Introduction to Microbiology

Question 1

What is microbiology?
A) The study of bacteria only
B) The study of microorganisms too small to be seen with the naked eye
C) The study of viruses only
D) The study of animal and plant cells

Answer 1

B

Question 2

Which of the following is NOT a branch of microbiology?
A) Bacteriology
B) Virology
C) Botany
D) Mycology

Answer 2

C

Question 2

Which scientist first observed bacteria using a simple microscope?
A) Robert Koch
B) Louis Pasteur
C) Antonie van Leeuwenhoek
D) Edward Jenner

Answer 2

C

Question 2

Which of the following structures is found in prokaryotic cells but NOT in eukaryotic cells?
A) Nucleus
B) Mitochondria
C) Circular DNA
D) Endoplasmic reticulum

Answer 2

C

Question 3

What is the key difference between prokaryotic and eukaryotic ribosomes?
A) Prokaryotic ribosomes are larger (80S)
B) Prokaryotic ribosomes are smaller (70S)
C) Eukaryotic ribosomes have no RNA

Answer 3

B

Question 4

Which staining technique differentiates bacteria based on cell wall composition?
A) Acid-fast stain
B) Gram stain
C) Endospore stain
D) Capsule stain

Answer 4

B

Question 5

Which of the following is a characteristic of Gram-positive bacteria?
A) Thin peptidoglycan layer
B) Outer membrane containing lipopolysaccharides (LPS)
C) Thick peptidoglycan layer
D) Resistance to antibiotics like penicillin

Answer 5

C

Question 6

What structure allows bacteria to adhere to surfaces?
A) Ribosomes
B) Pili
C) Plasmids
D) Nucleus

Answer 6

B

Question 7

What type of bacterial arrangement describes chains of spherical cells?
A) Streptococci
B) Staphylococci
C) Sarcina
D) Bacilli

Answer 7

A

Question 8

What is the function of bacterial endospores?
A) Oxygen production
B) Protection against harsh conditions
C) Energy storage
D) Antibiotic resistance

Answer 8

B

Question 9

Which bacterial structure is responsible for motility?
A) Fimbriae
B) Plasmids
C) Flagella
D) Ribosomes

Answer 9

C

Question 10

What is the primary function of bacterial plasmids?
A) Protein synthesis
B) Genetic exchange and antibiotic resistance
C) Energy production
D) DNA replication

Answer 10

B

Question 11

Which staining technique is used to identify bacteria with waxy cell walls?
A) Gram stain
B) Acid-fast stain
C) Capsule stain
D) Negative stain

Answer 11

B

Question 12

Which bacterial genus is known for its acid-fast properties?
A) Staphylococcus
B) Streptococcus
C) Mycobacterium
D) Escherichia

Answer 12

C

Question 13

What is the primary function of bacterial capsules?
A) Protection against phagocytosis
B) Energy production
C) Protein synthesis
D) Motility

Answer 13

A

Question 14

What is the main difference between Gram-negative and Gram-positive bacteria?
A) Gram-negative bacteria lack a cell wall
B) Gram-negative bacteria have an outer membrane
C) Gram-positive bacteria contain DNA
D) Gram-positive bacteria lack peptidoglycan

Answer 14

B

Question 15

What type of bacterial reproduction involves DNA transfer through pili?
A) Binary fission
B) Conjugation
C) Transduction
D) Transformation

Answer 15

B

Question 16

What is the function of LPS in Gram-negative bacteria?
A) Forms the peptidoglycan layer
B) Provides structural integrity and protection
C) Enables DNA replication
D) Promotes protein synthesis

Answer 16

B

Question 17

What type of stain is used to visualize bacterial capsules?
A) Gram stain
B) Endospore stain
C) Negative stain
D) Acid-fast stain

Answer 17

C

Question 18

What is the primary mode of bacterial replication?
A) Mitosis
B) Binary fission
C) Meiosis
D) Budding

Answer 18

B

Question 19

A patient presents with tuberculosis. Which staining method is used for diagnosis?
A) Gram stain
B) Acid-fast stain
C) Capsule stain
D) Endospore stain

Answer 19

B

Question 19

A bacteria resistant to heat and disinfectants is most likely forming which structure?
A) Capsule
B) Endospore
C) Plasmid
D) Flagella

Answer 19

B

Question 19

A sample contains Gram-positive cocci in clusters. Which bacterium is most likely?
A) Escherichia coli
B) Mycobacterium tuberculosis
C) Staphylococcus aureus
D) Clostridium tetani

