Exam 6 microbiology part 2 Flashcards


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1

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?
A) It will take longer to bake.
B) Bacterial contaminants will now be able to grow.
C) The bread will not rise.
D) The bread will look normal but will be tough.
E) The bread will have a sour taste.

C) The bread will not rise.

2

Spoilage of canned foods stored at high temperatures, accompanied by gas production, is
A) thermophilic anaerobic spoilage.
B) flat sour spoilage.
C) spoilage by mesophilic bacteria.
D) caused by acid-tolerant fungi.
E) putrefactive anaerobic spoilage.

A) thermophilic anaerobic spoilage.

3

Spoilage of canned foods due to inadequate processing, NOT accompanied by gas production, is
A) thermophilic anaerobic spoilage.
B) flat sour spoilage.
C) spoilage by mesophilic bacteria.
D) caused by acid-tolerant fungi.
E) putrefactive anaerobic spoilage.

B) flat sour spoilage.

4

Which of the following pairs is mismatched?
A) Propionibacterium — Swiss cheese
B) Penicillium — blue cheese
C) Lactobacillus — yogurt
D) Acetobacter — vinegar
E) Bacillus — beer

E) Bacillus — beer

5

Which of the following pertains to an improperly canned food product on a store shelf that has a bad odor and putrefaction of the canned material?
A) mesophilic spoilage
B) flat sour spoilage
C) bacterial soft rot
D) thermophilic anaerobic spoilage
E) hydrogen sulfide spoilage

A) mesophilic spoilage

6

All of the following are fuels produced by microorganisms EXCEPT
A) cellulose.
B) ethanol.
C) hydrogen.
D) methane.
E) oil from algae.

A) cellulose.

7

Microorganisms play an active role in the formation of industrial products. Which of the following is mismatched?
A) Penicillium — treatment of disease
B) Saccharomyces cerevisiae — for fermentation
C) Rhizobium — increases nitrogen in the soil
D) Bacillus thuringiensis — insecticide
E) algae — citric acid

E) algae — citric acid

8

Which of the following is an undesirable contaminant in wine-making?
A) Acetobacter
B) lactic acid bacteria
C) Clostridium botulinum endospores
D) Saccharomyces

A) Acetobacter

9

Commercial sterilization differs from complete sterilization in that commercial sterilization
A) kills all microorganisms.
B) kills only bacteria.
C) may result in the survival of thermophiles.
D) employs a higher temperature.
E) may result in the survival of fungal spores.

C) may result in the survival of thermophiles

10

Which of the following reactions is performed by yeast in wine-making?
A) sugar → ethanol
B) ethanol → acetic acid
C) malic acid → lactic acid
D) carbon dioxide → sucrose
E) sugar → CO2 + H2O

A) sugar → ethanol

11

Which of the following reactions makes wine less acidic, and is important for good flavor when grapes with higher acidity are used?
A) sugar → ethanol
B) ethanol → acetic acid
C) malic acid → lactic acid
D) carbon dioxide → sucrose
E) sugar → CO2 + H2O

C) malic acid → lactic acid

12

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?
A) 120 endospores
B) 10 endospores
C) 100 endospores
D) 12 endospores
E) 1 endospore

E) 1 endospore

13

All of the following are advantages of a bioreactor instead of a flask culture EXCEPT
A) larger culture volumes can be grown.
B) instrumentation for monitoring environmental conditions.
C) uniform aeration and mixing.
D) aseptic sampling.
E) None of the answers is correct; all of these are advantages of using a bioreactor instead of a flask culture

E) None of the answers is correct; all of these are advantages of using a bioreactor instead of a flask culture

14

Microbial products can be improved by all of the following EXCEPT
A) isolating new strains.
B) mutating existing strains.
C) genetically modifying strains.
D) modifying culture conditions.
E) sterilization.

E) sterilization.

15

Which of the following microorganisms is usually used in the fermentation of alcoholic beverages?
A) Propionobacterium
B) Lactobacillus
C) Rhizopus
D) Saccharomyces
E) Penicillium

D) Saccharomyces

16

All of the following are true of irradiation methods used for food preservation and sterilization EXCEPT
A) they prolong shelf-life of fruits and vegetables.
B) residual radioactivity is left behind on many foods.
C) ionizing radiation such as X rays or gamma rays is used.
D) they are used for the sterilization of many spices.
E) they greatly reduce the number of pathogens present in meats and poultry.

B) residual radioactivity is left behind on many foods.

17

All of the following are industrial products produced by microbes EXCEPT
A) amino acids in food supplements.
B) antibiotics.
C) industrial enzymes.
D) uranium.
E) vitamin B12 and riboflavin.

D) uranium.

18

All of the following are industrial products produced using microbial fermentations EXCEPT
A) aspartic acid.
B) citric acid.
C) glutamic acid.
D) riboflavin.
E) saccharin.

E) saccharin

19

All of the following foods are produced using microbial fermentations EXCEPT
A) sauerkraut.
B)ketchup.
C) sour cream.
D) yogurt.
E) coffee.

B) ketchup

20

Which of the following microbes produces a natural biopesticide?
A) Penicillium chryssogenum
B) Saccharomyces cerevisiae
C) Bacillus thuringiensis
D) Lactobacillus buggaricus
E) Thiobacillus ferroxidans

C) Bacillus thuringiensis

21

Biomass is a renewable energy source derived from the organic matter produced by living organisms. All of the following are sources of biomass EXCEPT
A) oxidation of metals.
B) crops.
C) bacteria.
D) landfill sites.
E) algae.

