Bacteriology Lecture 3: Eukaryotes and Prokaryotes
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Questions and Answers

Which of the following Gram-Negative Bacteria is Oxidase +?

  • Pseudomonas (correct)
  • Shigella
  • Campylobacter (correct)
  • Escherichia coli
  • Which of the following Gram-Negative Bacteria is Lactose +?

  • Escherichia coli (correct)
  • Klebsiella (correct)
  • Salmonella
  • Shigella
  • What is the shape of Vibrio?

  • Bacilli
  • Coccobacilli
  • Diplococci
  • Comma-shaped (correct)
  • Which of the following Gram-Negative Bacteria grows at 42°C in alkaline media?

    <p>Campylobacter</p> Signup and view all the answers

    Which Gram-Negative Bacteria is Oxidase -?

    <p>Enterobacter</p> Signup and view all the answers

    Which of the following Gram-Negative Bacteria is a Diplococci?

    <p>Neisseria</p> Signup and view all the answers

    What characterizes eukaryotic cells?

    <p>The presence of a distinct nucleus with a membrane</p> Signup and view all the answers

    What is the main focus of bacteriology?

    <p>The study of bacteria</p> Signup and view all the answers

    What is the size range of objects that are too small to be visible with the naked eye?

    <p>0.2-2uM</p> Signup and view all the answers

    Which of the following is NOT a type of eukaryote?

    <p>Bacteria</p> Signup and view all the answers

    What is the term for the study of all living organisms that are too small to be visible with the naked eye?

    <p>Microbiology</p> Signup and view all the answers

    Which of the following is a type of acellular organism?

    <p>Viruses</p> Signup and view all the answers

    What is the function of Lipid A in the lipopolysaccharide (LPS) of Gram-negative bacteria?

    <p>It triggers inflammation leading to sepsis</p> Signup and view all the answers

    What is the component of peptidoglycan that is responsible for its cross-linking?

    <p>Trans-peptide bridges</p> Signup and view all the answers

    What is the target of β-lactam drugs, including penicillin?

    <p>Penicillin-Binding Proteins (PBPs)</p> Signup and view all the answers

    How many ATP molecules are generated during the metabolism of one glucose molecule in prokaryotes?

    <p>38 ATP</p> Signup and view all the answers

    What is the main difference between the metabolism of eukaryotes and prokaryotes?

    <p>Number of ATP molecules generated</p> Signup and view all the answers

    What is the characteristic of Gram-positive bacteria?

    <p>Thick peptidoglycan layer</p> Signup and view all the answers

    Which of the following features is characteristic of eukaryotic cells?

    <p>Multiple linear chromosomes</p> Signup and view all the answers

    What is the purpose of the Gram stain method in microbiology?

    <p>To classify bacteria based on their staining pattern</p> Signup and view all the answers

    What is the function of the peptidoglycan layer in Gram-positive bacteria?

    <p>To retain the crystal violet of the Gram stain</p> Signup and view all the answers

    What is the main component of the outer membrane in Gram-negative bacteria?

    <p>Lipopolysaccharide (LPS)</p> Signup and view all the answers

    What is the primary function of porins in Gram-negative bacteria?

    <p>To regulate the transport of molecules across the cell membrane</p> Signup and view all the answers

    Which of the following is a characteristic of Gram-positive bacteria?

    <p>Teichoic acid</p> Signup and view all the answers

    What is microbiology?

    <p>the study of all living organisms that are too small to be visible with the naked eye</p> Signup and view all the answers

    What is bacteriology?

    <p>the study of bacteria</p> Signup and view all the answers

    Eukaryotes are single-celled organisms that have a distinct nucleus with a membrane.

    <p>False</p> Signup and view all the answers

    What is the main difference between prokaryotes and eukaryotes?

    <p>Eukaryotes have a nucleus, while prokaryotes do not.</p> Signup and view all the answers

    What is the purpose of Gram staining?

    <p>to classify bacteria by shape and color</p> Signup and view all the answers

    What is the function of peptidoglycan in bacterial cell walls?

    <p>to provide structural support and maintain cell shape</p> Signup and view all the answers

    What is the primary function of lipopolysaccharides (LPS) in Gram-negative bacteria?

    <p>to trigger inflammation and sepsis</p> Signup and view all the answers

    What is the role of transpeptidases in bacterial cell wall synthesis?

    <p>to catalyze the incorporation of peptidoglycan monomers into the existing cell wall</p> Signup and view all the answers

    What is the significance of ATP production in microbial metabolism?

    <p>it provides energy for cellular processes</p> Signup and view all the answers

    Match the following Gram-positive bacteria with their characteristic shapes:

    <p>Bacillus = Rod-shaped Cocci = Spherical Streptococcus = Chain-like Corynebacterium = Club-shaped</p> Signup and view all the answers

    Match the following Gram-negative bacteria with their characteristic features:

    <p>Escherichia coli = Lactose-fermenting Pseudomonas = Oxidase-positive Salmonella = Lactose-negative Vibrio = Comma-shaped</p> Signup and view all the answers

    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

    • Gram-positive bacteria have a thick peptidoglycan layer, teichoic acid, and lipoteichoic acid.

    • Gram-negative bacteria have a thin peptidoglycan layer, an outer membrane, porins, and lipopolysaccharides.### Basic Bacteriology

    • Eukaryotes are organisms whose cells 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 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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    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.

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