3. Write the simplified for glycolysis (include electron transporters)

Transcription

1 Food Science Fermentation (Division C) 1. What two cultures are used to produce yogurt? a. Lactobacillus bulgaricus and Pediococcus pentasaceous b. Lactobacillus plantarum and Streptococcus thermophilus c. Lactobacillus bulgaricus and Streptococcus thermophilus d. Lactococcus lactis and Bifidobacter bifidum 2. A microorganism that can grow at moderate but not high temperatures is called: a. Psychrotrophic b. Mesophilic c. Halophilic d. Thermophilic 3. Write the simplified for glycolysis (include electron transporters) 4. What alcoholic beverage undergoes two fermentation steps? a. Champagne b. Wine c. Beer d. Whiskey 5. An enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule is called a what? a. Transferase b. Oxidase c. Kinase d. Lipase 6. The small flavor molecules produced during fermentations are generally: a. Low molecular weight b. Aldehydes and ketones c. Byproducts of fermentation d. All of the above 7. Which of the following is not a lactic acid bacterium? a. Lactococcus lactis b. Bacillus cereus c. Lactobacillus rhamnosus d. Leuconostoc mesenteroides

2 8. Which of the following is not an intermediate in the citric acid cycle? a. Oxaloacetate b. Acetyl- coa c. α- ketoglutarate d. Fumarate 9. Describe the difference between homolactic and heterolactic fermentation, and provide an example of a food produced by each. 10. Explain mixed fermentation. Provide an example of a food. 11. True or false: amylases ferment starch into maltose. 12. Which has more energy, ATP or ADP? 13. What is the scientific name for baker s yeast? a. Saccharomyces cerevisiae b. Acetobacter xylinum c. Lactobacillus bulgaricus d. Actinomyces odontolyticus 14. Xanthomonas campestris produces a fermentation product called, commonly used as a thickening agent in salad dressings. a. Carrageenan b. Xanthan gum c. Pectin d. Gelatin 15. What acid in milk is fermented by bacteria? a. Lactic acid b. Malic acid c. Citric acid d. Oxalic acid 16. This class of microorganism can tolerate small amounts of oxygen. a. Microaerophiles b. Halophiles c. Anaerobes d. Facultative aerobes

3 17. What bacterium is responsible for the holes in Swiss cheese? a. Lactococcus lactis b. Penicillium roquefortii c. Micrococcus luteus d. Propionobacterium shermanii 18. What bacterium is responsible for the late- blowing defect in aged, ripened cheeses? a. Clostridium tyrobutyricum b. Clostridium botulinum c. Clostridium difficile d. Clostridium perfringens 19. Under what conditions will molds and yeasts out- compete bacteria? a. Low ph (<4) b. High ph (>9) c. Low water activity (0.6 < Aw < 0.8) d. All of the above e. None of the above 20. The enzyme that hydrolyzes lactose into glucose and galactose is called a. β- galactosidase b. β- glucosidase c. Lactose permease d. Galacturonidase 21. What is the final electron receptor in oxidative phosphorylation? a. Water b. Oxygen c. Carbon dioxide d. ATP 22. What does ATP stand for? 23. True or false: oxidative phosphorylation requires a proton gradient. 24. Aspergillus flavus and Aspergillus parasiticus produce liver toxins known as what? a. Enterotoxins b. Aflatoxins c. Ergot alkaloids d. Ochratoxins 25. The acids that are produced during the production of sourdough bread are: and acids.

4 26. Sake is made using what cereal grain? a. Corn b. Wheat c. Rice d. Barley 27. What is this the chemical structure for? 28. In beer production, how are ale and lager yeasts different? a. Ale yeasts ferment on the top, while lager ferment on the bottom of the barrel. b. Ale yeasts ferment on the bottom, while lager ferment on the top of the barrel. c. The strains of yeast that are used are different. d. There is no difference. 29. Kumis is a fermented dairy beverage made from the milk of what animal? a. Cow b. Goat c. Horse d. Sheep 30. How many ATP are produced during glycolysis? a. 2 b. 4 c. 34 d Why are lactic bacteria sometimes called self- limiting? 32. In the final step of lactic acid fermentation, lactate dehydrogenase reduces WHAT glycolytic intermediate? a. Lactose b. Pyruvate c. Acetyl- coa d. NAD What does CFU stand for?

