Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
The following steps are required for making cheese. What is the second step?
1)
A)
inoculation with lactic acid bacteria
B)
inoculation with Penicillium
C)
enzymatic coagulation of milk
D)
fermentation of curd
E)
separation of curds and whey
2)
Thiobacillus ferrooxidans is used for the recovery of _________ from ore.
2)
A)
sulfuric acid
B)
sulfur
C)
gold
D)
copper
E)
iron
3)
All of the following are reasons for utilizing algae for biofuel production EXCEPT
3)
A)
they can utilize agriculturally poor land.
B)
they do not take up land needed for food production.
C)
they produce a nondegradable waste product.
D)
they produce more energy per acre than corn.
E)
their main requirement is abundant light.
4)
Bioreactors are widely used for industrial fermentation. Which of the following conditions must be
closely monitored for optimal fermentation?
4)
A)
temperature
B)
pH
C)
oxygen levels
D)
both temperature and pH
E)
temperature, pH, and oxygen levels
5)
What will be produced if wine is aerated?
5)
A)
CH4
B)
acetic acid
C)
ethanol + CO2
D)
CO2+ H2O
E)
None of the answers is correct.
6)
What process does yeast use to produce ethanol for automobile fuel from corn?
6)
A)
oxidation
B)
fermentation
C)
photosynthesis
D)
anaerobic respiration
E)
the Krebs cycle
Explanation:
7)
In Figure 28.1, assume the cells are your desired product and you want to maintain a continuous
culture. When would you harvest cells to maximize your yield?
7)
A)
a
B)
b
C)
c
D)
d
8)
Microorganisms themselves are commercial products. Which of the following microbes is available
as a product sold in retail stores?
8)
A)
Lactobacillus
B)
Rhizobium
C)
Bacillus thuringiensis
D)
Saccharomyces
E)
All of these organisms can be found in various commercial products.
9)
Commercial sterilization of processed canned foods uses a 12D treatment which is based upon a
theoretical population of 1012 C. botulinum endospores in a can of food. After treatment, there
would theoretically be how many endospores left?
9)
A)
10 endospores
B)
100 endospores
C)
1 endospore
D)
12 endospores
E)
0 endospores
Figure 28.1
10)
In Figure 28.1, assume the cells are producing penicillin which is collected during the idiophase.
When would you be able to collect the penicillin?
10)
A)
a
B)
b
C)
c
D)
d
11)
All of the following are industrial enzymes made by microbial fermentations EXCEPT
11)
A)
proteases.
B)
glucose isomerase.
C)
rennin.
D)
vitamin C.
E)
amylases.
12)
Which of the following microorganisms is usually used in the fermentation of alcoholic beverages?
12)
A)
Rhizopus
B)
Penicillium
C)
Propionobacterium
D)
Lactobacillus
E)
Saccharomyces
13)
A baker forgets to put yeast in his bread dough. Which of the following do you expect to happen to
the bread as a result?
13)
A)
The bread will not rise.
B)
The bread will look normal but will be tough.
C)
It will take longer to bake.
D)
Bacterial contaminants will now be able to grow.
E)
The bread will have a sour taste.
14)
All of the following foods are produced using microbial fermentations EXCEPT
14)
A)
yogurt.
B)
ketchup.
C)
coffee.
D)
sauerkraut.
E)
sour cream.
15)
All of the following are advantages of a bioreactor instead of a flask culture EXCEPT
15)
A)
aseptic sampling.
B)
uniform aeration and mixing.
C)
instrumentation for monitoring environmental conditions.
D)
larger culture volumes can be grown.
E)
None of the answers is correct; all of these are advantages of using a bioreactor instead of a
flask culture.
Figure 28.3
16)
Figure 28.3 shows the growth curves of Acetobacter under different conditions. Which culture would
produce the highest amount of the primary metabolite acetic acid?
16)
A)
a
B)
b
C)
c
D)
d
E)
e
17)
Aseptic packaging works to preserve foods through
17)
A)
creation of an anaerobic environment.
B)
mutation of bacterial DNA.
C)
creation of an anaerobic environment and high heat.
D)
exposure to high heat.
E)
increasing pH.
18)
Commercial sterilization differs from complete sterilization in that commercial sterilization
18)
A)
employs a higher temperature.
