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Questions and Answers
What is a characteristic feature of Pseudomonas aeruginosa?
What is a characteristic feature of Pseudomonas aeruginosa?
Which pigment is associated with Serratia marcescens?
Which pigment is associated with Serratia marcescens?
What is a primary metabolite produced during the logarithmic phase of growth?
What is a primary metabolite produced during the logarithmic phase of growth?
Which biochemical test differentiates Staphylococci from Streptococci?
Which biochemical test differentiates Staphylococci from Streptococci?
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What type of metabolic processes are secondary metabolites primarily involved in?
What type of metabolic processes are secondary metabolites primarily involved in?
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What is the role of clavulanic acid in relation to antibiotics?
What is the role of clavulanic acid in relation to antibiotics?
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Which bacteria is known for being a source of monosodium glutamate (MSG)?
Which bacteria is known for being a source of monosodium glutamate (MSG)?
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What feature is primarily associated with the mechanism of bacterial conjugation?
What feature is primarily associated with the mechanism of bacterial conjugation?
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Which of the following best describes the term 'nosocomial infection'?
Which of the following best describes the term 'nosocomial infection'?
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What result does exposing enzymes to temperatures between 56°C and 60°C generally have?
What result does exposing enzymes to temperatures between 56°C and 60°C generally have?
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Which of the following antibiotics is classified as a beta-lactam?
Which of the following antibiotics is classified as a beta-lactam?
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What component in bacterial spores is utilized for resistance?
What component in bacterial spores is utilized for resistance?
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What occurs to a vegetative cell during starvation that leads to spore formation?
What occurs to a vegetative cell during starvation that leads to spore formation?
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Which of the following statements about eukaryotic cells is correct?
Which of the following statements about eukaryotic cells is correct?
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What is the primary component of the cell wall in Gram-positive bacteria?
What is the primary component of the cell wall in Gram-positive bacteria?
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How much ATP is produced per glucose molecule in eukaryotic cells?
How much ATP is produced per glucose molecule in eukaryotic cells?
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Which characteristic differentiates Gram-negative bacteria from Gram-positive bacteria?
Which characteristic differentiates Gram-negative bacteria from Gram-positive bacteria?
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What type of DNA structure is found in prokaryotic cells?
What type of DNA structure is found in prokaryotic cells?
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Which of the following is NOT true regarding ribosomes in eukaryotic cells?
Which of the following is NOT true regarding ribosomes in eukaryotic cells?
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What role do teichoic acids play in Gram-positive bacteria?
What role do teichoic acids play in Gram-positive bacteria?
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What is the typical thickness of the peptidoglycan layer in Gram-positive bacteria?
What is the typical thickness of the peptidoglycan layer in Gram-positive bacteria?
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What stain is used initially to detect Mycobacterium?
What stain is used initially to detect Mycobacterium?
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What type of culture medium is primarily used for the isolation of fastidious bacteria?
What type of culture medium is primarily used for the isolation of fastidious bacteria?
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What color indicates a positive acid-fast result?
What color indicates a positive acid-fast result?
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Which of the following bacteria is a non-sugar fermenter?
Which of the following bacteria is a non-sugar fermenter?
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What is the function of phenol in the staining process?
What is the function of phenol in the staining process?
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What does a blackening of the medium indicate when testing for hydrogen sulfide production?
What does a blackening of the medium indicate when testing for hydrogen sulfide production?
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Which Gram reaction would indicate a bacilli shape and be arranged in clusters?
Which Gram reaction would indicate a bacilli shape and be arranged in clusters?
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What is the purpose of bile salts and crystal violet in McConkey agar?
What is the purpose of bile salts and crystal violet in McConkey agar?
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What type of hemolysis is characterized by greenish discoloration on blood agar plates?
What type of hemolysis is characterized by greenish discoloration on blood agar plates?
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Which of the following methods is specifically used for detecting E. coli?
Which of the following methods is specifically used for detecting E. coli?