5 Food Science C Fermentation II 1. What causes bread dough to rise? a. O 2 produced by yeasts b. CO 2 produced by yeasts c. CO 2 produced by lactic acid bacteria d. O 2 produced by lactic acid bacteria 2. What is the substrate for maltase? a. Cellulose b. Starch c. Maltose d. Glucose 3. Kinases transfer a group from ATP to other molecules. 4. Lactobacillus is used in vegetable fermentations including kimchi and sauerkraut. 5. This genus of lactic acid bacteria is used for dried, fermented sausages and produces the holes in Swiss cheeses a. Lactobacillus b. Lactococcus c. Pediococcus d. Streptococcus 6. What class of microorganisms does not ferment? a. Molds b. Yeasts c. Bacteria d. None of the above 7. is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy 8. is the set of metabolic pathways that construct molecules from smaller units. 9. Which of the following is not another name for the Citric Acid Cycle a. The TCA cycle b. The Pentose Phosphate Pathway c. The Krebs cycle d. None of the above 10. Proteases break down into their monomeric units, acids.

6 11. The pentose phosphate pathway generates pentose sugars and what electron transporter? a. NADPH b. NADH c. FADH 2 d. NAD What is the Co in acetyl Co- A short for? a. Cofactor b. Coenzyme c. Cobalt d. Coreactor 13. The gelatinous mass that contains the SCOBY used for kombucha fermentation is commonly called what? a. The father b. The mother c. The daughter d. The SCOBY it does not have another name 14. How are probiotics different from starter bacteria in yogurt production? 15. Pyruvate dehydrogenase decarboxylates pyruvate to yield which important molecule used in the citric acid cycle? a. Pyruvic acid b. Oxaloacetate c. Acetyl- coa d. Succinyl- coa 16. Natto is a fermented food made from which of the following: a. Soybeans b. Cabbage c. Rice d. Fish 17. Aspergillus is a genus of: a. Mold b. Yeast c. Bacteria 18. Which is the oxidized form: NAD + or NADH?

7 19. What causes the gel structure of yogurts to form? a. Protein denaturation as a result of heating b. Exopolysaccharides produced by bacteria c. Protein denaturation as a result of ph reduction d. Bacterially produced polysaccharides that gel 20. True or false: products with a ph below 4.6 are considered high acid. 21. Which enzyme is not required for the citric acid cycle? a. α- ketoglutarate dehydrogenase b. Succinic dehydrogenase c. Citrate synthase d. Phosphofructokinase 22. During glycolysis, Fructose- 1,6- bisphosphate is converted to two products. One of these products can be converted to the other using triose phosphate isomerase. Which product is needed to continue glycolysis? a. Dihydroxyacetone phosphate b. Glyceraldehyde- 3- phosphate c. 3- phosphoglycerate d. 1,3- bisphosphoglycerate 23. Complete the reaction in glycolysis: 1,3- bisphosphoglycerate 3- phosphoglycerate Enzyme: 24. During the production of sauerkraut, why are coliforms inhibited? a. The salt addition b. The acid produced c. They require a simple sugar source d. Coliforms are not inhibited 25. True or false: Miso is a mixed fermentation. 26. Which is more easily fermented, lactose or glucose? Why?

