Question

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Lecture exercise 1 & laboratory exercises (1 pt. cach, 40 pts. total) 31. What was the question that Fleming asked in the case study? a. Why were there clear areas around the mold? c. Can bacteria grow rapidly on agar plates? b. Do molds produce a chemical tha us produce a chemical that kills bacteria? De hacteria produce a chemical that kills molds? e not having a control, Fleming was able to support his hypothesis because of which evidence he observed from the experiment he performed? a. A chemical was successfully isolated from the broth where the mold grow. b. Bacteria always died when combined with the broth where the mold grow. c. There was always a clear area around the mold whenever he grew bacteria on an agar plate. d. The bacteria kept killing the mold every time they were mixed together. 33. Which set up is the most appropriate control to test the hypothesis that only the particular green mold (that contaminated his plates) produces a chemical that kills bacteria? a. Grow a bacterial culture with no additional broth poured into it. b. Pour sterile nutrient broth into a growing bacterial culture. c. Grow a different mold in a nutrient broth, remove the mold & add the broth into a growing bacterial culture. d. Grow the green mold in a broth, remove the mold & add the nutrient broth into a growing bacterial culture. was discovered and developed as a result of Fleming's investigation of the mold that contaminated his bacterial cultures. a. Penicillin b. Staphylococcus c. Penicillium d . Anti-fungal cream e. Fever relievers 35. The statement "Like dissolves like." refers to which characteristic of molecules? a. size b. shape c . polarity d. complexity Interpretation of observed results 36. Potassium permanganate (KMnO4) is polar 37. Vegetable oil is nonpolar. 38. Detergent is amphipathic. Observed evidence a. purple color of water (bottom) layer b. yellow color of oil layer on top, clear layer (water) below c. water, oil and KMnO, altogether turned uniformly purple after mixing with detergent 19. Which characteristic of KMnOs made it dissolve in water but not in oil? its relatively small size b. it is polar c . its heavy mass d. being purple in color 40. An amphipathic substance a. has heavy region as well as a light region c. contains both c. contains both the positive & negative charge b. is an oily liquid d. contains polar and nonpolar regions 41. Which of the following solutions is neither an acid nor base? cleaner pH-13 b. baking soda pH-9 c. milk pH-7 d. vinegar pH 4 e gastric fluid pll-2 When similar concentration and volume of HCl and NaOH solutions are combined does not change b. crystals forms c. pH-7 d. water evaporates e. an explosion occurs Which prediction is appropriate? If a solution is acidic, then we predict concentration is less than that of water c. the solution would be cloudy ' is being released into the solution d. its pH is greater than 7 h a. 2X more 44. A substance with pH - 9 has Hr than the substance with pH = 11. b. half the amount of c. 100X more d. 1/100 the amount of If the pH of a solution is 3. What will be its pH if it was diluted with water? 5.5 c. 7 0.9

Answer 1

31.b Do molds produce a substance that kills bacteria thus making the zone around them clear?

32. a.A chemical was successfully isolated from the broth where the mold grew.

(He had evidences such as the clear zone on plates with mold and the broth of mold illing bacteria but these experiments need a control to be verified.)

33. b. Pour sterile nutrient broth into a growing bacterial culture

(growing another mold and adding its broth would serve as negative control)

34 a. Penicillin

35. c.Polarity

39.b it is polar

40.d contains both polar and non polar regions

41. c. Milk pH =7

42.c.pH=7

43.c. H+ is being released into the solution

44.c. 100X more as pH is the negative log of concentration of H +

45.b. 5 as with dilution with water H+ concentration decreases so it cannot be 1, acidic solution doesn't become alkaline or neutral when diluted as water with which it is diluted is not alkaline.