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What type of bacteria does thiosulfate-citrate-bile salt-sucrose agar target?
What type of bacteria does thiosulfate-citrate-bile salt-sucrose agar target?
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Which type of dye is attracted to the negative sialic acid on bacterial cell surfaces?
Which type of dye is attracted to the negative sialic acid on bacterial cell surfaces?
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What is the predominant feature of the beta hemolytic pattern on blood agar?
What is the predominant feature of the beta hemolytic pattern on blood agar?
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What can occur if reactive oxygen species (ROS) accumulate in bacteria?
What can occur if reactive oxygen species (ROS) accumulate in bacteria?
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Which bacteria is known for causing cutaneous anthrax when it penetrates the skin?
Which bacteria is known for causing cutaneous anthrax when it penetrates the skin?
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What is the primary function of catalase and peroxidase in obligate aerobes?
What is the primary function of catalase and peroxidase in obligate aerobes?
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Study Notes
Microbial Cell Structure
- Microorganisms classified into two domains: eukaryotes (with a nucleus) and prokaryotes (without a true nucleus).
- Bacterial cell wall differs between gram-positive (20-25nm thick, 50%-90% peptidoglycan) and gram-negative (11-15nm thick, 10% peptidoglycan).
- Gram-negative bacteria have an outer membrane containing lipopolysaccharides, while gram-positive do not.
ATP Production
- Eukaryotic ATP production occurs in mitochondria (36 ATP per glucose).
- Prokaryotes produce 38 ATP per glucose, utilizing their cell membrane.
Ribosomal and DNA Characteristics
- Eukaryotic ribosomes consist of 80S (60S large subunit, 40S small subunit); prokaryotic ribosomes are 70S (50S large subunit, 30S small subunit).
- Eukaryotic DNA is linear and associated with histones; prokaryotic DNA is circular and lacks histones.
Antibiotic and Resistance Considerations
- Overuse of antibiotics leads to increased bacterial resistance; antibiotic residue-free poultry helps prevent this.
- Clavulanic acid can inhibit bacterial enzymes that degrade antibiotics.
Applications of Bacteria
- Lactic acid bacteria play a role in food fermentation and preservation.
- Corynebacterium species are sources of MSG but can also cause disease (e.g., C. diphtheriae).
Bacterial Structures
- Pili are hair-like appendages used for cell attachment and DNA transfer via conjugation.
- Endospores ensure bacterial survival in harsh conditions, containing calcium dipicolinate.
Metabolite Distinction
- Primary metabolites are essential for basic metabolic growth (e.g., alcohol, amino acids).
- Secondary metabolites serve defense functions (e.g., antibiotics like penicillin).
Biochemical Testing
- Catalase test differentiates Staphylococci (positive) from Streptococci (negative).
- Tuberculosis detection requires specific staining methods (e.g., carbol fuchsin).
Culture Media Types
- Primary isolation mediums are simple; enriched mediums aid in isolating fastidious bacteria.
- Differential mediums, like McConkey agar, are used to distinguish between lactose fermenters and non-fermenters.
Bacterial Physiology and Oxygen Needs
- Obligate aerobes possess enzymes to degrade toxic reactive oxygen species, preventing accumulation of harmful metabolites.
- Excessive oxygen can cause blindness due to toxic oxygen metabolites.
Bacterial Identification
- Gram staining reveals cell shape and arrangement, crucial for identifying different bacterial strains, such as cocci (spherical) or bacilli (rod-shaped).
Dyes in Microbiology
- Dyes can be positively charged and adhere to negative cell surfaces, aiding in bacterial identification (e.g., methylene blue, crystal violet).
- Dyes stain differently based on cell properties and can assist in visual differentiation in culture.
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Description
This quiz covers essential topics in microbial cell biology, focusing on the differences between eukaryotic and prokaryotic cells. It explores cell structure, ATP production, ribosomal characteristics, and the implications of antibiotic use. Test your knowledge of how these organisms function and interact with their environments.