8 27. Home- canning of vegetable products can be very dangerous because this bacterium is not destroyed during boiling. a. Clostridium tyrobutyricum b. Clostridium botulinum c. Clostridium dificille d. Clostridium perfringens 28. Lassi is a fermented dairy beverage from what country? a. China b. Brazil c. Ireland d. India 29. True or false: oils can be fermented. 30. What is commonly known as fruit sugar? a. Lactose b. Glucose c. Fructose d. Stacchyose 31. How are ale yeasts and lager yeasts different? a. They are different strains of S. cerevisiae b. Ale yeasts ferment at a higher temperature c. The substrates for the yeasts are different d. They are not different 32. Which bacteria in yogurt production is more thermotolerant? 33. Three flasks are filled with baker s yeast and a white crystalline substance. A little bit of warm water is added to both and a balloon is placed at the neck of the flask. Balloon A inflates completely after one hour, Balloon B does not inflate at all and Balloon C inflates partially. Match the substrates to the balloon. Balloon A Balloon B Balloon C Salt Lactose Glucose 34. What is the necessary ph to inhibit C. botulinum? a. 2.5 b. 4.6 c. 7.0 d. 9.2

9 Food Science Fermentation III 1. What does SCOBY stand for, and what is one product that uses a SCOBY to begin fermentation? 2. Fermented foods are shelf- stable if they are below ph 4.6 because this ph will inhibit the growth of what potentially fatal bacterium? a. Staphylococcus aureus b. Clostridium botulinum c. Clostridium perfringens d. Bacillus cereus 3. Which enzyme is not required for the citric acid cycle? a. Succinic dehydrogenase b. Citrate synthase c. Phosphofructokinase d. α- ketoglutarate dehydrogenase 4. What acid in milk is fermented by bacteria? a. Lactic acid b. Citrate c. Lactose d. Oxaloacetate 5. True or false: glycolysis requires oxygen. 6. Triose phosphate isomerase is needed during glycolysis to convert what compound into another compound that can continue in the glycolytic reactions? a. Glucose- 6- phosphate b. Glyceraldehyde- 3- phosphate c. Dihydroxyacetone phosphate d. 3- phosophoglycerate 7. β- oxidation of fatty acids can be used to produce what compound, important for the Krebs cycle? a. Oxaloacetate b. Acetyl- coa c. NADH d. FADH 2 8. True or false: Quick breads are made from a yeasted dough.

10 9. Choose the correct words to complete this sentence: fermenters are used to produce acid in yogurt, and fermenters are used for flavor production. a. Homolactic/homolactic b. Heterolactic/homolactic c. Homolactic/heterolactic d. Heterolactic/heterolactic 10. Foods that are produced using two different microorganisms are called what? a. Wild fermentations b. Mixed fermentations c. Controlled fermentations d. Fermented foods, there is no special terminology 11. Microbes that are added to fermented foods solely for flavor production are called what? a. Adjuncts b. Starter cultures c. Wild fermenters d. Cariogenic 12. The starter cultures used to produce yogurt are a. Mesophilic b. Thermophilic c. Psychrotrophic d. Halophilic 13. Sauerkraut is produced by adding 2.3% salt to cabbage and allowing it to ferment at room temperature. What might happen if too little salt is added? 14. Which byproduct of fermentation is important for the flavor of buttermilk, and is used commercially as flavoring for movie theatre popcorn. a. Butyrate b. Acetaldehyde c. Malate d. Diacetyl 15. media contains certain chemicals/compounds that prevent the growth of certain microorganisms while allowing others to grow a. Selective b. Communal c. Differential d. Facultative

11 16. Which is the oxidized form, FAD + or FADH 2? FAD What are kefir grains? 18. You perform a Gram stain on the bacteria isolated from a yogurt sample, and notice three types of bacteria under the microscope. Type A exists as small purple spheres, Type B is large purple rods, and Type C is small pink rods. What would you conclude about the bacteria? a. Type A is a contaminant b. Type B is a contaminant c. Type C is a contaminant d. There is no contamination How do you know? 19. Which thickening agent, common in salad dressings and sometimes ice creams, is produced by fermentation? a. Xanthan gum b. Carrageenan c. Guar gum d. Gelatin 20. What compound is produced by C. tyrobutyricum, and is responsible for the late- blowing defect in certain aged cheeses? a. O 2 b. H 2 O c. CO 2 d. Ethanol 21. ATP is produced during which two steps in glycolysis? a. 1 and 3 b. 1 and 7 c. 7 and 3 d. 7 and What is the number 1 export of Wisconsin, and a fermented food?

