MCB 3020 Test 2 Spring 01 Name__________________________

1. One hundred bacteria multiply into 10,000,000 bacteria in 100 minutes. What is the generation time?

a. 10 min b. 0.1 hr c. 0.6 hr d. 0.2 hr e. 20 minutes

2. Eighty bacteria per mL contaminate a donut. The volume of the donut is approximately 7mL. The generation time is 20 minutes. After 8 hours, what was the concentration of bacteria i.e number per mL?

a. 80 x 10 x 28 b. 80 x 1024 c. 80 x 224 d. 2 x 2024 e. 20 x 224 x 7 ab. 80 x 220 ac. 80 x 28 ad. 80 x 224 x 7

3. Beginning with a bacterial culture containing 1 organisms per mL, how long would it be before there were 1,000,000 organisms per mL, assuming a generation time of 30 minutes.

a. 250 min b. 1550 min c. 600 min d. 700 min e. 1300 min

4. What is n (the number of generations) when 105 cells multiply into 1011 in 12 hours.

a. (log 105 - log 1011)/ 0.301

b. (log 1011 - log 105) / .301

c. 0.301 / 11-5

d. 0.301 (12hr) / (11 -5)

e. .301 (11-5) / 12

5. Which of previous question’s answers is the generation time g? (Use # 4 answers)

6. Calculate the growth rate constant k, if the generation time is 10 min.?(Careful with hr & min.)

a. 10 x n doublings per minuteb. 1/10 doublings per hourc. 4 doublings per hourd. 6 doublings per hour e. 2 doublings per hour

7. Six cells multiply into 96 cells in 60 minutes. What is the generation time?a. 20 minutes b. 60 minutes c. 30 minutes d. .301(90 min) / log 96 e. 15 min

8. Which of the following does not contain a high energy bond?

9. What method is used to produce only surface colonies in the viable plate count method?

a. spread plate b. block plate c. streak plate d. pour plate e. a, c

10. The redox potential of the redox pair that accepts electrons is -.20 and that of the redox pair losing electrons is -.8. If 4 equivalents of electrons are transferred, what is the free energy change? Write answer with correct signs in right places.

a. -(4)(23)(-0.6) kcalb. -(4)(46)(-0.6) caloriesc. -(4)(23)(1.0) kcald. (4)(23)(1.0) caloriese. -(4)(23)(0.6)kcal

11. Choose the best energy source?a. H2 b. SO4

-2 c. NO2- d. Fe+3 e. b,c

12. For the reaction, monosaccharide + monosaccharide disaccharide, a. ^G is negativeb. reaction procedes if the subunits are first activated and then water is removedc. the amino acid subunits spontaneously are linked together into the dipeptide d. the reaction is an example of phase III or assemblye. c,d

13. The water activity a. is the ratio of the vapor pressure of pure water to the vapor pressure above the

solutionb. that is needed for fungi is .995c. decreases as the solute concentration increasesd. is the negative log {H+}e. is the solute concentration of the solution over the solute concentration of pure

water

14. Which of the following produces a lag phase? a. cells growing on glucose exponentially are used to inoculate a lactose mediumb. exponential culture inoculated into a fresh medium of same chemical

compositionc. old or stationary culture inoculated into a fresh medium?d. cells growing on lactose are inoculated into a fresh lactose mediume. a,c bc. b,c bd. b,d

Answers for 15-17 a. fermentation b. aerobic respiration c. anaerobic respiration d. photoorganotroph e. chemolithotroph

15. Fe+2 is used as an energy source and CO2 as a carbon source 16. Substrate level phosphorylation as only mechanism of ATP synthesis17. The biological oxidation in which CO2 serves as terminal electron acceptor.

