Portage Learning / Geneva
3 MAXE · 171 DOIB
GENEVA
College
COLLEGE
G
Department of Natural Sciences
EST. 1848
P R O C H R I S T O E T P AT R I A
BIOD 171 Exam 3 Study
E SS E N T I A L L A B M I C R O B I O LO G Y — M I C R O S CO PY A N D STA I N I N G
INSTITUTION Portage Learning / Geneva College COURSE CODE BIOD 171
PROGRAM Pre-Nursing / Health Sciences ACADEMIC YEAR
EXAM TITLE BIOD 171 Exam 3 Study TOTAL QUESTIONS 22 Questions
COURSE TITLE Essential Lab Microbiology FORMAT Multiple Choice — Select the
Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless "Select all that apply" is indicated.
▸ Content covers microscopy principles, staining techniques, Gram classification, and clinical diagnostic
staining.
▸ Correct answers and detailed rationales appear below each question.
, SECTION I — BIOD 171: MICROSCOPY AND STAINING —
Questions 1 – 22
EXAM 3 STUDY
1. True or False: A nanometer (10⁻⁹ m) is longer than a micrometer (10⁻⁶ m).
A. True
B. False; a nanometer is 1,000 times smaller than a micrometer
CORRECT ANSWER B — False; a nanometer is 1,000 times smaller
RATIONALE A micrometer (µm) = 10⁻⁶ m (one-millionth of a meter). A nanometer (nm) = 10⁻⁹ m
(one-billionth of a meter). Since 10⁻⁹ is 1,000 times smaller than 10⁻⁶, a nanometer
is much shorter than a micrometer. Most bacteria are 1–10 µm; viruses are
typically 30–150 nm. Understanding these scale differences is essential for
microscopy and microbiology.
2. Resolution and contrast are two critical factors influencing your ability to see an object.
Which of the following correctly defines each?
A. Resolution = light absorption difference; Contrast = distance between two visible objects
B. Resolution = distance between two objects that appear separate; Contrast = difference in
light absorption by objects
C. Resolution = magnification power; Contrast = color of the specimen
D. Resolution = specimen thickness; Contrast = specimen temperature
CORRECT ANSWER B — Resolution: distance between two distinguishable objects; Contrast:
difference in light absorption
RATIONALE Resolution (resolving power) is the minimum distance at which two adjacent
objects can be distinguished as separate — poor resolution causes objects to blur
together. Contrast is the difference in light absorbance between an object and its
background — poor contrast (e.g., unstained transparent cells) makes
visualization difficult. Both are critical for effective microscopy. Option A reverses
the definitions.
3 MAXE · 171 DOIB
GENEVA
College
COLLEGE
G
Department of Natural Sciences
EST. 1848
P R O C H R I S T O E T P AT R I A
BIOD 171 Exam 3 Study
E SS E N T I A L L A B M I C R O B I O LO G Y — M I C R O S CO PY A N D STA I N I N G
INSTITUTION Portage Learning / Geneva College COURSE CODE BIOD 171
PROGRAM Pre-Nursing / Health Sciences ACADEMIC YEAR
EXAM TITLE BIOD 171 Exam 3 Study TOTAL QUESTIONS 22 Questions
COURSE TITLE Essential Lab Microbiology FORMAT Multiple Choice — Select the
Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless "Select all that apply" is indicated.
▸ Content covers microscopy principles, staining techniques, Gram classification, and clinical diagnostic
staining.
▸ Correct answers and detailed rationales appear below each question.
, SECTION I — BIOD 171: MICROSCOPY AND STAINING —
Questions 1 – 22
EXAM 3 STUDY
1. True or False: A nanometer (10⁻⁹ m) is longer than a micrometer (10⁻⁶ m).
A. True
B. False; a nanometer is 1,000 times smaller than a micrometer
CORRECT ANSWER B — False; a nanometer is 1,000 times smaller
RATIONALE A micrometer (µm) = 10⁻⁶ m (one-millionth of a meter). A nanometer (nm) = 10⁻⁹ m
(one-billionth of a meter). Since 10⁻⁹ is 1,000 times smaller than 10⁻⁶, a nanometer
is much shorter than a micrometer. Most bacteria are 1–10 µm; viruses are
typically 30–150 nm. Understanding these scale differences is essential for
microscopy and microbiology.
2. Resolution and contrast are two critical factors influencing your ability to see an object.
Which of the following correctly defines each?
A. Resolution = light absorption difference; Contrast = distance between two visible objects
B. Resolution = distance between two objects that appear separate; Contrast = difference in
light absorption by objects
C. Resolution = magnification power; Contrast = color of the specimen
D. Resolution = specimen thickness; Contrast = specimen temperature
CORRECT ANSWER B — Resolution: distance between two distinguishable objects; Contrast:
difference in light absorption
RATIONALE Resolution (resolving power) is the minimum distance at which two adjacent
objects can be distinguished as separate — poor resolution causes objects to blur
together. Contrast is the difference in light absorbance between an object and its
background — poor contrast (e.g., unstained transparent cells) makes
visualization difficult. Both are critical for effective microscopy. Option A reverses
the definitions.