12 23. Identify the following chemical structures: a. c. b. d. 24. The agar you are using to select for fermentative bacteria contains lactose and a phenol red indicator. When you first plate your sample, the agar is red. After 24 hours of incubation, the agar surrounding the colonies has turned yellow. Why? a. The bacteria ferment lactose and the ph drop has caused the indicator to turn yellow b. The bacteria ferment the phenol red, turning it yellow c. The bacteria do not ferment, the agar would have turned yellow anyway d. The bacteria cannot ferment lactose and the yellow is from the dead cells 25. Why is it important to make sure fermented products have little oxygen in the container? a. It will prevent the growth of yeast b. It will prevent further fermentation c. It will destroy enzymes d. It will prevent the growth of molds 26. Natto, miso, and tempeh are products made from fermentation of what product? a. Rice b. Wheat c. Soybeans d. Fish 27. Enzymes that catalyze the transfer of a phosphate group to a molecule are called what? a. Kinases b. Transferases c. Oxidoreductases d. Catalases 28. True or false: the starter bacteria used to produce yogurt are considered probiotics.

13 Food Science Fermentation (Division C) 1. What two cultures are used to produce yogurt? a. Lactobacillus bulgaricus and Pediococcus pentasaceous b. Lactobacillus plantarum and Streptococcus thermophilus c. Lactobacillus bulgaricus and Streptococcus thermophilus d. Lactococcus lactis and Bifidobacter bifidum 2. A microorganism that can grow at moderate but not high temperatures is called: a. Psychrotrophic b. Mesophilic c. Halophilic d. Thermophilic 3. Write the simplified for glycolysis (include electron transporters) Glucose (C 6 H 12 O 6 ) + 2NAD + +2ADP +2Pi! 2Pyruvate (C 3 H 4 O 3 ) + 2NADH + 2ATP + 2H + +2H 2 O 4. What alcoholic beverage undergoes two fermentation steps? a. Champagne b. Wine c. Beer d. Whiskey 5. An enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule is called a what? a. Transferase b. Oxidase c. Kinase d. Lipase 6. The small flavor molecules produced during fermentations are generally: a. Low molecular weight b. Aldehydes and ketones c. Byproducts of fermentation d. All of the above 7. Which of the following is not a lactic acid bacterium? a. Lactococcus lactis b. Bacillus cereus c. Lactobacillus rhamnosus d. Leuconostoc mesenteroides

14 8. Which of the following is not an intermediate in the citric acid cycle? a. Oxaloacetate b. Acetyl- coa c. α- ketoglutarate d. Fumarate 9. Describe the difference between homolactic and heterolactic fermentation, and provide an example of a food produced by each. Homolactic: only produce lactic acid (yogurt) Heterolactic: produce lactic acid, ethanol, and CO 2 (kimchi) 10. Explain mixed fermentation. Provide an example of a food. Two kinds of microorganisms are present. Sourdough bread, blue cheese 11. True or false: amylases ferment starch into maltose. 12. Which has more energy, ATP or ADP? _ATP_ 13. What is the scientific name for baker s yeast? a. Saccharomyces cerevisiae b. Acetobacter xylinum c. Lactobacillus bulgaricus d. Actinomyces odontolyticus 14. Xanthomonas campestris produces a fermentation product called, commonly used as a thickening agent in salad dressings. a. Carrageenan b. Xanthan gum c. Pectin d. Gelatin 15. What acid in milk is fermented by bacteria? a. Lactic acid b. Malic acid c. Citric acid d. Oxalic acid 16. This class of microorganism can tolerate small amounts of oxygen. a. Microaerophiles b. Halophiles c. Anaerobes d. Facultative aerobes

