BACTERIAL ANATOMY &
PHYSIOLOGY – MCQs (With Answers)
1. Which structure helps bacteria resist phagocytosis?
A. Flagella
B. Capsule
C. Ribosomes
D. Cytoplasmic membrane
Answer: B. Capsule
2. The major component of Gram-positive cell wall is:
A. Lipopolysaccharide
B. Peptidoglycan
C. Mycolic acid
D. Phospholipid
Answer: B. Peptidoglycan
3. Lipopolysaccharide (LPS) is found in:
A. Gram-positive bacteria
B. Gram-negative bacteria
C. Mycoplasma
D. Actinomycetes
Answer: B. Gram-negative bacteria
4. Which part of LPS is responsible for endotoxic activity?
A. O antigen
B. Core polysaccharide
C. Lipid A
D. Periplasm
Answer: C. Lipid A
,5. Bacterial ribosomes are:
A. 40S + 60S
B. 30S + 50S
C. 20S + 40S
D. 50S + 70S
Answer: B. 30S + 50S
6. Which structure is responsible for bacterial motility?
A. Pili
B. Fimbriae
C. Flagella
D. Capsule
Answer: C. Flagella
7. Which bacteria lack a cell wall?
A. Staphylococcus
B. Streptococcus
C. Mycoplasma
D. Pseudomonas
Answer: C. Mycoplasma
8. The site of oxidative phosphorylation in bacteria is:
A. Cytoplasm
B. Ribosome
C. Cell membrane
D. Mitochondria
Answer: C. Cell membrane
9. Endospores are produced by:
A. E. coli
B. Bacillus
C. Vibrio
D. Neisseria
Answer: B. Bacillus
,10. What is the function of Fimbriae?
A. Motility
B. Protein synthesis
C. Attachment to surfaces
D. Sporulation
Answer: C. Attachment to surfaces
11. Peptidoglycan provides:
A. Genetic information
B. Flexibility
C. Shape and rigidity
D. Energy
Answer: C. Shape and rigidity
12. Bacterial DNA is usually:
A. Linear, double-stranded
B. Circular, double-stranded
C. Circular, single-stranded
D. Linear, single-stranded
Answer: B. Circular, double-stranded
13. Plasmids carry genes for:
A. Basic metabolism
B. Antibiotic resistance
C. Cell division
D. Peptidoglycan formation
Answer: B. Antibiotic resistance
14. The space between inner and outer membrane in Gram-negative bacteria
is called:
A. Mesosome
B. Periplasmic space
C. Nucleoid
D. Capsule
Answer: B. Periplasmic space
, 15. The major function of mesosomes is associated with:
A. Protein synthesis
B. Cell wall synthesis and replication
C. Phagocytosis
D. Lipid storage
Answer: B. Cell wall synthesis and replication
16. Which structure helps bacteria transfer genetic material during
conjugation?
A. Fimbriae
B. Pili
C. Flagella
D. Capsule
Answer: B. Pili
17. The rigid layer that maintains bacterial shape is:
A. Cell membrane
B. Capsule
C. Cell wall
D. Ribosome
Answer: C. Cell wall
18. Teichoic acids are present in:
A. Gram-negative bacteria
B. Gram-positive bacteria
C. Mycoplasma
D. Spirochetes
Answer: B. Gram-positive bacteria
19. Which structure prevents desiccation (drying)?
A. Capsule
B. Cell membrane
C. Ribosome
D. Pili
Answer: A. Capsule
PHYSIOLOGY – MCQs (With Answers)
1. Which structure helps bacteria resist phagocytosis?
A. Flagella
B. Capsule
C. Ribosomes
D. Cytoplasmic membrane
Answer: B. Capsule
2. The major component of Gram-positive cell wall is:
A. Lipopolysaccharide
B. Peptidoglycan
C. Mycolic acid
D. Phospholipid
Answer: B. Peptidoglycan
3. Lipopolysaccharide (LPS) is found in:
A. Gram-positive bacteria
B. Gram-negative bacteria
C. Mycoplasma
D. Actinomycetes
Answer: B. Gram-negative bacteria
4. Which part of LPS is responsible for endotoxic activity?
A. O antigen
B. Core polysaccharide
C. Lipid A
D. Periplasm
Answer: C. Lipid A
,5. Bacterial ribosomes are:
A. 40S + 60S
B. 30S + 50S
C. 20S + 40S
D. 50S + 70S
Answer: B. 30S + 50S
6. Which structure is responsible for bacterial motility?
A. Pili
B. Fimbriae
C. Flagella
D. Capsule
Answer: C. Flagella
7. Which bacteria lack a cell wall?
A. Staphylococcus
B. Streptococcus
C. Mycoplasma
D. Pseudomonas
Answer: C. Mycoplasma
8. The site of oxidative phosphorylation in bacteria is:
A. Cytoplasm
B. Ribosome
C. Cell membrane
D. Mitochondria
Answer: C. Cell membrane
9. Endospores are produced by:
A. E. coli
B. Bacillus
C. Vibrio
D. Neisseria
Answer: B. Bacillus
,10. What is the function of Fimbriae?
A. Motility
B. Protein synthesis
C. Attachment to surfaces
D. Sporulation
Answer: C. Attachment to surfaces
11. Peptidoglycan provides:
A. Genetic information
B. Flexibility
C. Shape and rigidity
D. Energy
Answer: C. Shape and rigidity
12. Bacterial DNA is usually:
A. Linear, double-stranded
B. Circular, double-stranded
C. Circular, single-stranded
D. Linear, single-stranded
Answer: B. Circular, double-stranded
13. Plasmids carry genes for:
A. Basic metabolism
B. Antibiotic resistance
C. Cell division
D. Peptidoglycan formation
Answer: B. Antibiotic resistance
14. The space between inner and outer membrane in Gram-negative bacteria
is called:
A. Mesosome
B. Periplasmic space
C. Nucleoid
D. Capsule
Answer: B. Periplasmic space
, 15. The major function of mesosomes is associated with:
A. Protein synthesis
B. Cell wall synthesis and replication
C. Phagocytosis
D. Lipid storage
Answer: B. Cell wall synthesis and replication
16. Which structure helps bacteria transfer genetic material during
conjugation?
A. Fimbriae
B. Pili
C. Flagella
D. Capsule
Answer: B. Pili
17. The rigid layer that maintains bacterial shape is:
A. Cell membrane
B. Capsule
C. Cell wall
D. Ribosome
Answer: C. Cell wall
18. Teichoic acids are present in:
A. Gram-negative bacteria
B. Gram-positive bacteria
C. Mycoplasma
D. Spirochetes
Answer: B. Gram-positive bacteria
19. Which structure prevents desiccation (drying)?
A. Capsule
B. Cell membrane
C. Ribosome
D. Pili
Answer: A. Capsule