18. In doing a microscopic count, 0.02mL of a bacterial suspension was spread over a circle of diameter 6 cm. A stage micrometer was used to measure the diameter of the microscopic field as 1.0 mm. The average number of bacteria per microscopic field was 75. What is the average number of bacteria per mL in the original suspension?

a. 75 x (.02mL) x (3cm)2/(.5mm)2

b. (75) x (60mm)2/(1.0mm)2

c. (6cm)2/(1.0mm)2 / .02mLd. (75) x (30mm)2 / (.5mm)2 x 1/.02mLe. (30mm)2 / (.5mm)2 x 1/.02mL

19. In the Krebb’s cyclea. 8 ATP are produced under aerobic conditionsb. all the ATP is made by oxidative phosphorylationc. Acetyl COASH reacts with citrate to form oxaloacetated. None of the intermediates is used for biosynthesise. None of above

20. Which of the following terms is best used to describe the type of microorganismgrowing in the thioglycollate medium to the right?

a. Obligate psychrophileb. Facultative Anaerobec. Facultative Aerobed. Microaerophillice. halophile

21. According to the Beer-Lambert Lawa. an absorbance of zero is 0% transmissionb. the absorbance is inversely proportional to concentration c. a 100% transmission equals an absorbance of 1d. Absorbance equals 2- log %Te. c,d

22. The buildup of toxic metabolic products and the depletion of nutrients leads toa. a sharper slope in growth curve

b. an exponential phase with + kc. a death phase with k = 0d. a stationary phase with k = maximume. a growth rate constant of zero

23. Which of the following is correct?a. a psychrophile grows at 60oCb. between the minimum and optimum temperatures growth increases because of

increasing collisions between moleculesc. between the optimum and maximum temperatures the growth increases

because of increasing collisions between moleculesd. above the maximum temperature all cells diee. above the minimum temperature, proteins are denatured

24. Superoxidea. is harmful to aerobes for they lack enzymes to destroy this compoundb. is singlet oxygenc. is superaniond. is hydroxyl free radicale. is destroyed in aerobes by a dismutase enzyme

25. The ATPase enzymea. is located in the cell wall in procaryotesb. is part of Mendelsohn’s chemiosmotic theoryc. has an F0

that allows protons to move outside cell to synthesize ATPd. has an F0 that catalyzes synthesis of ATPe. synthesizes ATP when protons move into the cell

26. All of the following are related to the speed of the reaction except:a. catalystb. equilibrium constantc. energy of activationd. enzymese. a,d

27. Which of the following is the active form of the enzymea. apoenzymeb. apoenzyme combined with the holoenzymec. holoenzymed. coenzyme combined with the holoenzymee. b,c

28. Which of the following is correcta. the mechanism of ATP synthesis in Aerobic Respiration includes only

oxidative phosphorylationb. the product of Krebb’s cycle responsible for producing the most ATP alpha-

ketoglutaric acid

c. Fermentation is faster than Aerobic Respirationd. An example of anaerobic respiration is NADH + H+ converting Pyruvate

Lactatee. b,c

29. The conversion of a Carbon skeleton to a pyrimidine base that reacts with a ribose-phosphate to make a nucleotide is what phase of metabolism?

a. Class I b. Class IIIc. fueling d. biosynthesis e. assembly

30. Which metabolism phase includes the combining of lipids and proteins to make the membrane of the cell? (use previous question’s answers)?

31-32. In the following reactions: (be careful and watch directions of the two half reactions)

A. e- + Y Y-

B. X X+1 + e-

31. Which of the above is the oxidizing agent?a. X+1 b. X c. Y- d. Y

32. In which reaction is the reactant being converted to a more reduced product?a. A b. B c. both A & B d. neither A or B

33. What provides 8 net ATP for procaryotes? EM =Embden Meyerhoff (Glycolysis)a. EM pathway in fermentation TCA= Krebb’s Cycleb. ATPase action from NADH + H+ c. aerobic respiration (EM + TCA)d. EM pathway in aerobic respiration e. electron transfer reactions in TCA cycle

