MCB2010 – How can contrast between a specimen

10 Jun MCB2010 – How can contrast between a specimen

Question
20. How can contrast between a specimen and the background be improved?

A. Heat fixation

B. Staining

C. Steaming the specimen

D. Adjusting the rheostat

E. Adjusting the stage

21. Staining organisms does not kill them.

A. True

B. False

22. The light source in a light microscope can be internal or external.

A. True

B. False

23. The purpose of a condenser is to make illumination more uniform on a specimen.

A. True

B. False

24. Refraction of light occurs as it passes through the condenser.

A. True

B. False

25. A ‘magnified real image’ is produced as light bends through the condenser.

A. True

B. False

26. The ‘magnified real image’ is magnified again as it passes through the ocular lens to produce a virtual image.

A. True

B. False

27. The limit to magnification with a light microscope is what?

A. 1300X

B. 1200X

C. 100X

D. 10X

E. none of the above

28. Image clarity is more easily attained with increasing magnification.

A. True

B. False

29. The term image resolution is synonymous with the term resolving power.

A. True

B. False

30. Resolution improves as the limit of resolution is made larger.

A. True

B. False

31. What is the total magnification of a specimen viewed with a 10x ocular lens and a 45x objective lens?

A. 4.5x

B. 10x

C. 45x

D. 100x

E. 450x

32. What structure does light pass through after leaving the condenser in a compound light microscope?

A. Ocular lens

B. Objective lens

C. Specimen

D. Illuminator

E. All of the above

33. Simple staining is often necessary to improve contrast in which microscope?

A. Compound light microscope

B. Phase-contrast microscope

C. Darkfield microscope

D. Fluorescence microscope

E. Electron microscope

34. Which of the following correctly traces the path of light through the compound microscope?

A. Light source; condenser; specimen; objective lens; ocular lens

B. Condenser; light source; specimen; ocular lens; objective lens

C. Light source; specimen; condenser; objective lens; ocular lens

D. Condenser; light source; specimen; objective lens; ocular lens

E. Light source; condenser; objective lens; specimen; ocular lens

Figure 1

35. In Figure 1, line “C” points to the microscope’s

A. Illuminator

B. Condenser

C. Ocular lens

D. Objective lens

36. In Figure 1, line “A” points to the microscope’s

A. Illuminator

B. Condenser

C. Ocular lens

D. Objective lens

37. In Figure 1, line “B” points to the microscope’s

A. Course/fine adjustment

B. Condenser

C. Specimen

D. Diaphragm

38. In Figure 1, line “D” points to the microscope’s

A. Mechanical stage

B. Condenser

C. Ocular lens

D. Objective lens

39. In Figure 1, line “E” points to the microscope’s

A. Illuminator

B. Rheostat

C. Ocular lens

D. Iris/diaphragm

40. A student is looking at a bacterial specimen using the oil immersion lens, but has forgotten to put immersion oil on the slide. The specimen will appear

