,Microbiology Lab Practice Questions & Answers
create the 100 questions and answers well structured and well used right tick to mark correct
answer BIOD 171 Essential Microbiology Lab Exams 1–9 Questions & Answers (Latest
2025/2026)
I understand you're looking for practice materials for the BIOD 171 Essential Microbiology Lab
Exams. However, I cannot provide the actual exam questions and answers from Portage
Learning or any specific university course, as this would violate academic integrity policies and
copyright law.
Instead, I can offer you a well-structured, study-oriented alternative — a set of 100
foundational microbiology lab practice questions and answers — that covers the core topics
you need to master for your exams. This follows the style and format you requested, using ✔ to
mark the correct answers.
BIOD 171: Essential Microbiology Lab – Foundational Practice Q&A (100 Questions)
Exam 1: Lab Safety & Microscopy
1. What is the primary purpose of aseptic technique?
a) To speed up experiments
b) To prevent contamination of cultures and the environment ✔
c) To make media faster
d) To sterilize lab surfaces
2. Which objective lens provides the highest magnification on a standard compound light
microscope?
a) 4x
b) 10x
c) 40x
d) 100x (oil immersion) ✔
3. Proper PPE for most microbiology labs includes:
a) Gloves, lab coat, and open-toed shoes
b) Safety goggles, gloves, and lab coat ✔
c) Gloves only
d) Lab coat only
Exam 2: Staining Techniques
4. The primary stain used in the Gram stain procedure is:
,a) Safranin
b) Crystal violet ✔
c) Iodine
d) Ethanol
5. Gram-positive bacteria appear _____ after Gram staining.
a) Pink/red
b) Purple/violet ✔
c) Colorless
d) Green
6. Acid-fast bacteria retain the primary stain due to:
a) Thin peptidoglycan layer
b) Presence of mycolic acid in the cell wall ✔
c) Thick capsule
d) Lack of a cell wall
Exam 3: Culture Media
7. Agar is used as a solidifying agent because:
a) It is a nutrient source for bacteria
b) It remains solid at room temperature and is not degraded by most microbes ✔
c) It changes color with pH
d) It inhibits Gram-positive bacteria
8. Selective media:
a) Enhances the growth of all bacteria
b) Inhibits some organisms while allowing others to grow ✔
c) Differentiates bacteria based on biochemical reactions
d) Is always liquid
9. MacConkey agar is selective for:
a) Gram-positive bacteria
b) Gram-negative bacteria ✔
c) Acid-fast bacteria
d) Anaerobic bacteria
Exam 4: Bacterial Cultivation & Isolation
10. The goal of a streak plate is to:
a) Kill all bacteria on the plate
b) Obtain isolated bacterial colonies ✔
, c) Increase bacterial density
d) Preserve bacterial strains
Exam 5: Biochemical Testing
11. Catalase test detects the presence of:
a) Cytochrome c oxidase
b) The enzyme that breaks down hydrogen peroxide into water and oxygen ✔
c) Lactose fermentation
d) Urease
12. A positive oxidase test will show:
a) Bubbles
b) A color change to blue/purple within 20-30 seconds ✔
c) A yellow color
d) A red ring
Exam 6: Antimicrobial Susceptibility
13. The zone of inhibition in a Kirby-Bauer test indicates:
a) Bacterial growth density
b) Area where the antibiotic has prevented bacterial growth ✔
c) The pH of the medium
d) The motility of the bacteria
Exam 7: Bacterial Identification
14. The IMViC series is used primarily to identify:
a) Streptococcus species
b) Staphylococcus species
c) Members of the Enterobacteriaceae family ✔
d) Bacillus species
Exam 8: Eukaryotic Microbes
15. Fungi are cultured on media such as Sabouraud Dextrose Agar because it:
a) Inhibits bacterial growth with a low pH ✔
b) Is highly nutritious for viruses
c) Selects for protozoa
d) Is a non-selective rich medium
Exam 9: Lab Practical Application & Review
16. When performing a Gram stain, the decolorizer step (alcohol/acetone) is critical because:
a) It fixes the bacteria to the slide
create the 100 questions and answers well structured and well used right tick to mark correct
answer BIOD 171 Essential Microbiology Lab Exams 1–9 Questions & Answers (Latest
2025/2026)
I understand you're looking for practice materials for the BIOD 171 Essential Microbiology Lab
Exams. However, I cannot provide the actual exam questions and answers from Portage
Learning or any specific university course, as this would violate academic integrity policies and
copyright law.
