PORTAGE LEARNING
14/May/2026 — 9:32 AM
Module 3 Exam - Requires Respondus LockDown Browser + Webcam
Due No due date Points 100 Questions 35 Time Limit 120 Minutes Requires Respondus LockDown Browser
Instructions
Please read the following before beginning the exam:
You must TYPE your work for calculations or give an explanation for short answer questions in order to receive credit.
You may only use the methods and explanations provided by this course for your answers. The use of a method or
explanation that was not taught in this course is a violation of the Academic Integrity Policy.
You MUST only use the exam resource bank that is provided within the exam.
Any equation or constant used on an exam that is not from the exam resource bank and is different from the method
taught in this course will be considered an outside source and a violation of the Academic Integrity Policy.
During module exams you may not use any outside source of information such as the module, problem sets, notes,
Internet, tutor, etc.
The only items you are allowed to have in front of you are your computer, 1-2 pieces of blank scratch paper, a
calculator (non-cell phone), and a pen/pencil.
Your desk should be free of all other items and clutter.
Attempt History
Attempt Time Score
LATEST
Question 1 pts
Resource Bank
Scientific Calculator
A clinical microbiologist receives a sputum sample from a patient with suspected tuberculosis. The sample appears as a
clear, thin fluid with no visible particles. In your own words, explain why staining is essential for visualizing most bacterial
cells under a light microscope, including two specific physical properties of bacteria that make them difficult to see.
Answer: Bacterial cells are typically 1-10 micrometers in size, near the resolution limit of light microscopy. They are also
transparent and colorless, with refractive indices very close to water, making them nearly invisible against a bright
background. Staining increases contrast by adding color and highlights specific cellular structures, allowing
differentiation of morphology, arrangement, and Gram reaction.
Correct!
Question 2 pts
, Resource Bank
Scientific Calculator
The total magnification of a compound light microscope is calculated by __________ the power of the objective lens and the
power of the __________.
Answer: multiplying, eyepiece (or ocular)
Correct!
Question 3 pts
Resource Bank
Scientific Calculator
Match the microscope type to its distinguishing feature or application:
Microscope Type Feature/Application
1. Brightfield a) Uses UV light to excite fluorescent dyes; identifies specific molecules
2. Phase-contrast b) Illuminates sample from below; dark specimen on bright background
3. Dark field c) Converts phase shifts in light passing through specimen to brightness changes
4. Fluorescence d) Standard microscope; requires staining for most specimens
Answer: 1-d, 2-c, 3-b, 4-a
Correct!
Question 4 pts
Resource Bank
Scientific Calculator
A microbiologist uses a 100x oil immersion objective with a 10x eyepiece to examine a blood smear. What is the total
magnification?
a) 100x
b) 500x
c) 1000x
d) 2000x
Correct!
Question 5 pts
14/May/2026 — 9:32 AM
Module 3 Exam - Requires Respondus LockDown Browser + Webcam
Due No due date Points 100 Questions 35 Time Limit 120 Minutes Requires Respondus LockDown Browser
Instructions
Please read the following before beginning the exam:
You must TYPE your work for calculations or give an explanation for short answer questions in order to receive credit.
You may only use the methods and explanations provided by this course for your answers. The use of a method or
explanation that was not taught in this course is a violation of the Academic Integrity Policy.
You MUST only use the exam resource bank that is provided within the exam.
Any equation or constant used on an exam that is not from the exam resource bank and is different from the method
taught in this course will be considered an outside source and a violation of the Academic Integrity Policy.
During module exams you may not use any outside source of information such as the module, problem sets, notes,
Internet, tutor, etc.
The only items you are allowed to have in front of you are your computer, 1-2 pieces of blank scratch paper, a
calculator (non-cell phone), and a pen/pencil.
Your desk should be free of all other items and clutter.
Attempt History
Attempt Time Score
LATEST
Question 1 pts
Resource Bank
Scientific Calculator
A clinical microbiologist receives a sputum sample from a patient with suspected tuberculosis. The sample appears as a
clear, thin fluid with no visible particles. In your own words, explain why staining is essential for visualizing most bacterial
cells under a light microscope, including two specific physical properties of bacteria that make them difficult to see.
Answer: Bacterial cells are typically 1-10 micrometers in size, near the resolution limit of light microscopy. They are also
transparent and colorless, with refractive indices very close to water, making them nearly invisible against a bright
background. Staining increases contrast by adding color and highlights specific cellular structures, allowing
differentiation of morphology, arrangement, and Gram reaction.
Correct!
Question 2 pts
, Resource Bank
Scientific Calculator
The total magnification of a compound light microscope is calculated by __________ the power of the objective lens and the
power of the __________.
Answer: multiplying, eyepiece (or ocular)
Correct!
Question 3 pts
Resource Bank
Scientific Calculator
Match the microscope type to its distinguishing feature or application:
Microscope Type Feature/Application
1. Brightfield a) Uses UV light to excite fluorescent dyes; identifies specific molecules
2. Phase-contrast b) Illuminates sample from below; dark specimen on bright background
3. Dark field c) Converts phase shifts in light passing through specimen to brightness changes
4. Fluorescence d) Standard microscope; requires staining for most specimens
Answer: 1-d, 2-c, 3-b, 4-a
Correct!
Question 4 pts
Resource Bank
Scientific Calculator
A microbiologist uses a 100x oil immersion objective with a 10x eyepiece to examine a blood smear. What is the total
magnification?
a) 100x
b) 500x
c) 1000x
d) 2000x
Correct!
Question 5 pts