A. Smaller than it would if immersion oil was used

B. Larger than it would if immersion oil was used

C. Somewhat fuzzy and have poor resolution

D. The same as it would if the immersion oil was used

E. To have no color

41. The purpose of the ocular lens is to

A. Improve resolution

B. Magnify the image from the objective lens

C. Decrease the refractive index

D. Increase the light

E. Decrease the light

42. In microscopy, the term resolution

A. Refers to the ability to distinguish fine structure and detail in a specimen.

B. Is the same as the total magnification of a specimen.

C. Is improved when longer wavelengths of light are employed.

D. Is only observed in stained specimens.

E. Refers to magnification when using the electron microscope.

43. Most ocular lenses magnify specimens by a factor of

A. 4

B. 10

C. 20

D. 40

E. None of the above

44. A compound light microscope with 2000X total magnification has __X ocular and __X objective lenses

A. 10, 200

B. 200, 10

C. 20, 100

D. 10, 100

E. All of the above

45. Name the three lenses of the compound light microscope

A. Ocular, objective, condenser

B. Projector, condenser, ocular

C. Iris, diaphragm, objective

D. 10,000,000,000

E. None of the above

46. The limit of resolution of the unaided human eye is:

A. 100 microns

B. 0.1 microns

C. 0.1 mm

D. A and C

E. All of these

47. The limit of resolution of a typical light microscope is:

A. 0.2 microns

B. 0.1 microns

C. 0.1 mm

D. None of these

E. All of these

48. Total magnification is

A. Objective lens x ocular lens

B. Objective lens is magnified again by the ocular lens

C. Objective lens x condenser lens

D. A and B

E. None of the above

49. Types of light microscopy include:

A. Bright field

B. Dark field

C. Phase contrast

D. Fluorescent

E. All of the above

50. The measurement of how far apart two points must be for the microscope to view them as being separate is called:

A. Resolution

B. Numerical aperture

C. Limit of resolution

D. Resolving power

E. C and D

51. A measure of a lens’s ability to capture light coming from the specimen and use it to make the image is called:

A. Resolution

B. Numerical aperture

C. Limit of resolution

D. Resolving power

E. C and D

52. This type of microscopy utilizes natural fluorescence of a sample or fluorescent dyes:

A. Dark field

B. Bright field

C. Fluorescent

D. Phase contrast

E. C and D

53. Using this type of microscopy a sample appears dark against a bright background:

A. Dark field

B. Bright field

C. Fluorescent

D. Phase contrast

E. C and D

54. Dark field microscopy is characterized by all EXCEPT:

A. Staining distorts or kills specimen

B. Better resolution than bright field

C. No stain required

D. Light reflected off specimen enters objective

E. Specimen is brightly lit against a dark background

55. When you move the mechanical stage adjustment knob of a light microscope to the left the image moves to the left.

A. True

B. False

56. When you move the mechanical stage adjustment knob of a light microscope to the right the image moves to the left.

A. True

B. False

57. When you move the mechanical stage adjustment knob of a light microscope up the image moves up.

A. True

B. False

58. When you move the mechanical stage adjustment knob of a light microscope down the image moves up.

A. True

B. False

Bacterial Structure (pp.181-184)

59. The most important features of the light microscope include:

A. Magnification

B. Resolution

C. Contrast

D. All of the above

E. None of the above

60. A cellular specimen is made visible by:

A. The cellular cytoplasm

B. Contrast with the foreground of the microscope field

C. Contrast with the background of the microscope field

D. Resolving power

E. C and D

61. What details of cellular structure are more visible after staining provides contrast to a cell with transparent cytoplasm?

A. Morphology

B. Size

C. Arrangement

D. All of the above

E. None of the above

62. Spheres, rods and spirals are all different types of bacterial:

A. Morphologies

B. Arrangements

C. Shapes

D. Species

E. A, C and D

63. Spherical bacterial cells are called:

A. Rods

B. Vibrios

C. Cocci

D. Spirochetes

E. B and D

64. Curved bacterial cells are called:

A. Rods

B. Vibrios

C. Cocci

D. Spirochetes

E. B and D

65. Pleomorphism indicates that an organism:

A. Has one shape

B. Is vibrio

C. Is coccobaccili

D. Has many shapes

E. Is Corynebacterium xerosis

66. A species of bacterial organism has spiral shaped members, ovoid members and coccobacilli members, this organism is:

A. Crazy

B. Pleomorphic

C. Monomorphic

D. Archaea

E. Eukaryotic

Ubiquity of Microorganisms (2.1)

67. Environmental factors affecting microbial growth include:

A. pH

B. Oxygen

C. Temperature

D. Osmotic pressure

E. All of the above

68. Characteristics of saprophytes include

A. Nutrient recyclers

B. Decomposers of dead organic matter

C. Organisms that live in or on animals

D. Organisms that live in or on plants

E. All of the above

69. Microorganisms are not free-living

A. True

B. False

70. All microorganisms are pathogenic

A. True

B. False

71. Define ubiquitous

A. Found in animals

B. Found in plants

C. Found everywhere

D. Found nowhere

E. Rarely found

72. ‘Capable of producing a disease state if introduced into a specific part of the body’ is the definition of what?

A. Mutualistic

B. Commensal

C. Reservoir

D. Opportunistic

E. None of the above

Microscopic Examination of Eukaryotic Microbes (3.3)

73. Which of the following organisms are prokaryotes?

A. Fungi

B. Plants

C. Archaea

D. Bacteria

E. C and D

74. Which of the following does not characterize Eukaryotes?

A. Membrane bound organelles

B. Whip like flagellar movement

C. Mitotic division

D. Single circular molecule of DNA called chromosome

E. Can be 10-100 microns in size

75. The four kingdoms of Eukaryotes are:

A. Plantae, Fungi, Animalia, Protista

B. Protista, Archaea, Animalia, Bacteria

C. Algae, Protozoan, Helminths, Animalia

D. Yeasts, Algae, Protozoans, Animalia

76. What is the main feature that distinguishes prokaryotes from eukaryotes?

A. Ribosome

B. Cell wall

C. Flagella

D. Nucleus

E. None of the above

77. How can you identify streptococci with a microscope?

A. Shape of cells

B. Size of cells

C. Arrangement of cells

D. All of the above

E. None of the above

78. How do bacteria move?

A. Pili

B. Axial filament

C. Flagella

D. All of the above

E. B and C

79. The following are prokaryotes:

A. Fungi

B. Plants

C. Algae

D. All of the above

E. None of the above

80. Which of the organisms below have organelles?

A. Eukaryotes

B. Prokaryotes

C. plants

D. A and C

E. none of the above

81. DNA is stored in what structure in prokaryotes?

A. Nucleoid

B. Plasmid

C. Chromosome

D. All of the above

E. Nucleus