6-1 PL Quiz

Question 1

what allows microbiologists to estimate the population density in a liquid sample

Answer 1

standard plate count

Question 2

how does the standard plate count work

Answer 2

by plating a very dilute portion of the sample and counting the number of colonies it produces

Question 3

the inoculum that is transferred to the plate contains a ________ _______ of the original sample

Answer 3

known proportion

Question 4

what is the inoculum a product of

Answer 4

serial dilution

Question 5

tubes containing a known volume of sterile diluent (water, saline, or buffer)

Answer 5

dilution blanks

Question 6

what is serial dilution

Answer 6

a series of controlled transfers down a line of dilution blanks

Question 7

what is the cell density usually reduced to at each step

Answer 7

1/10 or 1/100

Question 8

this contains between 30 and 300 colonies

Answer 8

countable plate

Question 9

what is considered statistically unreliable

Answer 9

a count lower than 30 colonies

Question 10

formula used to calculate dilutions

Answer 10

V1D1=V2D2

Question 11

what does CFU stand for

Answer 11

colony forming units

Question 12

this is actually the number of colonies that develop on the plate

Answer 12

CFU

Question 13

how do you calculate the original cell density

Answer 13

OCD=CFU/DxV