15 17. What bacterium is responsible for the holes in Swiss cheese? a. Lactococcus lactis b. Penicillium roquefortii c. Micrococcus luteus d. Propionobacterium shermanii 18. What bacterium is responsible for the late- blowing defect in aged, ripened cheeses? a. Clostridium tyrobutyricum b. Clostridium botulinum c. Clostridium difficile d. Clostridium perfringens 19. Under what conditions will molds and yeasts out- compete bacteria? a. Low ph (<4) b. High ph (>9) c. Low water activity (0.6 < Aw < 0.8) d. All of the above e. None of the above 20. The enzyme that hydrolyzes lactose into glucose and galactose is called a. β- galactosidase b. β- glucosidase c. Lactose permease d. Galacturonidase 21. What is the final electron receptor in oxidative phosphorylation? a. Water b. Oxygen c. Carbon dioxide d. ATP 22. What does ATP stand for? Adenosine triphosphate 23. True or false: oxidative phosphorylation requires a proton gradient. 24. Aspergillus flavus and Aspergillus parasiticus produce liver toxins known as what? a. Enterotoxins b. Aflatoxins c. Ergot alkaloids d. Ochratoxins 25. The acids that are produced during the production of sourdough bread are: _lactic_ and _acetic_ acids.

16 26. Sake is made using what cereal grain? a. Corn b. Wheat c. Rice d. Barley 27. What is this the chemical structure for? Lactic acid 28. In beer production, how are ale and lager yeasts different? a. Ale yeasts ferment on the top, while lager ferment on the bottom of the barrel. b. Ale yeasts ferment on the bottom, while lager ferment on the top of the barrel. c. The strains of yeast that are used are different. d. There is no difference. 29. Kumis is a fermented dairy beverage made from the milk of what animal? a. Cow b. Goat c. Horse d. Sheep 30. How many ATP are produced during glycolysis? a. 2 b. 4 c. 34 d Why are lactic bacteria sometimes called self- limiting? They produce lactic acid, but are inhibited at high concentrations of acid. 32. In the final step of lactic acid fermentation, lactate dehydrogenase reduces WHAT glycolytic intermediate? a. Lactose b. Pyruvate c. Acetyl- coa d. NAD What does CFU stand for? _Colony Forming Units_

17 Food Science C Fermentation II 1. What causes bread dough to rise? a. O 2 produced by yeasts b. CO 2 produced by yeasts c. CO 2 produced by lactic acid bacteria d. O 2 produced by lactic acid bacteria 2. What is the substrate for maltase? a. Cellulose b. Starch c. Maltose d. Glucose 3. Kinases transfer a _phosphate_ group from ATP to other molecules. 4. Lactobacillus _plantarum_ is used in vegetable fermentations including kimchi and sauerkraut. 5. This genus of lactic acid bacteria is used for dried, fermented sausages and produces the holes in Swiss cheeses a. Lactobacillus b. Lactococcus c. Pediococcus d. Streptococcus 6. What class of microorganisms does not ferment? a. Molds b. Yeasts c. Bacteria d. None of the above 7. _Catabolism_ is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy 8. _Anabolism_ is the set of metabolic pathways that construct molecules from smaller units. 9. Which of the following is not another name for the Citric Acid Cycle a. The TCA cycle b. The Pentose Phosphate Pathway c. The Krebs cycle d. None of the above 10. Proteases break down _proteins_ into their monomeric units, _amino_ acids.

18 11. The pentose phosphate pathway generates pentose sugars and what electron transporter? a. NADPH b. NADH c. FADH 2 d. NAD What is the Co in acetyl Co- A short for? a. Cofactor b. Coenzyme c. Cobalt d. Coreactor 13. The gelatinous mass that contains the SCOBY used for kombucha fermentation is commonly called what? a. The father b. The mother c. The daughter d. The SCOBY it does not have another name 14. How are probiotics different from starter bacteria in yogurt production? They are live cultures added after the initial fermentation step that remain alive during the time of consumption. 15. Pyruvate dehydrogenase decarboxylates pyruvate to yield which important molecule used in the citric acid cycle? a. Pyruvic acid b. Oxaloacetate c. Acetyl- coa d. Succinyl- coa 16. Natto is a fermented food made from which of the following: a. Soybeans b. Cabbage c. Rice d. Fish 17. Aspergillus is a genus of: a. Mold b. Yeast c. Bacteria 18. Which is the oxidized form: NAD + or NADH? _NADH_

