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Questions and Answers
What is the primary electron acceptor in anaerobic respiration?
What is the primary electron acceptor in anaerobic respiration?
What is the correct sequence of events in the Lac operon? (Note: only the essential events are listed.)
What is the correct sequence of events in the Lac operon? (Note: only the essential events are listed.)
Which of the following is NOT a characteristic of obligate anaerobes?
Which of the following is NOT a characteristic of obligate anaerobes?
What is the primary function of the Krebs cycle?
What is the primary function of the Krebs cycle?
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Which of the following is NOT a method for determining bacterial cell numbers?
Which of the following is NOT a method for determining bacterial cell numbers?
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What is the role of β-galactosidase permease in lactose fermentation?
What is the role of β-galactosidase permease in lactose fermentation?
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Which of the following is considered an extrachromosomal element?
Which of the following is considered an extrachromosomal element?
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What is the difference between the genotype and phenotype of a bacterium?
What is the difference between the genotype and phenotype of a bacterium?
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What is the primary role of a clinical microbiologist?
What is the primary role of a clinical microbiologist?
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Which of the following structures differentiates prokaryotes from eukaryotes?
Which of the following structures differentiates prokaryotes from eukaryotes?
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Which category do unicellular organisms with flagella, pseudopodia, or cilia belong to?
Which category do unicellular organisms with flagella, pseudopodia, or cilia belong to?
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What form do multicellular fungi typically take?
What form do multicellular fungi typically take?
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How do yeasts reproduce?
How do yeasts reproduce?
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Which of the following is NOT a nutritional requirement for bacterial growth?
Which of the following is NOT a nutritional requirement for bacterial growth?
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What type of growth media is specifically designed to suppress the growth of certain bacteria while allowing the growth of others?
What type of growth media is specifically designed to suppress the growth of certain bacteria while allowing the growth of others?
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Which staining method is commonly used to identify acid-fast bacteria?
Which staining method is commonly used to identify acid-fast bacteria?
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Psychrophiles are bacteria that thrive at what temperature range?
Psychrophiles are bacteria that thrive at what temperature range?
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What is the primary structure of the cell envelope that acts as a barrier to the external environment?
What is the primary structure of the cell envelope that acts as a barrier to the external environment?
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Which of the following is NOT an environmental factor influencing bacterial growth?
Which of the following is NOT an environmental factor influencing bacterial growth?
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Which of the following types of bacteria utilize light as their energy source?
Which of the following types of bacteria utilize light as their energy source?
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In the classification of bacteria, which group does not rely on organic compounds for their carbon source?
In the classification of bacteria, which group does not rely on organic compounds for their carbon source?
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Flashcards
Cell Envelope Structures
Cell Envelope Structures
Components include the plasma membrane, cell wall, and motility organelles like cilia and flagella.
Gram Stain
Gram Stain
A common staining technique to differentiate bacterial species into two groups: gram-positive and gram-negative.
Nutritional Requirements for Growth
Nutritional Requirements for Growth
Bacteria need carbon, nitrogen, ATP, phosphate, and minerals to grow.
Types of Growth Media
Types of Growth Media
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Psychrophiles
Psychrophiles
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Mesophiles
Mesophiles
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Selective Media
Selective Media
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Environmental Factors Influencing Growth
Environmental Factors Influencing Growth
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Diagnostic Microbiology
Diagnostic Microbiology
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Prokaryotes
Prokaryotes
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Eukaryotic Parasites
Eukaryotic Parasites
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Protozoa
Protozoa
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Fungi
Fungi
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Obligate aerobes
Obligate aerobes
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Generation Time
Generation Time
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Direct Plate Count
Direct Plate Count
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Fermentation
Fermentation
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Krebs Cycle
Krebs Cycle
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Lactose Fermentation
Lactose Fermentation
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Transduction
Transduction
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Extrachromosomal Elements
Extrachromosomal Elements
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Study Notes
Bacterial Cell Structure, Physiology, Metabolism, and Genetics - Chapter 1
- Microbiologists isolate, identify, and analyze bacteria to understand human diseases
- Knowledge of microbial structure and physiology is critical to clinical microbiologists in:
- Culturing organisms from patient samples
- Classifying and identifying isolated organisms
- Predicting and interpreting antimicrobial susceptibility patterns
Overview of the Microbial World
- Anton van Leeuwenhoek, a Dutch biologist/lens maker, discovered microorganisms using a homemade microscope.
- He is considered the "Father of protozoology and bacteriology" for his pioneering work.
- He observed "beasties" in water droplets
Microbes
- Microbes include bacteria, parasites, fungi, and viruses. (Images of each type are shown)
Bacteria
- Bacteria are single-celled organisms lacking a membrane-bound nucleus.
- They are categorized as prokaryotes, meaning they lack mitochondria, endoplasmic reticulum (ER), and Golgi bodies.
- These structural differences distinguish them from eukaryotes.
- Refer to Table 1-1 and Figure 1-1 for additional details (These are not included in the provided text.)
Prokaryotic Cell vs. Eukaryotic Cell
- Diagrams showcasing the distinct structures of prokaryotic and eukaryotic cells are included, highlighting differences.
Parasites
- Eukaryotic parasites can be unicellular (microscopic) or multicellular (e.g., tapeworms, which can be up to 7-10 meters long).
- Protozoa are unicellular protists that ingest food.
- Parasites can be classified based on their movement mechanisms: flagella (whip-like), pseudopodia (false feet), and cilia (eyelashes).
- Examples of parasitic organisms and their associated locomotive structures are shown.
Fungi
- Fungi are heterotrophic eukaryotes, obtaining nutrients via absorption.
