Question 1

The events of binary fission are
I. the cell doubles in size
II. the DNA is replicated
III. the cell forms a septum
IV. the cell separates from its offspring
The CORRECT order of these events is

Accepted Answer

A)  I, III, II, IV. 
B)  II, III, I, IV. 
C)  IV, I, III, II. 
D)  II, I, III, IV. 
E)  I, II, IV, III.

Question 2

A cell that uses an organic carbon source and obtains energy from light would be called a

Accepted Answer

A)  photoheterotroph. 
B)  lithoautotroph. 
C)  photoautotroph. 
D)  chemoheterotroph. 
E)  chemoautotroph.

Question 3

Ted heats some food just to boiling, and stores some of it immediately in a container which he places in the refrigerator. A week later he takes the food out and finds it has spoiled. The microbes responsible are probably

Accepted Answer

A)  thermoduric. 
B)  thermophiles. 
C)  mesophiles. 
D)  hyperthermophiles. 
E)  psychrophiles.

Question 4

Genetic methods of detecting microorganisms reveal that the number of bacterial species in nature exceeds previous estimates by several orders of magnitude. In human mouths, for example, it is estimated that 500-700 microbial species are normally present. Explain why previous estimates were low.

Accepted Answer

The answer of Genetic methods of detecting microorganisms reveal that...

Question 5

An aquatic microbe that can grow only near the surface of the water is probably which of the following?

Accepted Answer

A)  a phototroph 
B)  a heterotroph 
C)  a chemotroph 
D)  a lithotroph 
E)  an anaerobe

Question 6

A(n) (autotroph/lithotroph/organotroph) uses inorganic molecules as electron donors.

Accepted Answer

The answer of A(n) (autotroph/lithotroph/organotroph) uses inorganic molecules as electron...

Question 7

Pure cultures are often obtained by isolating

Accepted Answer

A)  streaks. 
B)  broths. 
C)  CFUs (colony forming units). 
D)  inoculums. 
E)  specimens.

Question 8

The (maximum/optimum/selective) growth temperature is the temperature at which an organism exhibits the highest growth rate.

Accepted Answer

The answer of The (maximum/optimum/selective) growth temperature is the temperature...

Question 9

A 0.1 ml sample of a log phase culture contains 10,000 bacterial cells/ml. It is added to 9.9 ml of fresh culture medium broth. Assume a generation time of 30 minutes, and no limiting nutrients. How many bacteria will be present in the entire broth culture after five hours?

Accepted Answer

A)  3.2 × 10⁴ 
B)  5.0 × 10⁵ 
C)  1.02 × 10⁶ 
D)  6.0 × 10⁶ 
E)  2.56 × 10⁷

Question 10

A microbiologist inoculates a flask of broth to a concentration of 100 bacterial cells per ml. The generation time of the species is 1 hour, and there is no lag phase. How long will it be before the culture contains more than 6,000 cells per ml?

Accepted Answer

A)  12 hours 
B)  6 hours 
C)  2 hours 
D)  4 hours 
E)  10 hours

Question 11

Which of the following methods provides information about the number of living cells in a sample of bacterial culture?

Accepted Answer

A)  serial dilution and viable plate count 
B)  membrane filtration 
C)  a Petroff-Hauser counting chamber 
D)  flow cytometry 
E)  a Coulter counter

Question 12

An epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue cells in clinical samples from victims. The scientist wants to try to isolate the bacteria in the lab. What culture conditions are most likely to be successful?

Accepted Answer

A)  culturing on blood agar plates 
B)  inoculation of EMB plates 
C)  incubation in an anaerobic culture system 
D)  inoculation of cell cultures 
E)  inoculation of a minimal medium broth

Question 13

Agar is a useful compound in the microbiology lab because it is an excellent nutrient for bacteria.

Accepted Answer

A) True 
 B)False

Question 14

The only effective way to store bacterial cultures for short periods of time is to arrest their metabolism by freezing.

Accepted Answer