B)
kills only bacteria.
C)
may result in the survival of thermophiles.
D)
may result in the survival of fungal spores.
E)
kills all microorganisms.
19)
Canning preserves food
19)
A)
by exposure to high heat.
B)
through use of aseptic packaging.
C)
by exposure to high pH.
D)
by exposure to radiation.
E)
by exposure to chemicals.
20)
Biomass is a renewable energy source derived from the organic matter produced by living
organisms. All of the following are sources of biomass EXCEPT
20)
A)
crops.
B)
landfill sites.
C)
algae.
D)
oxidation of metals.
E)
bacteria.
21)
All of the following are uses for radiation EXCEPT
21)
A)
sterilizing spices.
B)
inactivation of Trichinella larvae.
C)
heating cold food.
D)
prevention of sprouting.
E)
killing of insect eggs and larva.
22)
Spoilage of canned foods stored at high temperatures, accompanied by gas production, is
22)
A)
putrefactive anaerobic spoilage.
B)
caused by acid–tolerant fungi.
C)
spoilage by mesophilic bacteria.
D)
flat sour spoilage.
E)
thermophilic anaerobic spoilage.
23)
Which of the following pertains to an improperly canned food product on a store shelf that bulges
from microbial activity?
23)
A)
mesophilic spoilage
B)
flat sour spoilage
C)
thermophilic anaerobic spoilage
D)
hydrogen sulfide spoilage
E)
bacterial soft rot
24)
What role do lactic acid bacteria play in cheese production?
24)
A)
providing characteristic flavor and smell
B)
production of holes in Swiss cheese
C)
curd formation
D)
ripening the cheese
E)
Lactic acid bacteria carry out each of these roles in cheese production.
25)
You are growing Bacillus subtilis in a bioreactor and notice that the growth rate has slowed and the
pH has decreased. You suspect the bacteria are
25)
A)
photosynthesizing.
B)
using proteins.
C)
fermenting.
D)
using the Krebs cycle.
E)
dead.
26)
Which of the following pairs is mismatched?
26)
A)
Bacillus beer
B)
Acetobacter vinegar
C)
Lactobacillus yogurt
D)
Propionibacterium Swiss cheese
E)
Penicillium blue cheese
27)
As cheese ages, it gets
27)
A)
saltier.
B)
more protein.
C)
more acidic.
D)
more alcoholic.
E)
more whey.
28)
In Figure 28.1, assume that a secondary metabolite is your desired product. When would you be
able to obtain it?
28)
A)
a
B)
b
C)
c
D)
d
29)
Canning works to preserve foods through
29)
A)
exposure to high heat.
B)
increasing pH.
C)
mutation of bacterial DNA.
D)
creation of an anaerobic environment.
E)
creation of an anaerobic environment and high heat.
30)
Xanthan used in household products is produced by bacteria
30)
A)
selected for their ability to utilize lactose.
B)
that are plant pathogens.
C)
that were genetically modified.
D)
that were irradiated to mutate them.
E)
selected for their ability to utilize lactose and that are plant pathogens.
31)
Which of the following reactions makes wine less acidic?
31)
A)
ethanol
acetic acid
B)
sugar
CO2+ H2O
C)
carbon dioxide
sucrose
D)
sugar
ethanol
E)
malic acid
lactic acid
32)
All of the following are true of irradiation methods used for food preservation and sterilization
EXCEPT
32)
A)
they greatly reduce the number of pathogens present in meats and poultry.
B)
residual radioactivity is left behind on many foods.
C)
they prolong shelf–life of fruits and vegetables.
D)
ionizing radiation such as X rays or gamma rays is used.
E)
they are used for the sterilization of many spices.
33)
All of the following are industrial products produced using microbial fermentations EXCEPT
33)
A)
aspartame.
B)
saccharin.
C)
citric acid.
D)
monosodium glutamate.
E)
riboflavin.
34)
You are growing Bacillus subtilis in a bioreactor and notice that the growth rate has slowed and the
pH has decreased. What could you add?
34)
A)
peptides
B)
lactose
C)
oxygen
D)
glucose
E)
lactic acid
35)
Which of the following reactions is performed by yeast in wine–making?
