BMS 127 | COMPLETE EXAM 2026/2027 | QUESTIONS AND
100% VERIFIED ANSWERS | PASS GUARANTEE
1. Which structural component is responsible for the Gram-positive cell wall
retaining crystal violet stain?
A. Outer membrane
B. Lipopolysaccharide (LPS)
C. Thick peptidoglycan layer
D. Flagella
2. What is the primary chemical component of bacterial peptidoglycan?
A. Phospholipids
B. Chitin
C. N-acetylglucosamine and N-acetylmuramic acid
D. Cellulose
3. Endotoxin is chemically composed of which molecule found in Gram-
negative bacteria?
A. Mycolic acid
B. Teichoic acid
C. Peptidoglycan
D. Lipopolysaccharide (LPS)
4. Which structure allows bacteria to adhere to host tissues and mediates
conjugation in some species?
A. Endospore
B. Flagella
C. Capsule
D. Pili (fimbriae)
5. Bacterial endospores are most notably resistant to which of the following?
A. Antibiotic beta-lactams
B. Bacteriophage infection
Page 1 of 36
, C. Osmotic lysis only
D. Heat and desiccation
6. Which genus is best known for producing endospores that survive
autoclaving failures?
A. Treponema
B. Bacillus
C. Mycoplasma
D. Neisseria
7. The bacterial capsule primarily contributes to virulence by:
A. Producing exotoxins
B. Inhibiting phagocytosis
C. Forming pili
D. Enabling motility
8. Which of the following bacteria lacks a cell wall entirely?
A. Staphylococcus aureus
B. Mycoplasma pneumoniae
C. Escherichia coli
D. Bacillus anthracis
9. Peritrichous flagellar arrangement refers to flagella that are:
A. Absent from the cell
B. Distributed over the entire cell surface
C. Located at a single pole
D. Located at both poles
10. Which staining technique differentiates bacteria based on cell wall
composition using crystal violet and safranin?
A. Gram stain
B. Acid-fast stain
C. Endospore stain
D. Capsule stain
11. Mycobacterium species are best visualized using which stain due to their
waxy mycolic acid cell wall?
A. Gram stain
Page 2 of 36
, B. Giemsa stain
C. Negative stain
D. Acid-fast (Ziehl-Neelsen) stain
12. Binary fission in bacteria results in which type of reproduction?
A. Meiotic division
B. Sexual reproduction
C. Asexual, producing genetically identical daughter cells
D. Budding with genetic recombination
13. What is the primary function of bacterial ribosomes in the 70S
configuration?
A. Protein synthesis
B. DNA replication
C. ATP synthesis
D. Lipid metabolism
14. Which environmental condition defines an obligate anaerobe?
A. Cannot survive in the presence of oxygen
B. Requires only trace oxygen
C. Requires oxygen to survive
D. Grows equally well with or without oxygen
15. Facultative anaerobes are best described as organisms that:
A. Only grow at high CO2 concentrations
B. Die immediately when exposed to oxygen
C. Can grow with or without oxygen, preferring oxygen when available
D. Require strict anaerobic conditions
16. The lag phase of a bacterial growth curve is characterized by:
A. Death exceeding new cell formation
B. Metabolic adaptation with minimal cell division
C. Depletion of nutrients causing rapid death
D. Exponential increase in cell number
17. During which phase of bacterial growth does cell division occur at a
constant, maximal rate?
A. Death phase
Page 3 of 36
, B. Log (exponential) phase
C. Stationary phase
D. Lag phase
18. The stationary phase of bacterial growth occurs primarily because of:
A. Endospore germination
B. Optimal nutrient availability
C. Nutrient depletion and waste accumulation
D. Genetic mutation rates increasing
19. Which term describes bacteria that require an external source of organic
carbon for energy?
A. Chemolithotrophs
B. Autotrophs
C. Photoautotrophs
D. Heterotrophs
20. Obligate intracellular bacteria such as Rickettsia and Chlamydia are
unable to survive outside host cells because they:
A. Cannot undergo binary fission
B. Lack a cell wall
C. Lack the ability to produce their own ATP
D. Lack ribosomes
21. Which of the following best describes bacterial plasmids?
A. Structural cell wall proteins
B. RNA molecules used for translation
C. Linear chromosomal DNA
D. Small, circular, extrachromosomal DNA that often carries antibiotic
resistance genes
22. Transformation in bacterial genetics refers to:
A. Spontaneous mutation of existing DNA
B. Uptake of naked DNA from the environment
C. Transfer of DNA via a bacteriophage
D. Direct cell-to-cell contact via a pilus
23. Bacterial conjugation requires which structure to transfer genetic material
between cells?
