether the density of a culture is higher or lower than a different or previously measured culture

Question 4

Limitation of Hemocytometer

Answer 4

counts all of the cells including the dead ones. what if we want to only know how many are alive?

Question 5

Purpose of hemocytometer?

Answer 5

allowing someone to obtain an exact count of the number of cells/ml for a given culture.

Question 6

Advantage of hemocytometer

Answer 6

more rapid than plating method and

very precise for determining the total number of cells/ml

Question 7

Purpose of viable cell count?

Answer 7

Allows you to determine a viable cell count

Question 8

Limitations of viable cell count?

Answer 8

takes a long time to do, one has to wait 24 hours to let colonies grow.

Question 9

how does spectrophotometer work?

Answer 9

light source shines a beam of light through a sample and a photometer on the opposite side measures the intensity of light that is able to pass through the solution

Question 10

at what wavelength do we measure the yeast cells with the spectrophotometer?

Answer 10

600nm

Question 11

What is transmitted light?

Answer 11

light that passes through a sample

Question 12

What is a spectrophotometer?

Answer 12

a device that measures the fraction of light that is able to pass through a solution