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Questions and Answers
What is the primary purpose of antisepsis?
What is the primary purpose of antisepsis?
Which method is classified under physical methods of disinfection?
Which method is classified under physical methods of disinfection?
Which of the following is NOT a method of sterilization?
Which of the following is NOT a method of sterilization?
What occurs during the elongation phase of DNA replication in prokaryotes?
What occurs during the elongation phase of DNA replication in prokaryotes?
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Which of the following substances is commonly used as a disinfectant?
Which of the following substances is commonly used as a disinfectant?
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In eukaryotic DNA replication, what is the role of telomeres?
In eukaryotic DNA replication, what is the role of telomeres?
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What is the main function of ligase during the termination phase of DNA replication?
What is the main function of ligase during the termination phase of DNA replication?
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Which technique is not effective for microbial control at low temperatures?
Which technique is not effective for microbial control at low temperatures?
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What technique did Edward Jenner pioneer for immunization?
What technique did Edward Jenner pioneer for immunization?
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Which type of microscope is specifically used to visualize the internal structure of specimens at high resolution?
Which type of microscope is specifically used to visualize the internal structure of specimens at high resolution?
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What is the primary function of a simple stain in microscopy?
What is the primary function of a simple stain in microscopy?
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What characteristic differentiates Gram-positive bacteria from Gram-negative bacteria?
What characteristic differentiates Gram-positive bacteria from Gram-negative bacteria?
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Which organelle is not typically found in prokaryotic cells?
Which organelle is not typically found in prokaryotic cells?
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What process allows bacteria to move nutrients across their membrane without using energy?
What process allows bacteria to move nutrients across their membrane without using energy?
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What structure is formed by some bacteria under stress to ensure survival in adverse conditions?
What structure is formed by some bacteria under stress to ensure survival in adverse conditions?
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Which of the following is a feature of eukaryotic cells that distinguishes them from prokaryotic cells?
Which of the following is a feature of eukaryotic cells that distinguishes them from prokaryotic cells?
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What is the primary mechanism by which heat sterilizes microbial agents?
What is the primary mechanism by which heat sterilizes microbial agents?
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Which method is used to sterilize tools and media at 121°C?
Which method is used to sterilize tools and media at 121°C?
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What is the effect of ionizing radiation on microbial cells?
What is the effect of ionizing radiation on microbial cells?
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In the disk diffusion method, what does a zone of inhibition indicate?
In the disk diffusion method, what does a zone of inhibition indicate?
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Which of the following statements about disinfectants is true?
Which of the following statements about disinfectants is true?
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What is the definition of Thermal Death Point (TDP)?
What is the definition of Thermal Death Point (TDP)?
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What is the primary function of filtration in microbial control?
What is the primary function of filtration in microbial control?
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Which of the following best describes the role of quaternary ammonium compounds?
Which of the following best describes the role of quaternary ammonium compounds?
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Which type of bacteria is known for being found in the human gut microbiome and plays a key role in digesting complex carbohydrates?
Which type of bacteria is known for being found in the human gut microbiome and plays a key role in digesting complex carbohydrates?
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Which of the following bacteria is primarily known as an opportunistic pathogen in patients with cystic fibrosis?
Which of the following bacteria is primarily known as an opportunistic pathogen in patients with cystic fibrosis?
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What is a defining characteristic of Epsilon-proteobacteria?
What is a defining characteristic of Epsilon-proteobacteria?
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What is the primary metabolic byproduct produced by methanogens?
What is the primary metabolic byproduct produced by methanogens?
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Which bacterium is associated with causing peptic ulcers and could be linked to gastric cancer?
Which bacterium is associated with causing peptic ulcers and could be linked to gastric cancer?
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Which of the following bacterial types is known for its role in the sulfur cycle?
Which of the following bacterial types is known for its role in the sulfur cycle?
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What type of hyphae are specialized for nutrient absorption in fungi?
What type of hyphae are specialized for nutrient absorption in fungi?
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Which is a common pathogenic species that causes Lyme disease?
Which is a common pathogenic species that causes Lyme disease?
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What is the primary role of tRNA during translation?
What is the primary role of tRNA during translation?
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Which process involves the assembly of the ribosome at the start codon?
Which process involves the assembly of the ribosome at the start codon?
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What type of mutation results from a single base change, such as substitution?
What type of mutation results from a single base change, such as substitution?
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What is the primary function of restriction enzymes in biotechnology?
What is the primary function of restriction enzymes in biotechnology?
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During PCR, what occurs at the denaturation step?
During PCR, what occurs at the denaturation step?