34. Oxidative phosphorylationa. is the direct synthesis of ATP in a chemical reactionb. is produced from a high energy phosphate bondc. is electron transfer chain mediated synthesis of ATP caused by protonsd. is oxidation of glucose to pyruvatee. a,b

35. Which graph is correct?

a. A b. B c. C d. none e. all

The following are redox pairs:36-37. I. Fe+3/Fe+2 Eo’ = +.70

II. Z/Z- Eo’ = -0.75III. 2H+/H2 E0’ = -0.42

36. When comparing the above redox pairs, the greatest amount of energy would be produced when:a. H2 donates electrons to Zb. H2 donates electrons to Fe+3

c. Z- donates electrons to H+

d. Fe+3 donates electrons to H+

e. Z- donates electrons to Fe+3

ab Z- donates electrons to Fe+2

ac Z donates electrons to Fe+3

ad. Z donates electrons to Fe+2

ae. H+ donates electrons to Fe+3

bc H+ donates electrons to Z-

bd. H+ donates electrons to Zbe. H2 donates electrons to Z-

cd. Z donates electrons to H2

ce. Fe+2 donates electrons to Z

37. If no Fe+3/Fe+2 redox pair members were available, what would be the direction of electron flow using other two redox pairs? Use previous question answers.

38. Glucose is oxidized via EM pathway to pyruvate. Pyruvate is converted through a series of reactions to propionic acid. One of the intermediates leading to propionic acid is reduced by NADH + H+ (made earlier in EM pathway).

a. this is an example of anaerobic respirationb. this is an example of oxidative phosphorylationc. this is chemolithotrophic metatbolismd. aerobic respiration for oxygen is present and electron transfer to the intermediate

occurse. this is fermentation

39. Most biological oxidations (WRITE ALL CORRECT ANSWERS)a. are exergonic and produce energy b. are free energy change negative c. occur by the removal of two hydrogens d. are direct reactions with oxygen e. are non spontaneous in thermodynamic sense

40. How would you label plate D?

a. 10-4 b. 10-5 c. 10-6 d. 10-7 e. 10-8 ab. 10-9 ac. 10-10

41. As the concentration of a. solute in solution increases, plasmolysis occursb. H+ ion increases, the pH increasesc. salt in solution increases, the aw value gets smallerd. b, ce. a, cab a,babc. a,b,c

42. Which of the curves represents a osmophile?

a. A b. B c. C d. D e. E

43. The reaction , glyceraldehyde 3-phosphate + NAD+ + Pi 1,3 diphosphoglycerate + NADH + H+ is the most important reaction of the EM pathway, and

a. it is the only oxidation in EM pathwayb. it produces a reduced coenzymec. it produces a high energy phosphate

d. it is exergonic and ^G negativee. all of above are trueab. a,bac. a,cabd. a,b,d

Diagram Below: Viable Plate Count Method use for questions 44-45.

44. What is the concentration in the 4.8 mL dilution blank?a) 40 x (1/.25) x (100)b) 40 x (1/.25) x (100) x (8)c) 40 x (1/.25) x (100) x (8) x (33)d) 312 x (1/.1) x (8)e) 312 x (1/.1) x (8) x (33)

45. What is concentration in the original suspension?a) 4.22 x 105 bac/mlb) 4.22 x 106 bac/mlc) 1.28 x 105 bac/mld) 1.28 x 106 bac/mle) 1.05 x 106 bac/ml

46-50. Write the answer a for all five questions for credit.

Answer Key:1 b2 c3 c4 d5 d6 d7 e8 b9 a10 e11 a12 b13 c14 e15 e16 a17 c

18 d19 e20 d21 d22 e23 b24 e25 e26 b27 c28 c29 d30 e31 d32 a33 d34 c

35 c36 e37 c38 e39 a,b,c40 e41 e42 d43 e44 b45 b46 a47 a48 a49 a50 a