Introduction to Microbiology Flashcards
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
B
Which of the following is NOT a branch of microbiology?
A) Bacteriology
B) Virology
C) Botany
D) Mycology
C
Which scientist first observed bacteria using a simple microscope?
A) Robert Koch
B) Louis Pasteur
C) Antonie van Leeuwenhoek
D) Edward Jenner
C
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
C
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
B
Which staining technique differentiates bacteria based on cell wall composition?
A) Acid-fast stain
B) Gram stain
C) Endospore stain
D) Capsule stain
B
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
C
What structure allows bacteria to adhere to surfaces?
A) Ribosomes
B) Pili
C) Plasmids
D) Nucleus
B
What type of bacterial arrangement describes chains of spherical cells?
A) Streptococci
B) Staphylococci
C) Sarcina
D) Bacilli
A
What is the function of bacterial endospores?
A) Oxygen production
B) Protection against harsh conditions
C) Energy storage
D) Antibiotic resistance
B
Which bacterial structure is responsible for motility?
A) Fimbriae
B) Plasmids
C) Flagella
D) Ribosomes
C
What is the primary function of bacterial plasmids?
A) Protein synthesis
B) Genetic exchange and antibiotic resistance
C) Energy production
D) DNA replication
B
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
B
Which bacterial genus is known for its acid-fast properties?
A) Staphylococcus
B) Streptococcus
C) Mycobacterium
D) Escherichia
C
What is the primary function of bacterial capsules?
A) Protection against phagocytosis
B) Energy production
C) Protein synthesis
D) Motility
A
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
B
What type of bacterial reproduction involves DNA transfer through pili?
A) Binary fission
B) Conjugation
C) Transduction
D) Transformation
B
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
B
What type of stain is used to visualize bacterial capsules?
A) Gram stain
B) Endospore stain
C) Negative stain
D) Acid-fast stain
C
What is the primary mode of bacterial replication?
A) Mitosis
B) Binary fission
C) Meiosis
D) Budding
B
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
B
A bacteria resistant to heat and disinfectants is most likely forming which structure?
A) Capsule
B) Endospore
C) Plasmid
D) Flagella
B
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
C
A patient is diagnosed with botulism. Which bacterial genus is responsible?
A) Escherichia
B) Clostridium
C) Bacillus
D) Mycobacterium
B
Which bacterial feature contributes to antibiotic resistance?
A) Flagella
B) Capsule
C) Plasmids
D) Ribosomes
C
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
B
A bacterial strain survives boiling water. What adaptation does it likely possess?
A) Thick peptidoglycan
B) Capsule formation
C) Endospore formation
D) Conjugation ability
C
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
C
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
C
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
D
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
C
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
C
Which bacterial shape describes spherical bacteria arranged in clusters?
A) Staphylococci
B) Streptobacilli
C) Spirilla
D) Diplococci
A
Which of the following structures is unique to Gram-negative bacteria?
A) Peptidoglycan
B) Teichoic acid
C) Lipopolysaccharide (LPS)
D) Capsule
C
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
A
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
B
Which type of microorganism thrives in extremely high salt concentrations?
A) Thermophiles
B) Acidophiles
C) Halophiles
D) Psychrophiles
C
Which metabolic pathway is NOT involved in glucose metabolism in bacteria?
A) Glycolysis
B) TCA cycle
C) Pentose phosphate pathway
D) Urea cycle
D
Organisms that obtain carbon from CO₂ are called:
A) Heterotrophs
B) Autotrophs
C) Phototrophs
D) Chemotrophs
B
A bacterium that can survive with or without oxygen is called:
A) Obligate aerobe
B) Obligate anaerobe
C) Facultative anaerobe
D) Microaerophile
C
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
C
Mycobacterium tuberculosis is classified as a(n):
A) Obligate anaerobe
B) Facultative anaerobe
C) Obligate aerobe
D) Aerotolerant anaerobe
C
Thioglycolate broth is used to:
A) Detect motility
B) Determine oxygen requirements
C) Identify Gram-positive bacteria
D) Isolate fungi
B
Biofilms are often associated with:
A) Increased antibiotic resistance
B) Decreased bacterial survival
C) Rapid bacterial death
D) High oxygen environments
A
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
B
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
C