19 19. What causes the gel structure of yogurts to form? a. Protein denaturation as a result of heating b. Exopolysaccharides produced by bacteria c. Protein denaturation as a result of ph reduction d. Bacterially produced polysaccharides that gel 20. True or false: products with a ph below 4.6 are considered high acid. _True_ 21. Which enzyme is not required for the citric acid cycle? a. α- ketoglutarate dehydrogenase b. Succinic dehydrogenase c. Citrate synthase d. Phosphofructokinase 22. During glycolysis, Fructose- 1,6- bisphosphate is converted to two products. One of these products can be converted to the other using triose phosphate isomerase. Which product is needed to continue glycolysis? a. Dihydroxyacetone phosphate b. Glyceraldehyde- 3- phosphate c. 3- phosphoglycerate d. 1,3- bisphosphoglycerate 23. Complete the reaction in glycolysis: ADP ATP 1,3- bisphosphoglycerate 3- phosphoglycerate Enzyme: _phosphoglycerate kinase_ 24. During the production of sauerkraut, why are coliforms inhibited? a. The salt addition b. The acid produced c. They require a simple sugar source d. Coliforms are not inhibited 25. True or false: Miso is a mixed fermentation. _True_ 26. Which is more easily fermented, lactose or glucose? Why? Glucose because it does not require additional enzymes to become a fermentable substrate (glucose)

20 27. Home- canning of vegetable products can be very dangerous because this bacteria is not destroyed during boiling. a. Clostridium tyrobutyricum b. Clostridium botulinum c. Clostridium dificille d. Clostridium perfringens 28. Lassi is a fermented dairy beverage from what country? a. China b. Brazil c. Ireland d. India 29. True or false: oils can be fermented. _False_ 30. What is commonly known as fruit sugar? a. Lactose b. Glucose c. Fructose d. Stacchyose 31. How are ale yeasts and lager yeasts different? a. They are different strains of S. cerevisiae b. Ale yeasts ferment at a higher temperature c. The substrates for the yeasts are different d. They are not different 32. Which bacterium in yogurt production is more thermotolerant? _S. thermophilus_ 33. Three flasks are filled with baker s yeast and a white crystalline substance. A little bit of warm water is added to both and a balloon is placed at the neck of the flask. Balloon A inflates completely after one hour, Balloon B does not inflate at all and Balloon C inflates partially. Match the substrates to the balloon. Balloon A Balloon B Balloon C Salt Lactose Glucose 34. What is the necessary ph to inhibit C. botulinum? a. 2.5 b. 4.6 c. 7.0 d. 9.2

21 Food Science Fermentation III KEY 1. What does SCOBY stand for, and what is one product that uses a SCOBY to begin fermentation? SCOBY = symbiotic colony of bacteria and yeast. Kombucha and Kefir use SCOBYs. 2. Fermented foods are shelf- stable if they are below ph 4.6 because this ph will inhibit the growth of what potentially fatal bacterium? a. Staphylococcus aureus b. Clostridium botulinum c. Clostridium perfringens d. Bacillus cereus 3. Which enzyme is not required for the citric acid cycle? a. Succinic dehydrogenase b. Citrate synthase c. Phosphofructokinase d. α- ketoglutarate dehydrogenase 4. What acid in milk is fermented by bacteria? a. Lactic acid b. Citrate c. Lactose d. Oxaloacetate 5. True or false: glycolysis requires oxygen. False 6. Triose phosphate isomerase is needed during glycolysis to convert what compound into another compound that can continue in the glycolytic reactions? a. Glucose- 6- phosphate b. Glyceraldehyde- 3- phosphate c. Dihydroxyacetone phosphate d. 3- phosophoglycerate 7. β- oxidation of fatty acids can be used to produce what compound, important for the Krebs cycle? a. Oxaloacetate b. Acetyl- coa c. NADH d. FADH 2 8. True or false: Quick breads are made from a yeasted dough. False

