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Questions and Answers
Which of the following Gram-Negative Bacteria is Oxidase +?
Which of the following Gram-Negative Bacteria is Oxidase +?
Which of the following Gram-Negative Bacteria is Lactose +?
Which of the following Gram-Negative Bacteria is Lactose +?
What is the shape of Vibrio?
What is the shape of Vibrio?
Which of the following Gram-Negative Bacteria grows at 42°C in alkaline media?
Which of the following Gram-Negative Bacteria grows at 42°C in alkaline media?
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Which Gram-Negative Bacteria is Oxidase -?
Which Gram-Negative Bacteria is Oxidase -?
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Which of the following Gram-Negative Bacteria is a Diplococci?
Which of the following Gram-Negative Bacteria is a Diplococci?
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What characterizes eukaryotic cells?
What characterizes eukaryotic cells?
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What is the main focus of bacteriology?
What is the main focus of bacteriology?
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What is the size range of objects that are too small to be visible with the naked eye?
What is the size range of objects that are too small to be visible with the naked eye?
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Which of the following is NOT a type of eukaryote?
Which of the following is NOT a type of eukaryote?
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What is the term for the study of all living organisms that are too small to be visible with the naked eye?
What is the term for the study of all living organisms that are too small to be visible with the naked eye?
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Which of the following is a type of acellular organism?
Which of the following is a type of acellular organism?
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What is the function of Lipid A in the lipopolysaccharide (LPS) of Gram-negative bacteria?
What is the function of Lipid A in the lipopolysaccharide (LPS) of Gram-negative bacteria?
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What is the component of peptidoglycan that is responsible for its cross-linking?
What is the component of peptidoglycan that is responsible for its cross-linking?
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What is the target of β-lactam drugs, including penicillin?
What is the target of β-lactam drugs, including penicillin?
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How many ATP molecules are generated during the metabolism of one glucose molecule in prokaryotes?
How many ATP molecules are generated during the metabolism of one glucose molecule in prokaryotes?
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What is the main difference between the metabolism of eukaryotes and prokaryotes?
What is the main difference between the metabolism of eukaryotes and prokaryotes?
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What is the characteristic of Gram-positive bacteria?
What is the characteristic of Gram-positive bacteria?
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Which of the following features is characteristic of eukaryotic cells?
Which of the following features is characteristic of eukaryotic cells?
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What is the purpose of the Gram stain method in microbiology?
What is the purpose of the Gram stain method in microbiology?
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What is the function of the peptidoglycan layer in Gram-positive bacteria?
What is the function of the peptidoglycan layer in Gram-positive bacteria?
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What is the main component of the outer membrane in Gram-negative bacteria?
What is the main component of the outer membrane in Gram-negative bacteria?
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What is the primary function of porins in Gram-negative bacteria?
What is the primary function of porins in Gram-negative bacteria?
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Which of the following is a characteristic of Gram-positive bacteria?
Which of the following is a characteristic of Gram-positive bacteria?
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What is microbiology?
What is microbiology?
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What is bacteriology?
What is bacteriology?
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Eukaryotes are single-celled organisms that have a distinct nucleus with a membrane.
Eukaryotes are single-celled organisms that have a distinct nucleus with a membrane.
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What is the main difference between prokaryotes and eukaryotes?
What is the main difference between prokaryotes and eukaryotes?
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What is the purpose of Gram staining?
What is the purpose of Gram staining?
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What is the function of peptidoglycan in bacterial cell walls?
What is the function of peptidoglycan in bacterial cell walls?
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What is the primary function of lipopolysaccharides (LPS) in Gram-negative bacteria?
What is the primary function of lipopolysaccharides (LPS) in Gram-negative bacteria?
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What is the role of transpeptidases in bacterial cell wall synthesis?
What is the role of transpeptidases in bacterial cell wall synthesis?
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What is the significance of ATP production in microbial metabolism?
What is the significance of ATP production in microbial metabolism?
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Match the following Gram-positive bacteria with their characteristic shapes:
Match the following Gram-positive bacteria with their characteristic shapes:
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Match the following Gram-negative bacteria with their characteristic features:
Match the following Gram-negative bacteria with their characteristic features:
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Study Notes
Bacteriology
- Eukaryotes are organisms with cells that have a nucleus enclosed within a nuclear envelope.
- Prokaryotes are single-celled organisms that lack a distinct nucleus with a membrane and other specialized organelles.
Microbiology
- Microbiology is the study of all living organisms that are too small to be visible with the naked eye.
- Bacteriology is the study of bacteria.
Scope of Microbiology
- Microbiology encompasses the study of cellular organisms (bacteria, archaea, fungi, algae, protozoa, and helminths) and acellular entities (viruses, viroids, and prions).
Prokaryotes vs. Eukaryotes
- Prokaryotes lack a true nucleus and membrane-bound organelles.
- Eukaryotes have a true nucleus and membrane-bound organelles.
Gram-Negative Bacteria
- Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane containing lipopolysaccharides (endotoxins).
- Examples of Gram-negative bacteria include Hemophilus, Bartonella, Pasteurella, Neisseria, Francisella, and Escherichia coli.
Bacterial Structure
- Prokaryotes have a peptidoglycan (murein) layer in their cell wall, composed of repeating units of N-acetylmuramic acid and N-acetylglucosamine.
