Module 3 BIOD 171
True or False: A nanometeris longer than a micrometer.
Correct answer- False. A nanometer is 1,000 times smaller than a
... [Show More] micrometer.
What is the total magnification (relative to your eye) of a sample imaged with a 60x objective and a 10x eyepiece? Show your math.
Correct answer- 60 x 10 = 600x magnification
Assuming a fixed ocular, identify the part of the microscope you would adjust to enhance the magnification of a sample.
A. Objective
B. Condenser
C. Iris diaphragm
D. Eye piece
Correct answer- A. Only the oculars (eyepiece) and the objectives contribute to the magnification of the sample. Since the eyepiece is fixed, only the objectives could be altered.
What is the total magnification (relative to your eye) of a sample imaged with a 20x objective and a 15x eyepiece? Show your math.
Correct answer- 20 x 15 = 300x magnification
True or False: Staining is often required to image a cell that is adherent and flat (thin). Correct answer- True. Adherent, flat and unstained cells are almost invisible due to the limits on both resolution and contrast. Therefore, cell staining is often required to adequately image the sample.
Assuming a constant (non-adjustable) light source power, identify the part of the microscope you would adjust to limit the amount of light entering the microscope.Select all that apply.
A. Objective
B. Condenser
C. Iris diaphragm
D. Eye piece
Correct answer- C. The iris controls the amount of light that passes through the sample and into the objective lens. Thus, it can be adjusted (opened or closed) to alter the amount of light.
This type of microscope is best suited for visualizing GFP, RFP and YFP proteins. Correct answer- Fluorescence
True or False: A cell that is adherent, flat (thin) and unstained is easily identified using bright field microscopy.
Correct answer- False.
Adherent, flat cells are almost invisible due to the limits on both resolution and contrast.
True or False: The distinguishing characteristic of Gram-Negative bacteria is the presence of LPS in the outer membrane.
Correct answer- True
True or False: If you wish to study the motility of an organism you cannot heat fix, but you can chemically fix the specimen.
Correct answer- False.
Both heat and chemical fixation strategies will kill the cell, making motility observations impossible. [Show Less]