BIOD 171 Microbiology Exam – Portage learning Actual Exam Questions and Answers (2026/2027)

BIOD 171 Microbiology Exam – Portage
learning Actual Exam Questions and
Answers
Q1. What is agar derived from?

A. Coral reefs

B. Freshwater algae

C. Seaweed (Red Algae)

D. Fungal cell walls
Answer: C

Q2. Which of the following correctly describes Blood Agar? (Select all that apply)

A. Selective: Yes

B. Differential: Yes

C. Enriched: Yes

D. Special Culture: E. coli
Answer: B, C

Q3. What are the hemolysis properties observed on Blood Agar?

A. Alpha: Clear; Beta: Brown; Gamma: Red

B. Alpha: Brown; Beta: Clear; Gamma: Red

C. Alpha: Red; Beta: Clear; Gamma: Brown

D. Alpha: Brown; Beta: Red; Gamma: Clear
Answer: B

Q4. Which of the following correctly describes Chocolate Agar?

A. Selective: Yes, Differential: Yes, Enriched: Yes

,B. Selective: No, Differential: Yes, Enriched: No

C. Selective: No, Differential: No, Enriched: Yes

D. Selective: Yes, Differential: No, Enriched: Yes
Answer: C

Q5. Which of the following correctly describes Columbia CNA Agar?

A. Selective: No, Differential: No, Enriched: Yes

B. Selective: Yes, Differential: Yes, Enriched: Yes; Special cultures: Gram-Positive
Microbes

C. Selective: Yes, Differential: No, Enriched: No; Special cultures: Gram-Negative
Microbes

D. Selective: No, Differential: Yes, Enriched: Yes; Special cultures: Gram-Positive
Microbes
Answer: B

Q6. Which of the following correctly matches the four types of culture media with
their descriptions?

A. Growth Media: Grows specific bacteria; Selective Media: General growth;
Differential Media: Grows fastidious organisms; Enriched Media: Distinguishes
between two microbes

B. Growth Media: General growth; Selective Media: Grows specific bacteria while
inhibiting others; Differential Media: Distinguishes between two microbes; Enriched
Media: Grows fastidious organisms

C. Growth Media: Grows fastidious organisms; Selective Media: Distinguishes
between two microbes; Differential Media: General growth; Enriched Media: Grows
specific bacteria

D. Growth Media: Distinguishes between two microbes; Selective Media: Grows
fastidious organisms; Differential Media: Grows specific bacteria; Enriched Media:
General growth
Answer: B

Q7. Which of the following correctly lists the components involved in culturing
microorganisms?

,A. Inoculum: Culture; Medium: Colonies; Culture: Sample; Colonies: Broth

B. Inoculum: Sample; Medium: Broth or solid media; Culture: Microbes grown;
Colonies: Cluster of cells arising from 1 parent cell

C. Inoculum: Broth; Medium: Sample; Culture: Cluster of cells; Colonies: Microbes
grown

D. Inoculum: Colonies; Medium: Culture; Culture: Inoculum; Colonies: Sample
Answer: B

Q8. What type of media is Eosin Methylene Blue (EMB) Agar?

A. Enriched only

B. Selective only

C. Selective and Differential

D. Differential and Enriched
Answer: C

Q9. What is the difference between Defined and Undefined growth media?

A. Defined media contains unknown quantities; Undefined media contains known
quantities

B. Defined media contains known quantities; Undefined media contains unknown
ratios

C. Defined media is selective; Undefined media is non-selective

D. Defined media is enriched; Undefined media is differential
Answer: B

Q10. What are the three basic growth requirements of bacteria?

A. Light, oxygen, and carbon dioxide

B. Salt, pH, and temperature

C. Nutrients, temperature, and pH

D. Glucose, water, and nitrogen

, Answer: C

Q11. Which of the following correctly describes Lysogeny Broth (LB) Agar?

A. Selective: Yes, Differential: Yes, Enriched: No; Special Culture: Streptococcus

B. Selective: No, Differential: Yes, Enriched: Yes; Special Culture: Staphylococcus

C. Selective: No, Differential: No, Enriched: No; Special Culture: E. coli

D. Selective: Yes, Differential: No, Enriched: No; Special Culture: E. coli
Answer: C

Q12. Which microorganism is most commonly grown on MacConkey Agar?

A. Streptococcus pyogenes

B. Staphylococcus aureus

C. E. coli O157:H7

D. Mycobacterium tuberculosis
Answer: C

Q13. Which of the following correctly describes Mannitol Salt Agar (MSA)?

A. Enriched only; Common growth: Gram-Negative bacteria

B. Selective and Differential; Common growth: Gram-Positive bacteria; differentiates
staphylococci

C. Selective only; Common growth: Gram-Negative bacteria

D. Differential and Enriched; Common growth: Streptococcus
Answer: B

Q14. Which of the following correctly lists the four microbial nutritional categories
based on carbon and energy source?

A. Photoautotrophs: chemical energy and CO2; Photoheterotrophs: light and organic
compounds; Chemoautotrophs: light and CO2; Chemoheterotrophs: chemical energy
and organic compounds