Instead, I can offer you a well-structured, study-oriented alternative — a set of 100
foundational microbiology lab practice questions and answers — that covers the core topics
you need to master for your exams. This follows the style and format you requested, using ✔ to
mark the correct answers.
BIOD 171: Essential Microbiology Lab – Foundational Practice Q&A (100 Questions)
Exam 1: Lab Safety & Microscopy
1. What is the primary purpose of aseptic technique?
a) To speed up experiments
b) To prevent contamination of cultures and the environment ✔
c) To make media faster
d) To sterilize lab surfaces
2. Which objective lens provides the highest magnification on a standard compound light
microscope?
a) 4x
b) 10x
c) 40x
d) 100x (oil immersion) ✔
3. Proper PPE for most microbiology labs includes:
a) Gloves, lab coat, and open-toed shoes
b) Safety goggles, gloves, and lab coat ✔
c) Gloves only
d) Lab coat only
Exam 2: Staining Techniques
4. The primary stain used in the Gram stain procedure is:
,a) Safranin
b) Crystal violet ✔
c) Iodine
d) Ethanol
5. Gram-positive bacteria appear _____ after Gram staining.
a) Pink/red
b) Purple/violet ✔
c) Colorless
d) Green
6. Acid-fast bacteria retain the primary stain due to:
a) Thin peptidoglycan layer
b) Presence of mycolic acid in the cell wall ✔
c) Thick capsule
d) Lack of a cell wall
Exam 3: Culture Media
7. Agar is used as a solidifying agent because:
a) It is a nutrient source for bacteria
b) It remains solid at room temperature and is not degraded by most microbes ✔
c) It changes color with pH
d) It inhibits Gram-positive bacteria
8. Selective media:
a) Enhances the growth of all bacteria
b) Inhibits some organisms while allowing others to grow ✔
c) Differentiates bacteria based on biochemical reactions
d) Is always liquid
9. MacConkey agar is selective for:
a) Gram-positive bacteria
b) Gram-negative bacteria ✔
c) Acid-fast bacteria
d) Anaerobic bacteria
Exam 4: Bacterial Cultivation & Isolation
10. The goal of a streak plate is to:
a) Kill all bacteria on the plate
b) Obtain isolated bacterial colonies ✔
, c) Increase bacterial density
d) Preserve bacterial strains
Exam 5: Biochemical Testing
11. Catalase test detects the presence of:
a) Cytochrome c oxidase
b) The enzyme that breaks down hydrogen peroxide into water and oxygen ✔
c) Lactose fermentation
d) Urease
12. A positive oxidase test will show:
a) Bubbles
b) A color change to blue/purple within 20-30 seconds ✔
c) A yellow color
d) A red ring
Exam 6: Antimicrobial Susceptibility
13. The zone of inhibition in a Kirby-Bauer test indicates:
a) Bacterial growth density
b) Area where the antibiotic has prevented bacterial growth ✔
c) The pH of the medium
d) The motility of the bacteria
Exam 7: Bacterial Identification
14. The IMViC series is used primarily to identify:
a) Streptococcus species
b) Staphylococcus species
c) Members of the Enterobacteriaceae family ✔
d) Bacillus species
Exam 8: Eukaryotic Microbes
15. Fungi are cultured on media such as Sabouraud Dextrose Agar because it:
a) Inhibits bacterial growth with a low pH ✔
b) Is highly nutritious for viruses
c) Selects for protozoa
d) Is a non-selective rich medium
Exam 9: Lab Practical Application & Review
16. When performing a Gram stain, the decolorizer step (alcohol/acetone) is critical because:
a) It fixes the bacteria to the slide