Page 4 of 36
100% VERIFIED ANSWERS | PASS GUARANTEE
1. Which structural component is responsible for the Gram-positive cell wall
retaining crystal violet stain?
A. Outer membrane
B. Lipopolysaccharide (LPS)
C. Thick peptidoglycan layer
D. Flagella
2. What is the primary chemical component of bacterial peptidoglycan?
A. Phospholipids
B. Chitin
C. N-acetylglucosamine and N-acetylmuramic acid
D. Cellulose
3. Endotoxin is chemically composed of which molecule found in Gram-
negative bacteria?
A. Mycolic acid
B. Teichoic acid
C. Peptidoglycan
D. Lipopolysaccharide (LPS)
4. Which structure allows bacteria to adhere to host tissues and mediates
conjugation in some species?
A. Endospore
B. Flagella
C. Capsule
D. Pili (fimbriae)
5. Bacterial endospores are most notably resistant to which of the following?
A. Antibiotic beta-lactams
B. Bacteriophage infection
Page 1 of 36
, C. Osmotic lysis only
D. Heat and desiccation
6. Which genus is best known for producing endospores that survive
autoclaving failures?
A. Treponema
B. Bacillus
C. Mycoplasma
D. Neisseria
7. The bacterial capsule primarily contributes to virulence by:
A. Producing exotoxins
B. Inhibiting phagocytosis
C. Forming pili
D. Enabling motility
8. Which of the following bacteria lacks a cell wall entirely?
A. Staphylococcus aureus
B. Mycoplasma pneumoniae
C. Escherichia coli
D. Bacillus anthracis
9. Peritrichous flagellar arrangement refers to flagella that are:
A. Absent from the cell
B. Distributed over the entire cell surface
C. Located at a single pole
D. Located at both poles
10. Which staining technique differentiates bacteria based on cell wall
composition using crystal violet and safranin?
A. Gram stain
B. Acid-fast stain
C. Endospore stain
D. Capsule stain
11. Mycobacterium species are best visualized using which stain due to their
waxy mycolic acid cell wall?
A. Gram stain
Page 2 of 36
, B. Giemsa stain
C. Negative stain
D. Acid-fast (Ziehl-Neelsen) stain
12. Binary fission in bacteria results in which type of reproduction?
A. Meiotic division
B. Sexual reproduction
C. Asexual, producing genetically identical daughter cells
D. Budding with genetic recombination
13. What is the primary function of bacterial ribosomes in the 70S
configuration?
A. Protein synthesis
B. DNA replication
C. ATP synthesis
D. Lipid metabolism
14. Which environmental condition defines an obligate anaerobe?
A. Cannot survive in the presence of oxygen
B. Requires only trace oxygen
C. Requires oxygen to survive
D. Grows equally well with or without oxygen
15. Facultative anaerobes are best described as organisms that:
A. Only grow at high CO2 concentrations
B. Die immediately when exposed to oxygen
C. Can grow with or without oxygen, preferring oxygen when available
D. Require strict anaerobic conditions
16. The lag phase of a bacterial growth curve is characterized by:
A. Death exceeding new cell formation
B. Metabolic adaptation with minimal cell division
C. Depletion of nutrients causing rapid death
D. Exponential increase in cell number
17. During which phase of bacterial growth does cell division occur at a
constant, maximal rate?
A. Death phase
Page 3 of 36
, B. Log (exponential) phase
C. Stationary phase
D. Lag phase
18. The stationary phase of bacterial growth occurs primarily because of:
A. Endospore germination
B. Optimal nutrient availability
C. Nutrient depletion and waste accumulation
D. Genetic mutation rates increasing
19. Which term describes bacteria that require an external source of organic
carbon for energy?
A. Chemolithotrophs
B. Autotrophs
C. Photoautotrophs
D. Heterotrophs
20. Obligate intracellular bacteria such as Rickettsia and Chlamydia are
unable to survive outside host cells because they:
A. Cannot undergo binary fission
B. Lack a cell wall
C. Lack the ability to produce their own ATP
D. Lack ribosomes
21. Which of the following best describes bacterial plasmids?
A. Structural cell wall proteins
B. RNA molecules used for translation
C. Linear chromosomal DNA
D. Small, circular, extrachromosomal DNA that often carries antibiotic
resistance genes
22. Transformation in bacterial genetics refers to:
A. Spontaneous mutation of existing DNA
B. Uptake of naked DNA from the environment
C. Transfer of DNA via a bacteriophage
D. Direct cell-to-cell contact via a pilus
23. Bacterial conjugation requires which structure to transfer genetic material
between cells?
Page 4 of 36