- The peptidoglycan layer is cross-linked by trans-peptide bridges.
Bacterial Replication
- Cell wall targeting involves the incorporation of peptidoglycan monomers into the existing cell wall matrix, catalyzed by transpeptidases or penicillin-binding proteins (PBPs).
- PBPs are major drug targets for β-lactam antibiotics, including penicillin.
Microbial Metabolism
- Metabolism is the powerhouse of organisms, generating energy and synthesizing molecules.
- Prokaryotes generate 38 ATP, while eukaryotes generate 36 ATP.
Industrial and Laboratory Use of Microbial Metabolism
- Microbial metabolism is used in industrial processes, such as biofuel production, and in laboratory research, such as protein production.
Gram-Positive Bacteria
- Gram-positive bacteria have a thick peptidoglycan layer and teichoic acid.
- Examples of Gram-positive bacteria include Bacillus, Listeria, Clostridium, and Streptococcus.
Gram Stain Method
- Gram staining is a method of classifying bacteria based on their shape and color.
- The process involves heat fixing bacteria, staining with crystal violet, applying iodine, de-staining with alcohol, and counter-staining with Pink Safranin.
Gram Stain and Peptidoglycan
- The peptidoglycan layer of Gram-positive bacteria retains the crystal violet stain, while Gram-negative bacteria do not.
Bacterial Cell Structure
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Gram-positive bacteria have a thick peptidoglycan layer, teichoic acid, and lipoteichoic acid.
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Gram-negative bacteria have a thin peptidoglycan layer, an outer membrane, porins, and lipopolysaccharides.### Basic Bacteriology
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Eukaryotes are organisms whose cells have a nucleus enclosed within a nuclear envelope.
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Prokaryotes are single-celled organisms that lack a distinct nucleus with a membrane and other specialized organelles.
Microbiology and Bacteriology
- Microbiology is the study of all living organisms that are too small to be visible with the naked eye.
- Bacteriology is the study of bacteria.
Scope of Microbiology
- Cellular: Prokaryotes (bacteria, archaea), Eukaryotes (fungi, algae, protozoa, helminths)
- Acellular: Viruses, viroids, prions
Prokaryotes vs. Eukaryotes
- Prokaryotes: • 70s Ribosome (50s and 30s subunits) • Single circular genome • Plasmids (e.g., antimicrobial resistance genes) • No membrane-bound organelles
- Eukaryotes: • 80s Ribosome (60s and 40s subunits) • Multiple chromosomes • Linear genome • Membrane-bound organelles (e.g., nucleus, ER)
Bacterial Structure
- Cell morphology helps classify bacteria
- Gram staining pattern is also used for classification: • Gram-Positive • Gram-Negative • Atypicals
Gram Stain Method
- Bacteria are classified by shape and color using Gram stain procedure
- Steps: • Heat fix bacteria on a glass slide • Stain bacteria with crystal violet • Apply iodine as a mordant to the crystal violet • De-stain bacteria with alcohol • Counter-stain with Pink Safranin
Gram Stain and Peptidoglycan
- Gram Positive: Peptidoglycan layer retains the crystal violet of the Gram stain
- Gram Negative: Thin peptidoglycan layer, outer membrane, porins, and lipopolysaccharide
Bacterial Cell Structure
- Gram Positive Features: • Thick peptidoglycan layer • Teichoic acid • LipoTeichoic acid
- Gram Negative Features: • Thin peptidoglycan layer • Outer membrane • Porins • Lipopolysaccharide (LPS)
Gram-Negative Cell Wall: LPS
- LPS is part of the outer membrane
- Only found on Gram-negative bacteria
- LPS has 3 units: • "O" antigen (polysaccharide, somatic antigen for species identification) • Core polysaccharide • Lipid A (toxic effect, triggers inflammation leading to sepsis)
Cell Wall - Peptidoglycan
- Peptidoglycan monomer is composed of: • NAM (n-acetylmuramic acid) • NAG (n-acetylglucosamine) • Pentapeptide chain (5 amino acids)
- Peptidoglycan layer is composed of repeating subunits of NAG and NAM, crosslinked by sugars and trans-peptide bridges
Cell Wall Targeting
- Transpeptidases or Penicillin-Binding Proteins (PBPs) catalyze the incorporation of the monomer into the existing peptidoglycan wall matrix
- PBPs are major drug targets for β-lactam drugs, including penicillin
Microbial Metabolism
- Metabolism: Powerhouse of organisms
- 36 ATP (Eukaryotes) vs. 38 ATP (Prokaryotes)
- Examples of microbial metabolism: • Industrial use • Laboratory use
Human Pathogens
- Gram-Positive Bacteria: • Bacilli (e.g., Listeria, Bacillus) • Cocci (e.g., Streptococcus, Staphylococcus)
- Gram-Negative Bacteria: • Diplococci (e.g., Neisseria) • Coccobacilli (e.g., Hemophilus) • Bacilli (e.g., Escherichia coli, Klebsiella) • Comma-shaped (e.g., Vibrio, Helicobacter)
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Description
This quiz covers the basics of bacteriology, focusing on the differences between eukaryotes and prokaryotes. Learn about the characteristics of these cell types and test your knowledge.
