Question 1

Which microscope bombards a whole, metal-coated specimen with electrons moving back and forth over it?

Accepted Answer

A) fluorescence 
B) differential interference contrast 
C) scanning electron 
D) transmission electron 
E) phase-contrast

Question 2

Which of the following reagents reacts with crystal violet as the mordant?

Accepted Answer

A) Crystal violet 
B) Gram's iodine 
C) 95% ethyl alcohol 
D) Safranin

Question 3

The type of microscope in which you would see brightly illuminated specimens against a black background is

Accepted Answer

A) bright-field. 
B) dark-field. 
C) phase-contrast. 
D) fluorescence. 
E) electron.

Question 4

Which of the following will result when 1% to 5% agar is added to nutrient broth, boiled and cooled?

Accepted Answer

A) a pure culture 
B) a mixed culture 
C) a solid medium 
D) a liquid medium 
E) a contaminated medium

Question 5

A nutrient medium that has all of its chemical components identified and their precise concentrations known and reproducible would be termed

Accepted Answer

A) complex. 
B) reducing. 
C) enriched. 
D) enumeration. 
E) synthetic.

Question 6

The primary purpose of staining cells on a microscope slide is to

Accepted Answer

A) kill them. 
B) secure them to the slide. 
C) enlarge the cells. 
D) add contrast in order to see them better. 
E) see motility.

Question 7

A media is designed that allows only staphylococci to grow.In addition, S.aureus colonies have a yellow halo around them and other staphylococci appear white.This type of media is

Accepted Answer

A) selective only. 
B) differential only. 
C) both selective and differential. 
D) a reducing media. 
E) enriched.

Question 8

Bacteria that require special growth factors and complex organic substances are called

Accepted Answer

A) fastidious. 
B) pathogenic. 
C) harmless. 
D) anaerobic. 
E) aerobic.

Question 9

_____ dyes have a negative charge on the chromophore and are repelled by bacterial cells.

Accepted Answer

The answer of _____ dyes have a negative charge on...

Question 10

A contaminated food sample contains several different species of bacteria.A food microbiologist is interested in studying just one of these species.Describe the sequence of procedures that the microbiologist must perform in order to obtain a pure culture of the bacterial species of interest from this food sample.Detail all the necessary media and equipment.

Accepted Answer

The answer of A contaminated food sample contains several different...

Question 11

How will

Accepted Answer

A) Gram-positive 
B) Gram-negative 
C) Gram-variable 
D) None of these 
E) coli appear if the mordant is not applied?

Question 12

All of the following are diameters of cells that would be resolved in a microscope with a limit of resolution of 0.2 µm except

Accepted Answer

A) 0.2 µm. 
B) 0.2 mm. 
C) 0.1 µm. 
D) 0.3 µm. 
E) 2.0 µm.

Question 13

Explain the difference and significance between a contaminated culture and a mixed culture.

Accepted Answer

The answer of Explain the difference and significance between a...

Question 14

The procedure for culturing a microorganism requires the use of a microscope.

Accepted Answer

A) True 
 B)False

Question 15

The _____ of the microscope holds and allows selection of the objective lenses.

Accepted Answer

The answer of The _____ of the microscope holds and...

Question 16

Basic dyes are

Accepted Answer

A) attracted to the acidic substances of bacterial cells. 
B) anionic. 
C) used in negative staining. 
D) repelled by cells. 
E) dyes such as India ink and nigrosin.

Question 17

The specimen preparation that is best for viewing cell motility is

Accepted Answer

A) hanging drop. 
B) fixed stained smear. 
C) gram stain. 
D) negative stain. 
E) flagellar stain.

Question 18

Brain-heart infusion, trypticase soy agar (TSA), and nutrient agar are all examples of which type of media?

Accepted Answer

A) synthetic 
B) reducing 
C) enriched 
D) nonsynthetic 
E) selective

Question 19

A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium.Following incubation, only the E.coli grows in the culture.What is the most likely explanation?

Accepted Answer

A) The microbiologist used too much inoculum. 
B) The culture is contaminated. 
C) The incubation temperature was incorrect. 
D) The culture medium must be selective. 
E) The culture medium must be differential.

Question 20

All of the following are examples of different types of microbiological media except

Accepted Answer

A) broth. 
B) enriched. 
C) agar. 
D) petri dish. 
E) gelatin.

Exam 3: Tools of the Laboratory: Methods of Studying Microorganisms