Unit 7: Mitochondria - Practice Quiz

1 What cell organelle is detected using Janus green staining in cheek epithelial cells?

2 Janus green B is mainly used as a:

3 Which cells are examined in this experiment?

4 What is the main function of mitochondria?

5 What color are mitochondria commonly observed after Janus green staining?

6 Which instrument is used to observe stained cheek cells?

7 A cheek-cell sample is usually collected by gently scraping the:

8 Why is a clean glass slide used for preparing the specimen?

9 What is placed over the specimen before microscopic observation?

10 Which cheek-cell structure is usually easiest to identify besides mitochondria?

11 Human cheek epithelial cells are classified as:

12 Which feature supports the presence of mitochondria after staining?

13 Where are mitochondria located in a cheek epithelial cell?

14 Janus green B helps identify mitochondria because it undergoes a:

15 What is the purpose of using a microscope objective with higher magnification?

16 Which microscope part is used to adjust the sharpness of the image?

17 Why should the cheek sample be observed soon after staining?

18 Which structure is absent from human cheek epithelial cells?

19 What does a negative result most directly suggest in this experiment?

20 Which safety practice is appropriate when collecting cheek cells?

21 What observation most strongly supports the presence of mitochondria in a Janus green-stained cheek epithelial cell?

22 Why is Janus green useful for demonstrating mitochondria in living cheek epithelial cells?

23 A student observes blue-green granules in the cytoplasm after applying Janus green. What is the best interpretation?

24 Which control would best help determine whether blue-green staining is caused by the cheek cells rather than the stain or slide?

25 Why should cheek cells be examined soon after collection and staining?

26 If the entire field appears intensely blue-green, which procedural problem is most likely?

27 A cheek-cell preparation shows no blue-green granules, but the cells appear damaged and colorless. Which conclusion is most appropriate?

28 Which microscope setting is most appropriate for initially locating stained cheek epithelial cells?

29 Why are mitochondria usually observed in the cytoplasm rather than inside the nucleus in this experiment?

30 What is the main purpose of gently scraping the inside of the cheek before preparing the slide?

31 A student sees several stained particles outside the cells as well as granules inside them. What should the student do before identifying the particles as mitochondria?

32 If the coverslip is pressed too firmly during slide preparation, what observation may result?

33 Why should the Janus green solution be applied evenly across the specimen?

34 Which finding would most strongly suggest that the stain was not functioning properly?

35 Why is a cheek epithelial cell suitable for this demonstration even though it is not highly specialized for energy production?

36 A student concludes that cells with more visible granules must always have more mitochondria. What is the best correction?

37 Which change would most likely improve a preparation with a very high background and poorly defined cells?

38 What does the blue-green color of Janus green primarily indicate in this procedure?

39 A student observes a blue-green region only near the edge of a cell. Which explanation is most reasonable before repeating the experiment?

40 Which result would provide the strongest evidence that the observation is reproducible?

41 A cheek-cell preparation shows discrete blue-green granules after Janus green staining, while an unstained preparation shows no granules. Which conclusion is most justified?

42 A student observes that freshly prepared cheek cells stain blue-green, but cells left covered on the slide for 20 minutes become nearly colorless. What is the best interpretation?

43 Which control would most directly test whether blue-green staining depends on metabolically active mitochondria rather than nonspecific dye deposition?

44 A slide contains intensely blue-green material in the extracellular region but weak staining inside intact cheek cells. Which procedural error most likely explains the result?

45 Why is an unstained cheek-cell preparation important when interpreting Janus green results?

46 A student reports that no mitochondria are present because no blue-green color is visible after staining. Which additional observation would most weaken that conclusion?

47 Which observation provides the strongest evidence that the staining pattern is intracellular rather than deposited on the coverslip?

48 Why should a cheek-cell smear be thin rather than densely layered for Janus green observation?

49 If the same cheek-cell field is examined before and after adding Janus green, which change most strongly supports a specific staining response?

50 A preparation has intense blue-green staining in one cell and almost no staining in neighboring cells. Which explanation is most plausible before concluding that mitochondria are absent from the unstained cells?

51 Which change would most directly test whether the observed color depends on oxidation of Janus green rather than on a permanent pigment in cheek cells?

52 A student uses a very concentrated Janus green solution and observes a uniformly dark cytoplasm. What is the principal interpretive problem?

53 Why should the observer record the time between applying Janus green and examining the cells?

54 A student identifies the dark central region of a cheek cell as a mitochondrion solely because it is prominent. What correction is most appropriate?

55 Which result would most strongly indicate that a negative Janus green result is technically inconclusive rather than biologically meaningful?

56 Why is it inappropriate to infer that cheek cells have no mitochondria merely because they are human epithelial cells rather than muscle cells?

57 A student compares two samples but changes stain concentration, exposure time, and cell density simultaneously. What is the main limitation of the comparison?

58 Which microscopy practice would best distinguish small stained mitochondria from uneven illumination or dust on the optical path?

59 If a mitochondrial inhibitor causes loss of blue-green staining but the cells remain structurally intact, what does this result support most directly?

60 A cheek-cell sample contains many lysed cells and abundant debris. Which conclusion is most defensible if scattered blue-green particles are observed?