ENVS 2126 Exam 1 Practice Questions & Answers
(Verified Update)
This comprehensive study guide covers the core domains tested
on ENVS 2126 Exam 1: Environmental and Anthropogenic
Impacts of Microbes at Louisiana State University. It includes
original practice questions with detailed rationales, organized
by the core exam domains: Microbial Structure & Function,
Microbial Genetics & Molecular Biology, Microbial Ecology &
Environmental Microbiology, Pathogens & Immunology, and
Applied Microbiology & Biotechnology.
Exam Overview & Blueprint:
Parameter Details
Course Environmental and Anthropogenic Impacts of Microbes (ENVS 2126)
Exam
Multiple-choice, true/false, and short-answer questions
Format
Prokaryotic vs. eukaryotic cells, cell structure, macromolecules, microbial genetics, PCR,
Core Topics
microbial ecology, eutrophication, pathogens, bioremediation
,Parameter Details
Key
Environmental Microbiology, 3rd Edition (Pepper, Gerba, Gentry)
Textbook
2026 Focus Application-based questions, microbial identification scenarios, molecular biology calculations
Section 1: Microbial Structure & Function
Q1. What is the main difference between a prokaryote and a
eukaryote?
A) Prokaryotes have a nucleus; eukaryotes do not
B) Eukaryotes have membrane-bound organelles; prokaryotes
do not
C) Prokaryotes are larger than eukaryotes
D) Eukaryotes lack ribosomes
Answer: B
Rationale: The main difference is that eukaryotes have
membrane-bound organelles (including a true nucleus), while
prokaryotes do not. This fundamental distinction affects cellular
organization and function.
Q2. Which of the following represents the correct size order
from largest to smallest?
,A) Tree, animal cell, bacterial cell, virus, water molecule
B) Animal cell, tree, bacterial cell, water molecule, virus
C) Bacterial cell, virus, animal cell, tree, water molecule
D) Virus, bacterial cell, animal cell, tree, water molecule
Answer: A
Rationale: The correct size order from largest to smallest is:
tree (multicellular organism), animal cell (eukaryotic), bacterial
cell (prokaryotic), virus (acellular), water molecule (molecular).
Q3. What is the difference between bacteria and viruses?
A) Bacteria have a nucleus; viruses do not
B) Bacteria can grow independently of a host; viruses cannot
C) Viruses are larger than bacteria
D) Bacteria are acellular; viruses are cellular
Answer: B
Rationale: Bacteria can grow independently of a host (they are
living cells), while viruses cannot replicate without a host cell
(they are obligate intracellular parasites).
Q4. Which of the following is NOT a major class of
proteobacteria?
A) Alpha Proteobacteria
B) Beta Proteobacteria
C) Gamma Proteobacteria
D) Omega Proteobacteria
, Answer: D
Rationale: The major classes of proteobacteria are Alpha, Beta,
Gamma, Delta, and Epsilon. Omega Proteobacteria is not a
recognized class.
Q5. Which organism is most likely to form a biofilm such as the
type that causes respiratory problems in intubated cystic
fibrosis patients?
A) Escherichia coli
B) Pseudomonas aeruginosa
C) Staphylococcus aureus
D) Bacillus subtilis
Answer: B
Rationale: Pseudomonas aeruginosa is known for forming
biofilms in the lungs of cystic fibrosis patients and on medical
devices such as intubation tubes.
Q6. What is the function of prokaryotic gas vesicles?
A) To confer buoyancy on cells by decreasing their density
B) To provide structural support
C) To store nutrients
D) To facilitate movement
Answer: A
Rationale: Gas vesicles confer buoyancy on cells by decreasing
(Verified Update)
This comprehensive study guide covers the core domains tested
on ENVS 2126 Exam 1: Environmental and Anthropogenic
Impacts of Microbes at Louisiana State University. It includes
original practice questions with detailed rationales, organized
by the core exam domains: Microbial Structure & Function,
Microbial Genetics & Molecular Biology, Microbial Ecology &
Environmental Microbiology, Pathogens & Immunology, and
Applied Microbiology & Biotechnology.
Exam Overview & Blueprint:
Parameter Details
Course Environmental and Anthropogenic Impacts of Microbes (ENVS 2126)
Exam
Multiple-choice, true/false, and short-answer questions
Format
Prokaryotic vs. eukaryotic cells, cell structure, macromolecules, microbial genetics, PCR,
Core Topics
microbial ecology, eutrophication, pathogens, bioremediation
,Parameter Details
Key
Environmental Microbiology, 3rd Edition (Pepper, Gerba, Gentry)
Textbook
2026 Focus Application-based questions, microbial identification scenarios, molecular biology calculations
Section 1: Microbial Structure & Function
Q1. What is the main difference between a prokaryote and a
eukaryote?
A) Prokaryotes have a nucleus; eukaryotes do not
B) Eukaryotes have membrane-bound organelles; prokaryotes
do not
C) Prokaryotes are larger than eukaryotes
D) Eukaryotes lack ribosomes
Answer: B
Rationale: The main difference is that eukaryotes have
membrane-bound organelles (including a true nucleus), while
prokaryotes do not. This fundamental distinction affects cellular
organization and function.
Q2. Which of the following represents the correct size order
from largest to smallest?
,A) Tree, animal cell, bacterial cell, virus, water molecule
B) Animal cell, tree, bacterial cell, water molecule, virus
C) Bacterial cell, virus, animal cell, tree, water molecule
D) Virus, bacterial cell, animal cell, tree, water molecule
Answer: A
Rationale: The correct size order from largest to smallest is:
tree (multicellular organism), animal cell (eukaryotic), bacterial
cell (prokaryotic), virus (acellular), water molecule (molecular).
Q3. What is the difference between bacteria and viruses?
A) Bacteria have a nucleus; viruses do not
B) Bacteria can grow independently of a host; viruses cannot
C) Viruses are larger than bacteria
D) Bacteria are acellular; viruses are cellular
Answer: B
Rationale: Bacteria can grow independently of a host (they are
living cells), while viruses cannot replicate without a host cell
(they are obligate intracellular parasites).
Q4. Which of the following is NOT a major class of
proteobacteria?
A) Alpha Proteobacteria
B) Beta Proteobacteria
C) Gamma Proteobacteria
D) Omega Proteobacteria
, Answer: D
Rationale: The major classes of proteobacteria are Alpha, Beta,
Gamma, Delta, and Epsilon. Omega Proteobacteria is not a
recognized class.
Q5. Which organism is most likely to form a biofilm such as the
type that causes respiratory problems in intubated cystic
fibrosis patients?
A) Escherichia coli
B) Pseudomonas aeruginosa
C) Staphylococcus aureus
D) Bacillus subtilis
Answer: B
Rationale: Pseudomonas aeruginosa is known for forming
biofilms in the lungs of cystic fibrosis patients and on medical
devices such as intubation tubes.
Q6. What is the function of prokaryotic gas vesicles?
A) To confer buoyancy on cells by decreasing their density
B) To provide structural support
C) To store nutrients
D) To facilitate movement
Answer: A
Rationale: Gas vesicles confer buoyancy on cells by decreasing