22 9. Choose the correct words to complete this sentence: fermenters are used to produce acid in yogurt, and fermenters are used for flavor production. a. Homolactic/homolactic b. Heterolactic/homolactic c. Homolactic/heterolactic d. Heterolactic/heterolactic 10. Foods that are produced using two different microorganisms are called what? a. Wild fermentations b. Mixed fermentations c. Controlled fermentations d. Fermented foods, there is no special terminology 11. Microbes that are added to fermented foods solely for flavor production are called what? a. Adjuncts b. Starter cultures c. Wild fermenters d. Cariogenic 12. The starter cultures used to produce yogurt are a. Mesophilic b. Thermophilic c. Psychrotrophic d. Halophilic 13. Sauerkraut is produced by adding 2.3% salt to cabbage and allowing it to ferment at room temperature. What might happen if too little salt is added? Coliforms may not be inhibited, so the LAB may not be able to compete (fermentation would not happen) and/or the food would be fermented but contaminated with coliforms. 14. Which byproduct of fermentation is important for the flavor of buttermilk, and is used commercially as flavoring for movie theatre popcorn. a. Butyrate b. Acetaldehyde c. Malate d. Diacetyl 15. media contains certain chemicals/compounds that prevent the growth of certain microorganisms while allowing others to grow a. Selective b. Communal c. Differential d. Facultative

23 16. Which is the oxidized form, FAD + or FADH 2? FAD What are kefir grains? They are colonies of bacteria and yeasts that are held together by exopolysaccharides (they kind of look like rice grains but they re really just huge masses of bacteria and yeasts) that are used to begin fermentation of kefir. 18. You perform a Gram stain on the bacteria isolated from a yogurt sample, and notice three types of bacteria under the microscope. Type A exists as small purple spheres, Type B is large purple rods, and Type C is small pink rods. What would you conclude about the bacteria? a. Type A is a contaminant b. Type B is a contaminant c. Type C is a contaminant d. There is no contamination How do you know? Type A is of Streptococcus thermophilus (a Gram- positive cocci), Type B is of Lactobacillus bulgaricus (a Gram- positive rod). Type C is likely a coliform (Gram- negative rods). 19. Which thickening agent, common in salad dressings and sometimes ice creams, is produced by fermentation? a. Xanthan gum b. Carrageenan c. Guar gum d. Gelatin 20. What compound is produced by C. tyrobutyricum, and is responsible for the late- blowing defect in certain aged cheeses? a. O 2 b. H 2 O c. CO 2 d. Ethanol 21. ATP is produced during which two steps in glycolysis? a. 1 and 3 b. 1 and 7 c. 7 and 3 d. 7 and What is the number 1 export of Wisconsin, and a fermented food? cheese

24 23. Identify the following chemical structures: a. c. Glucose Lactic acid b. d. Lactose Pyruvate 24. The agar you are using to select for fermentative bacteria contains lactose and a phenol red indicator. When you first plate your sample, the agar is red. After 24 hours of incubation, the agar surrounding the colonies has turned yellow. Why? a. The bacteria ferment lactose and the ph drop has caused the indicator to turn yellow b. The bacteria ferment the phenol red, turning it yellow c. The bacteria do not ferment, the agar would have turned yellow anyway d. The bacteria cannot ferment lactose and the yellow is from the dead cells 25. Why is it important to make sure fermented products have little oxygen in the container? a. It will prevent the growth of yeast b. It will prevent further fermentation c. It will destroy enzymes d. It will prevent the growth of molds 26. Natto, miso, and tempeh are products made from fermentation of what product? a. Rice b. Wheat c. Soybeans d. Fish 27. Enzymes that catalyze the transfer of a phosphate group to a molecule are called what? a. Kinases b. Transferases c. Oxidoreductases d. Catalases 28. True or false: the starter bacteria used to produce yogurt are considered probiotics. False