A) oxidation of metals.

22

All of the following are industrial enzymes made by microbial fermentations EXCEPT
A) glucose isomerase.
B) rennin.
C) proteases.
D) amylases.
E) vitamin C.

E) vitamin C.

23

What process does yeast use to produce ethanol for automobile fuel from corn?
A) anaerobic respiration
B) fermentation
C) the Krebs cycle
D) oxidation
E) photosynthesis

B) fermentation

24

The following steps are required for making cheese. What is the second step, which helps to provide the characteristic flavors and aromas of the cheese?
A) enzymatic coagulation of milk
B) fermentation of curd
C) inoculation with lactic acid bacteria
D) inoculation with Penicillium
E) separation of curds and whey

C) inoculation with lactic acid bacteria

25

As cheese ages, it gets
A) more acidic.
B) more whey.
C) more protein.
D) saltier.
E) more alcoholic.

A) more acidic.

26

Acidithiobacillus ferrooxidans is used for the recovery of ________ from ore.
A) sulfur
B) copper
C) iron
D) sulfuric acid
E) gold

B) copper

27

What role do lactic acid bacteria play in cheese production?
A) curd formation
B) production of holes in Swiss cheese
C) ripening the cheese
D) providing characteristic flavor and smell
E) Lactic acid bacteria carry out each of these roles in cheese production.

E) Lactic acid bacteria carry out each of these roles in cheese production.

28

You are growing Bacillus subtilis, an aerobic bacterium that can also carry out fermentation when required, in a bioreactor and notice that the growth rate has slowed and the pH has decreased. You suspect the bacteria are
A) using the Krebs cycle.
B) fermenting.
C) photosynthesizing.
D) using proteins.
E) dead.

B) fermenting

29

You are growing Bacillus subtilis, an aerobic bacterium that can also carry out fermentation when required, in a bioreactor and notice that the growth rate has slowed and the pH has decreased. What could you add?
A) glucose
B) lactose
C) peptides
D) oxygen
E) lactic acid

E) lactic acid

30

Aseptic packaging utilizes which of the following to sterilize laminated paper or plastic prior to filling with food?
A) hot HCl solution
B) gamma radiation
C) hot hydrogen peroxide solution
D) X rays
E) autoclave

C) hot hydrogen peroxide solution

31

All of the following are uses for ionizing or ultraviolet radiation EXCEPT
A) heating cold food.
B) sterilizing spices.
C) inactivation of Trichinella larvae.
D) killing of insect eggs and larva.
E) prevention of sprouting.

A) heating cold food.

32

Canning preserves food
A) through use of aseptic packaging.
B) by exposure to chemicals.
C) by exposure to high heat.
D) by exposure to radiation.
E) by exposure to high pH.

C) by exposure to high heat.

33

Microorganisms themselves are commercial products. Which of the following microbes is available as a product sold in retail stores?
A) Bacillus thuringiensis
B) Lactobacillus
C) Rhizobium
D) Saccharomyces
E) All of these organisms can be found in various commercial products.

E) All of these organisms can be found in various commercial product

34

Canning works to preserve foods through
A) creation of an anaerobic environment.
B) creation of an anaerobic environment and exposure to high heat.
C) exposure to high heat.
D) mutation of bacterial DNA.
E) increasing pH.

B) creation of an anaerobic environment and exposure to high heat.

35

Aseptic packaging (where the packaging itself is rendered sterile) helps to preserve foods through
A) creation of an anaerobic environment in the packaging.
B) creation of an anaerobic environment in the packaging and exposure of the packaging to high heat.
C) exposure of the packaging to high heat.
D) mutation of bacterial DNA by exposure to the packaging material.
E) increasing pH in the food contained in the packaging.

C) exposure of the packaging to high heat.

36

Radiation works to preserve foods through
A) creation of an anaerobic environment.
B) creation of an anaerobic environment and high heat.
C) exposure to high heat.
D) lethal mutation of bacterial DNA.
E) increasing pH.

D) lethal mutation of bacterial DNA.

37

All of the following are reasons for utilizing algae for biofuel production EXCEPT
A) they do not take up land needed for food production.
B) they produce more energy per acre than corn.
C) their main requirement is abundant light.
D) they can utilize agriculturally poor land.
E) they produce a nondegradable waste product.

E) they produce a nondegradable waste product.

38

What will be produced if wine is aerated and inoculated with bacteria of the genera Acetobacter and Gluconobacter?
A) ethanol + CO2
B) CO2 + H2O
C) CH4
D) acetic acid
E) None of the answers is correct.

D) acetic acid

39

Bioreactors are widely used for industrial fermentation. Which of the following conditions must be closely monitored for optimal fermentation?
A) temperature
B) oxygen levels
C) pH
D) both temperature and pH
E) temperature, pH, and oxygen levels

E) temperature, pH, and oxygen levels

40

Xanthan used in household products is produced by bacteria
A) that were genetically modified.
B) that were irradiated to mutate them.
C) selected for their ability to utilize lactose rather than glucose.
D) that are plant pathogens.
E) selected for their ability to utilize lactose rather than glucose and

E) selected for their ability to utilize lactose rather than glucose and that are plant pathogens.