- Yeasts are unicellular fungi that reproduce asexually.
- "True" yeasts do not create hyphae or mycelia.
- Most fungi are multicellular, able to reproduce both sexually and asexually.
- Multicellular fungi are composed of filaments called hyphae, which intertwine to create a mat called mycelium.
- Molds are filamentous, reproducing both ways.
- Some fungi assume both a yeast and hyphae/mycelial form, dependent on temperature.
- Yeast form at incubator/human temperature
- Filamentous form at room temperature
- Dimorphic fungi are capable of causing systemic diseases.
Viruses
- Viruses (virions) are microscopic infectious particles.
- They are not considered living organisms because they lack a cellular structure and cannot replicate independently.
- They require host cells to reproduce and metabolize.
- They cannot be visualized using ordinary light microscopes.
- Effects from viral infections can include changes in cell morphology (rounding up), the formation of viral inclusions within host cells, and the fusion of multiple cells to produce a syncytium (multinucleated infected forms).
- Viruses contain either DNA or RNA, but not both.
- They are acellular and have a protein coat, lacking cytoplasmic membranes
Classification/Taxonomy
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Taxonomy is the method of organizing and classifying organisms.
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The process uses the similarities and differences in phenotype (observable traits) and genotype (genetic makeup).
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It incorporates three categories:
- Classification and taxonomy
- Nomenclature
- Identification
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Formal levels of bacterial classification (i.e. Domain, Kingdom, Division(Phylum), Class, Order, Family, Tribe, Genus, Species)
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The hierarchical naming structure for bacteria places genera (plural of genus) in the capitalized first-order, followed by species (lower case). Both are italicized or underlined (example: Staphylococcus aureus).
- Family (e.g., Micrococcaceae)
- Genus (e.g., Staphylococcus)
- Species (e.g., aureus)
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Species can be subdivided into subspecies, serovars, and biovars, based on phenotypic characteristics.
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Phage typing is a method utilizing bacterial susceptibility to specific bacteria phages.
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Classifying organisms based on cell organization (Prokaryotic, Eukaryotic, and Archaebacteria).
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Three domains (Bacteria, Archaea, Eukarya).
Prokaryotic Cell Structure
- Describes the components of a prokaryotic cell's cytoplasmic structures, cell envelope structures, and surface polymers.
- List of structures; Circular chromosome, Mesosome, Ribosomes, Cytoplasmic granules, Endospores, Plasma Membrane, Cell Wall (Gram positive, Gram negative, Acid-fast.), Capsule, Slime Layers, Flagella, Pili, Fimbriae
Eukaryotic Cell Structure
- Describes the components of a eukaryotic cell.
- List of structures; Nucleus, Nucleolus, Nuclear membrane, Endoplasmic reticulum (ER), Golgi apparatus, Ribosomes, Mitochondria, Lysosomes, Peroxisomes, Chloroplasts, Microfilaments, Microtubules, Centrioles, Lysosomes, and Peroxisomes
Bacterial Morphology – Microscopic Shapes
- Shapes and arrangements of bacteria are described (e.g., coccus, bacillus, curved forms like spirillum/spirochete.).
Common Bacterial Stains
- Various staining techniques used to observe and identify bacterial organisms under a microscope are listed.
Microbial Growth and Nutrition
- Key nutritional needs for bacterial growth are: Carbon, Nitrogen, ATP (including phosphate, phospholipids, and sulfur), and mineral ions (Na+, K+, Cl-, Ca2+).
- Two basic groups of bacteria: autotrophs (lithotrophs), phototrophs, chemolithotrophs, and heterotrophs
- Various growth media (minimal media, nutrient media, enriched media, selective media, and differential media) are discussed.
- Specific examples of nutrient broths (Tryptic Soy Broth, Nutrient Broth).
- Different types of agar plates (blood agar, chocolate agar, MacConkey agar, colistin-nalidixic acid agar) and their uses are described.
- Transport media
- Environmental factors that influence bacteria growth; pH (neutral pH), temperature (psychrophiles, mesophiles, thermophiles ), gaseous composition
Bacterial Growth
- Generation and doubling time are discussed.
- The phases in the bacterial growth curve (lag phase, log phase, stationary phase, death phase) are described.
- Methods for determining cell numbers (direct microscopic count, direct plate count, and density measurement.) are stated
- Diagnostic schemes that analyze properties, including carbon source utilization, end products from various substrates, and pH changes in a medium.
Fermentation and Respiration
- Classifications of fermentation based on electron acceptors (anaerobic, aerobic).
- Metabolic pathways; glycolytic pathway (Embden-Meyerhof-Parnas = EMP), pentose phosphate pathway, and Entner-Doudoroff pathway- are identified.
Carbohydrate Utilization and Lactose Fermentation
- The catabolism of lactose is broken into two steps.
- The breakdown of lactose to release glucose is detailed using the enzymes β-galactosidase and β-galactosidase permease.
Bacterial Genetics
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Principles of bacterial genetics, including genotype, phenotype, and protein synthesis (replication, transcription, translation, and the function of codons).
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Genetic elements and alterations; bacterial genomes, extrachromosomal elements (i.e. plasmids), mobile genetic elements and mutations.
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Mechanisms of gene transfer: transformation, transduction, and conjugation.
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Processes of each mechanism are described in illustrations.
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Description
Explore the foundational concepts of bacterial cell structure, physiology, metabolism, and genetics in this quiz. Understanding these aspects is crucial for microbiologists in clinical settings, helping them to isolate, identify, and analyze bacteria effectively. Dive into the microbial world and learn about the significance of these organisms in human health.
