BIOD 171 Exam Questions
2024 | (Essential
Microbiology) Complete
200+Questions and Answers
Graded A+
1. What is the primary function of ribosomes in a bacterial cell?
A. DNA replication
B. Protein synthesis
C. Energy production
D. Cell division
Answer: B. Protein synthesis
Explanation: Ribosomes are the sites of protein synthesis in all living cells, including bacteria.
2. Which of the following structures is unique to prokaryotic cells?
A. Nucleus
B. Mitochondria
C. Cell wall
D. Endoplasmic reticulum
Answer: C. Cell wall
Explanation: While many eukaryotic cells also have cell walls (like plants and fungi), the
structure and composition of bacterial cell walls (often made of peptidoglycan) are unique to
prokaryotes.
3. Which of the following is NOT a method of bacterial genetic exchange?
,A. Transformation
B. Conjugation
C. Transduction
D. Transcription
Answer: D. Transcription
Explanation: Transcription is the process of copying DNA into RNA, not a method of genetic
exchange. The other three methods involve the transfer of genetic material between bacteria.
4. What type of stain is used to differentiate between Gram-positive and
Gram-negative bacteria?
A. Simple stain
B. Negative stain
C. Gram stain
D. Acid-fast stain
Answer: C. Gram stain
Explanation: The Gram stain categorizes bacteria into two groups based on the composition of
their cell walls, which helps in identification and treatment options.
5. Which of the following is a characteristic of viruses?
A. They can reproduce independently
B. They are made up of cells
C. They contain DNA or RNA
D. They have ribosomes
Answer: C. They contain DNA or RNA
Explanation: Viruses are acellular and cannot reproduce independently; they rely on host cells
for replication. They also do not contain ribosomes.
6. What is the purpose of using aseptic technique in microbiology?
A. To kill bacteria
B. To prevent contamination
C. To grow bacteria
D. To increase mutation rates
Answer: B. To prevent contamination
Explanation: Aseptic technique is used to minimize contamination of samples and the
environment when handling microorganisms.
, 7. Which of the following bacteria is known for forming endospores?
A. Escherichia coli
B. Staphylococcus aureus
C. Bacillus cereus
D. Neisseria gonorrhoeae
Answer: C. Bacillus cereus
Explanation: Bacillus species, including Bacillus cereus, are known for their ability to form
resilient endospores, allowing them to survive harsh conditions.
8. What type of metabolic process do anaerobic bacteria use to generate
energy?
A. Aerobic respiration
B. Fermentation
C. Photosynthesis
D. Chemiosmosis
Answer: B. Fermentation
Explanation: Anaerobic bacteria generate energy through fermentation processes in the
absence of oxygen.
9. What is the function of the cell membrane in bacteria?
A. Protection against antibiotics
B. Regulation of nutrient transport
C. DNA storage
D. Energy production
Answer: B. Regulation of nutrient transport
Explanation: The cell membrane regulates the passage of substances in and out of the
bacterial cell.
10. What structure is responsible for the motility of bacteria?
A. Capsule
B. Flagella
C. Pili
D. Ribosomes
Answer: B. Flagella
Explanation: Flagella are long, whip-like structures that enable bacterial movement.
2024 | (Essential
Microbiology) Complete
200+Questions and Answers
Graded A+
1. What is the primary function of ribosomes in a bacterial cell?
A. DNA replication
B. Protein synthesis
C. Energy production
D. Cell division
Answer: B. Protein synthesis
Explanation: Ribosomes are the sites of protein synthesis in all living cells, including bacteria.
2. Which of the following structures is unique to prokaryotic cells?
A. Nucleus
B. Mitochondria
C. Cell wall
D. Endoplasmic reticulum
Answer: C. Cell wall
Explanation: While many eukaryotic cells also have cell walls (like plants and fungi), the
structure and composition of bacterial cell walls (often made of peptidoglycan) are unique to
prokaryotes.
3. Which of the following is NOT a method of bacterial genetic exchange?
,A. Transformation
B. Conjugation
C. Transduction
D. Transcription
Answer: D. Transcription
Explanation: Transcription is the process of copying DNA into RNA, not a method of genetic
exchange. The other three methods involve the transfer of genetic material between bacteria.
4. What type of stain is used to differentiate between Gram-positive and
Gram-negative bacteria?
A. Simple stain
B. Negative stain
C. Gram stain
D. Acid-fast stain
Answer: C. Gram stain
Explanation: The Gram stain categorizes bacteria into two groups based on the composition of
their cell walls, which helps in identification and treatment options.
5. Which of the following is a characteristic of viruses?
A. They can reproduce independently
B. They are made up of cells
C. They contain DNA or RNA
D. They have ribosomes
Answer: C. They contain DNA or RNA
Explanation: Viruses are acellular and cannot reproduce independently; they rely on host cells
for replication. They also do not contain ribosomes.
6. What is the purpose of using aseptic technique in microbiology?
A. To kill bacteria
B. To prevent contamination
C. To grow bacteria
D. To increase mutation rates
Answer: B. To prevent contamination
Explanation: Aseptic technique is used to minimize contamination of samples and the
environment when handling microorganisms.
, 7. Which of the following bacteria is known for forming endospores?
A. Escherichia coli
B. Staphylococcus aureus
C. Bacillus cereus
D. Neisseria gonorrhoeae
Answer: C. Bacillus cereus
Explanation: Bacillus species, including Bacillus cereus, are known for their ability to form
resilient endospores, allowing them to survive harsh conditions.
8. What type of metabolic process do anaerobic bacteria use to generate
energy?
A. Aerobic respiration
B. Fermentation
C. Photosynthesis
D. Chemiosmosis
Answer: B. Fermentation
Explanation: Anaerobic bacteria generate energy through fermentation processes in the
absence of oxygen.
9. What is the function of the cell membrane in bacteria?
A. Protection against antibiotics
B. Regulation of nutrient transport
C. DNA storage
D. Energy production
Answer: B. Regulation of nutrient transport
Explanation: The cell membrane regulates the passage of substances in and out of the
bacterial cell.
10. What structure is responsible for the motility of bacteria?
A. Capsule
B. Flagella
C. Pili
D. Ribosomes
Answer: B. Flagella
Explanation: Flagella are long, whip-like structures that enable bacterial movement.
