Download CSMLS Instrumentation Questions And Answers Grade A+ and more Exams Chemical Instrumentation and Analysis in PDF only on Docsity!
Answers Grade A+
The ability of the microscope to separate small details is defined as: a. magnification b. definition c. resolution d. numerical aperture - correct answer c. resolution is the ability to distinguish between adjacent details or to reveal fine detail. resolving power is measured as the least distance between 2 objectives at which the objects can be discerned as 2 separate structures rather than a single blurred object Sections 90-nm thick are commonly cut with a/an: a. sliding microtome b. ultramicrotome c. rotary microtome d. vibratome - correct answer the ultramicrotome is used to cut 90nm sections for electron microscopy When cutting sections from paraffin blocks, the most common cause of unsatisfactory sections is: a. poor fixation of the tissue b. a flotation bath that is too hot
Answers Grade A+
c. paraffin with a low melting point d. a poor blade edge - correct answer d. poor blade edge is the most common cause (can also be caused by poor fixation) The regular laboratory incubator maintains a temperature of about: a. 4 C b. 28 C c. 37 C d. 60 C - correct answer c. 37 C When the magnification can be changed without the need to refocus, the microscope objectives are said to be: a. parfocal b. binocular c. achromatic d. apochromatic - correct answer a. when objectives are parfocal, all objectives will have the focal point in the same plane and magnification can be changes without the need to refocus
Answers Grade A+
a. 43 C b. 43 F c. 60 C d. 60 F - correct answer c. 60 C, just above the melting point for paraffin Crooked paraffin ribbons may be caused by: a) static electricity b) overchilled blocks c) too much knife tilt d) nonparallel block horizontal edges - correct answer d. the upper and lower edges of the block should be parallel or crooked ribbons may result 10 When using a microscope with a x10 ocular and x objective, the total magnification is approximately: a. 100 b. 400 c. 1, d. 4,000 - correct answer b. 10x 40 = 400 The clearance angle of the microtome blade is routinely:
Answers Grade A+
a. 3- b. 15- c. 30- d. variable - correct answer a. the clearance angle is routinely 3-8 degrees When using paraffin with a melting point fo 55-57 C, the most common temperature for floating sectionsb on a flotation bath is approximately a. 15-20 C b. 35-40 C c. 45-50 C d. 55-60 C - correct answer c. the flotation bath is kept 5-10 C below the melting point of paraffin Compressed or wrinkled sections may be caused by: a. overchilled paraffin blocks b. defects in the blade edge c. the wrong blade tilt d. static electricity - correct answer c. the wrong blade tilt usually too little, is a common cause of compressed, wrinkled or jammed sections.
Answers Grade A+
b. too much blade tilt c. an overheaded flotation bath d. overdehydration of the tissue - correct answer a. A dull blade or too little blade tilt will cause lifting of the section for the blade as the block is raised Microscopic examination of an H&E stained section reveals marked chatter, especially at the edges of the tissue. This was most likely caused by: a. a dull blade b. too little blade tilt c. an overheated flotation bath d. overdehydration - correct answer d. overdehydration of the tissue during processing will cause tissue to harden. During microtomy, this can cause chatter or microscopic vibration especially at the edge of some tissues During cryotomy, sections of varying thickness are obtained. This can most likely be corrected by: a. lowering the cryostat temperature b. warming the blade edge c. increaing the blade tilt
Answers Grade A+
d. decreasing the speed of sectioning - correct answer c. too little blade tilt as well as worn or loose microtome parts When checking the pH of a staining solution, the pH meter should be calibrated using a standard solution with a pH value: a. closest to that of the staining solution b. appoximating that of water c. in any range d. close to 7.0 - correct answer a. for the greatest accuracy, the pH meter should be calibrated with a standard solution having a pH value near that of the staining solution Tissues are subjected to a series of different reagents in a closed processor by: a. tissue transfer b. fluid transfer c. heat transfer d. linear transport - correct answer b. closed processors employ fluid transfer in which the tissue is stationary and the fluids are pumped in and out of the pressurized chamber containing the tissue
