BIOL 271 Microbiology w/ Lab Module 3 Exam Review | LockDown Browser | Portage Learning

BIOL271: Microbiology w/Lab
2026 – 2027 | Portage Learning
Module 3: Microscopy and Microbial Staining Techniques
Exam Review | LockDown Browser
By PortageMaster


Question 1
A micrometer is defined as:
• 10-3
• ✓ 10-6
• 10-9
• 10-12
Correct Answer: 10-6
Feedback: 1 micrometer (µm) = 1 × 10−6 meters = one-millionth of a meter.


Question 2
A micrometer is one-millionth of a meter. True or False?
• ✓ True
• False
Correct Answer: True
Feedback: Correct — 1 µm = 10−6 m. Most bacterial cells are 1–5 µm in size.


Question 3
A nanometer is one-billionth of a meter. True or False?
• ✓ True
• False
Correct Answer: True
Feedback: 1 nm = 1 × 10−9 m. Viruses are typically measured in nanometers (20–300 nm).

, Question 4
A nanometer is defined as:
• 10-3
• 10-6
• ✓ 10-9
• 10-12
Correct Answer: 10-9
Feedback: 1 nanometer (nm) = 1 × 10−9 meters.


Question 5
A nanometer is longer than a micrometer. True or False?
• True
• ✓ False
Correct Answer: False
Feedback: A nanometer (10−9 m) is 1,000 times shorter than a micrometer (10−6 m).


Question 6
A nanometer is 1,000 times smaller than a micrometer. True or False?
• ✓ True
• False
Correct Answer: True
Feedback: 1 µm = 1,000 nm, so a nm is one one-thousandth of a µm.


Question 7
Resolution and contrast are two critical factors that influence your ability to see an object. Explain
each.
✓ Answer: Resolution is the minimum distance between two objects at which they can
still be distinguished as separate — closer objects require higher resolution. Contrast is
the difference in light absorbance between an object and its background — low contrast
makes objects hard to see against their background.
Feedback: Both must be sufficient to image a sample — staining is often used to increase contrast.