Answer 19

C

Question 19

A patient is diagnosed with botulism. Which bacterial genus is responsible?
A) Escherichia
B) Clostridium
C) Bacillus
D) Mycobacterium

Answer 19

B

Question 20

Which bacterial feature contributes to antibiotic resistance? A) Flagella B) Capsule C) Plasmids D) Ribosomes

Answer 20

C

Question 21

What is the purpose of Koch’s postulates? A) To classify bacteria B) To establish a microorganism as the cause of a disease C) To identify antibiotic resistance genes D) To study bacterial reproduction

Answer 21

B

Question 22

A bacterial strain survives boiling water. What adaptation does it likely possess? A) Thick peptidoglycan B) Capsule formation C) Endospore formation D) Conjugation ability

Answer 22

C

Question 23

A hospital outbreak of pneumonia is linked to a Gram-negative, capsule-forming bacterium. Which genus is the likely culprit? A) Staphylococcus B) Mycobacterium C) Klebsiella D) Clostridium

Answer 23

C

Question 24

Which of the following correctly describes a major difference between prokaryotic and eukaryotic cells? A) Only eukaryotic cells have ribosomes B) Prokaryotic cells have a membrane-bound nucleus C) Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not D) Prokaryotic cells undergo mitosis for reproduction

Answer 24

C

Question 25

Which type of microscope is commonly used to visualize bacteria in the laboratory? A) Electron microscope B) Phase-contrast microscope C) Fluorescence microscope D) Light microscope

Answer 25

D

Question 26

What is the primary function of the bacterial cell wall? A) ATP production B) DNA replication C) Providing structural support and protection D) Facilitating protein synthesis

Answer 26

C

Question 27

Which of the following statements about bacterial ribosomes is correct? A) They are 80S ribosomes like in eukaryotic cells B) They function in lipid biosynthesis C) They are composed of 70S ribosomes with 50S and 30S subunits D) They are located in the nucleus of bacteria

Answer 27

C

Question 28

Which bacterial shape describes spherical bacteria arranged in clusters? A) Staphylococci B) Streptobacilli C) Spirilla D) Diplococci

Answer 28

A

Question 29

Which of the following structures is unique to Gram-negative bacteria? A) Peptidoglycan B) Teichoic acid C) Lipopolysaccharide (LPS) D) Capsule

Answer 29

C

Question 30

Which bacterial growth phase is characterized by an adaptation period before active cell division begins? A) Lag phase B) Log phase C) Stationary phase D) Death phase

Answer 30

A

Question 31

Which of the following is a characteristic of obligate anaerobes? A) They grow only in the presence of oxygen B) They are killed by oxygen exposure C) They can switch between aerobic and anaerobic metabolism D) They require CO₂ for growth

Answer 31

B

Question 32

Which type of microorganism thrives in extremely high salt concentrations? A) Thermophiles B) Acidophiles C) Halophiles D) Psychrophiles

Answer 32

C

Question 33

Which metabolic pathway is NOT involved in glucose metabolism in bacteria? A) Glycolysis B) TCA cycle C) Pentose phosphate pathway D) Urea cycle

Answer 33

D

Question 34

Organisms that obtain carbon from CO₂ are called: A) Heterotrophs B) Autotrophs C) Phototrophs D) Chemotrophs

Answer 34

B

Question 35

A bacterium that can survive with or without oxygen is called: A) Obligate aerobe B) Obligate anaerobe C) Facultative anaerobe D) Microaerophile

Answer 35

C

Question 35

In which phase does the rate of bacterial cell division equal the rate of cell death? A) Lag phase B) Log phase C) Stationary phase D) Death phase

Answer 35

C

Question 36

Mycobacterium tuberculosis is classified as a(n): A) Obligate anaerobe B) Facultative anaerobe C) Obligate aerobe D) Aerotolerant anaerobe

Answer 36

C

Question 37

Thioglycolate broth is used to: A) Detect motility B) Determine oxygen requirements C) Identify Gram-positive bacteria D) Isolate fungi

Answer 37

B

Question 37

Biofilms are often associated with: A) Increased antibiotic resistance B) Decreased bacterial survival C) Rapid bacterial death D) High oxygen environments

Answer 37

A

Question 37

What is a biofilm? A) A single layer of bacteria B) A polysaccharide-encased community of bacteria C) A method for culturing bacteria D) A virus-infected bacterial cell

Answer 37

B

Question 38

In which phase does the rate of bacterial cell division equal the rate of cell death? A) Lag phase B) Log phase C) Stationary phase D) Death phase

Answer 38

C