Portage Learning Microbiology
BIOD 171 | Module 3 Exam |
Questions & Verified Answers | A+
Graded | 2025/2026 Edition
Section 1: Introduction
This document provides the verified Module 3 Exam for BIOD 171 – Microbiology from
Portage Learning, updated for the 2025/2026 academic cycle. It focuses on microbial growth,
including environmental factors, culture techniques, and growth phases. All questions include
100% accurate answers, A+ graded, to enhance understanding of microbial proliferation.
Section 2: Exam Questions and Answers
Format: Multiple-choice questions
• Four answer choices per question (A–D)
• Correct answer highlighted
• Includes clarifying notes where applicable
1. What is the optimal pH for most bacterial growth?
(a) 2-4
(b) 6-7
(c) 8-10
(d) 11-13
6-7
Note: Neutral pH supports the activity of most bacterial enzymes.
2. Which factor is most critical for microbial growth?
(a) Light
(b) Temperature
(c) Color
(d) Sound
Temperature
Note: Temperature affects enzyme function and metabolic rates.
3. What is the lag phase in bacterial growth?
(a) Rapid division
(b) Preparation for growth
(c) Death phase
, (d) Stationary phase
Preparation for growth
Note: Bacteria adapt to the environment during this phase.
4. Which medium is used to grow fastidious bacteria?
(a) Nutrient agar
(b) Blood agar
(c) MacConkey agar
(d) EMB agar
Blood agar
Note: Blood agar provides nutrients for demanding species.
5. What is the purpose of a pure culture?
(a) Mixed microbial growth
(b) Single species isolation
(c) Nutrient enrichment
(d) pH adjustment
Single species isolation
Note: Ensures study of one bacterial type.
6. Which temperature range is ideal for psychrophiles?
(a) 0-20°C
(b) 20-40°C
(c) 40-60°C
(d) 60-80°C
0-20°C
Note: Psychrophiles thrive in cold environments.
7. What is the log phase of bacterial growth?
(a) Slow growth
(b) Exponential growth
(c) Death phase
(d) Stationary phase
Exponential growth
Note: Rapid cell division occurs here.
8. Which method is used to count viable bacteria?
(a) Spectrophotometry
(b) Plate count
BIOD 171 | Module 3 Exam |
Questions & Verified Answers | A+
Graded | 2025/2026 Edition
Section 1: Introduction
This document provides the verified Module 3 Exam for BIOD 171 – Microbiology from
Portage Learning, updated for the 2025/2026 academic cycle. It focuses on microbial growth,
including environmental factors, culture techniques, and growth phases. All questions include
100% accurate answers, A+ graded, to enhance understanding of microbial proliferation.
Section 2: Exam Questions and Answers
Format: Multiple-choice questions
• Four answer choices per question (A–D)
• Correct answer highlighted
• Includes clarifying notes where applicable
1. What is the optimal pH for most bacterial growth?
(a) 2-4
(b) 6-7
(c) 8-10
(d) 11-13
6-7
Note: Neutral pH supports the activity of most bacterial enzymes.
2. Which factor is most critical for microbial growth?
(a) Light
(b) Temperature
(c) Color
(d) Sound
Temperature
Note: Temperature affects enzyme function and metabolic rates.
3. What is the lag phase in bacterial growth?
(a) Rapid division
(b) Preparation for growth
(c) Death phase
, (d) Stationary phase
Preparation for growth
Note: Bacteria adapt to the environment during this phase.
4. Which medium is used to grow fastidious bacteria?
(a) Nutrient agar
(b) Blood agar
(c) MacConkey agar
(d) EMB agar
Blood agar
Note: Blood agar provides nutrients for demanding species.
5. What is the purpose of a pure culture?
(a) Mixed microbial growth
(b) Single species isolation
(c) Nutrient enrichment
(d) pH adjustment
Single species isolation
Note: Ensures study of one bacterial type.
6. Which temperature range is ideal for psychrophiles?
(a) 0-20°C
(b) 20-40°C
(c) 40-60°C
(d) 60-80°C
0-20°C
Note: Psychrophiles thrive in cold environments.
7. What is the log phase of bacterial growth?
(a) Slow growth
(b) Exponential growth
(c) Death phase
(d) Stationary phase
Exponential growth
Note: Rapid cell division occurs here.
8. Which method is used to count viable bacteria?
(a) Spectrophotometry
(b) Plate count