35)
A)
malic acid
lactic acid
B)
sugar
CO2+ H2O
C)
ethanol
acetic acid
D)
carbon dioxide
sucrose
E)
sugar
ethanol
36)
Microorganisms play an active role in the formation of industrial products. Which of the following
is mismatched?
36)
A)
Bacillus thuringiensis – insecticide
B)
algae – citric acid
C)
Saccharomyces cerevisiae – for fermentation
D)
Rhizobium – increases nitrogen in the soil
E)
Penicillium – treatment of disease
37)
Aseptic packaging utilizes which of the following to sterilize laminated paper or plastic prior to
filling with food?
37)
A)
X rays
B)
hot hydrogen peroxide solution
C)
autoclave
D)
gamma radiation
E)
hot HCl solution
38)
All of the following are fuels produced by microorganisms EXCEPT
38)
A)
methane.
B)
hydrogen.
C)
ethanol.
D)
cellulose.
E)
oil from algae.
39)
Which of the following is an undesirable contaminant in wine–making?
39)
A)
Bacillus
B)
Acetobacter
C)
Clostridium
D)
Saccharomyces
E)
lactic acid bacteria
40)
Microbial products can be improved by all of the following EXCEPT
40)
A)
modifying culture conditions.
B)
genetically modifying strains.
C)
sterilization.
D)
isolating new strains.
E)
mutating existing strains.
41)
All of the following are industrial products produced by microbes EXCEPT
41)
A)
vitamin B12 and riboflavin.
B)
uranium.
C)
antibiotics.
D)
industrial enzymes.
E)
amino acids in food supplements.
42)
Which of the following microbes produces a natural biopesticide?
42)
A)
Saccharomyces cerevisiae
B)
Thiobacillus ferroxidans
C)
Lactobacillus buggaricus
D)
Bacillus thuringiensis
E)
Penicillium chryssogenum
43)
Spoilage of canned foods due to inadequate processing, NOT accompanied by gas production, is
43)
A)
flat sour spoilage.
B)
thermophilic anaerobic spoilage.
C)
putrefactive anaerobic spoilage.
D)
caused by acid–tolerant fungi.
E)
spoilage by mesophilic bacteria.
44)
Radiation works to preserve foods through
44)
A)
creation of an anaerobic environment and high heat.
B)
lethal mutation of bacterial DNA.
C)
creation of an anaerobic environment.
D)
exposure to high heat.
E)
increasing pH.
45)
Which of the growth curves in Figure 28.3 will give the highest yield of a secondary metabolite?
45)
A)
a
B)
b
C)
c
D)
d
E)
e
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
46)
Rhizobium and Bradyrhizobium are mixed with peat moss to increase nitrogen fixation.
46)
47)
The blue–green clumps observed in Roquefort cheese are a result of mold growth.
47)
48)
Industrial canning is achieved using a pressure cooker which operates in a manner similar to an
autoclave.
48)
49)
A large industry exists based on the synthesis of amino acids by microorganisms.
49)
50)
If an industrial microbiologist works with Thiobacillus ferrooxidans, he is likely to be involved in
copper mining.
50)
51)
The longer interior–ripened cheeses are permitted to ripen, the milder the taste of the cheese.
51)
52)
Vitamins A, B12, and E are commonly produced by microorganisms.
52)
53)
Mesophilic bacteria grow best at temperatures of 60°C.
53)
54)
The production of vinegar relies on the microbial oxidation of ethanol to acetic acid.
54)
55)
High–pressure processing of foods such as deli meats and precooked chicken strips targets
pathogens such as C. botulinum.
55)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
56)
Discuss the production of three different non–food/beverage substances that utilize microorganisms in their
production. Your discussion should include the specific microorganisms involved and their role in the
production of each substance.
57)
Vessels used for industrial fermentation reactions are known as bioreactors. Explain the difference between
batch production and continuous flow production using a bioreactor.
58)
Discuss the production of four different foods that require microbial fermentation in their products. In your
discussion, name the specific microorganisms used and describe the fermentation by–product(s) needed for the
production of each food item.
59)
Explain how ionizing radiation can be used to preserve foods. Discuss its advantage over canning as a method
of preservation.
Answer Key
Testname: C28
Answer Key
Testname: C28