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Which method of gene transfer involves a bacteriophage transferring DNA?
Which method of gene transfer involves a bacteriophage transferring DNA?
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What is the role of gel electrophoresis in molecular biology?
What is the role of gel electrophoresis in molecular biology?
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In what form is the genetic information in DNA primarily structured?
In what form is the genetic information in DNA primarily structured?
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What is the pathogenesis of SARS-CoV-2 in humans?
What is the pathogenesis of SARS-CoV-2 in humans?
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Which statement correctly describes the lytic and lysogenic cycles of a virus?
Which statement correctly describes the lytic and lysogenic cycles of a virus?
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What type of vaccine is primarily used in the campaigns against COVID-19?
What type of vaccine is primarily used in the campaigns against COVID-19?
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Which of the following is an example of a vector-borne transmission method?
Which of the following is an example of a vector-borne transmission method?
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What term describes the average number of secondary infections from a single infected individual?
What term describes the average number of secondary infections from a single infected individual?
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Which of the following accurately describes the role of adhesins in pathogenicity?
Which of the following accurately describes the role of adhesins in pathogenicity?
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Which type of infection is linked to the development of antibiotic-resistant microbes in healthcare settings?
Which type of infection is linked to the development of antibiotic-resistant microbes in healthcare settings?
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What characterizes endotoxins in terms of their composition and effect?
What characterizes endotoxins in terms of their composition and effect?
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Study Notes
Microbial World and You
- Binomial Nomenclature: A naming system that gives each organism a two-part Latin name, e.g., Escherichia coli (E. coli).
- Hierarchy of Classification: Kingdom, Phylum, Class, Order, Family, Genus, Species, organizes organisms into categories.
- Taxonomy: The science that classifies organisms, provides universal names, and places them in categories.
Types of Microbes
- Bacteria: Single-celled, prokaryotic organisms with peptidoglycan cell walls. Some are motile by flagella.
- Archaea: Prokaryotic; distinct from bacteria, often found in extreme environments.
- Fungi: Eukaryotic organisms; yeasts (unicellular) and molds (multicellular) that decompose organic material.
- Protozoa: Single-celled eukaryotes, that often move by pseudopods, cilia, or flagella.
- Algae: Photosynthetic eukaryotes, vital for aquatic food chains and oxygen production.
- Viruses: Acellular, obligate intracellular parasites, made of nucleic acids (DNA or RNA) enclosed in a protein coat.
- Multicellular Animal Parasites: Helminths (worms), which affect human health.
Classification of Microbes
- Domains:
- Bacteria: Unicellular prokaryotes with peptidoglycan walls.
- Archaea: Prokaryotes lacking peptidoglycan. Often extremophiles.
- Eukarya: Includes protists, fungi, plants, and animals.
Spontaneous Generation Debate
- Proponents believed life arose from nonliving matter.
- Opponents argued for biogenesis, that life arises only from preexisting life.
Pasteur's S-neck Flask Experiment
- Demonstrated that microbes, not air, cause contamination. Contained sterile broth that remained free of microbes.
Koch's Postulates
- Establishes a causal relationship between a microbe and a specific disease:
- The pathogen must always be present in cases of the disease.
- The pathogen must be isolated and grown in a pure culture.
- The cultured pathogen must cause the disease in a healthy host.
Observing Microorganisms Through a Microscope
- Compound Light Microscope: Uses visible light; magnifies up to ~1000x.
- Phase-Contrast Microscope: Enhances contrast in transparent specimens without staining.
- Fluorescence Microscope: Uses UV light for viewing fluorescently labeled structures.
- Electron Microscope:
- Transmission Electron Microscope (TEM): High-resolution internal structures.
- Scanning Electron Microscope (SEM): 3D images of surface structures.
- Resolution and Magnification: Resolution depends on light wavelength and lens; magnification is objective lens × ocular lens.
Preparing Smears for Staining
- Specimens are spread thinly on a slide, air-dried, heat-fixed, then stained to visualize structures.
Types of Stains
- Simple Stain: Uses a single dye for visualization.
- Differential Stain: Highlights differences. Examples include Gram stain (distinguishes Gram-positive and Gram-negative bacteria).
- Special Stains: Visualize specific structures (e.g., endospore, capsule stains).
Prokaryotic and Eukaryotic Cells Functional Anatomy
- Prokaryotic Cells: Have cell walls, plasma membranes, ribosomes, nucleoid, pili, flagella, and sometimes capsules and endospores.
Microbial Metabolism
- Enzymes: Facilitate metabolic reactions. Composed of apoenzymes (protein portion) and cofactors/coenzymes (non-protein helpers).
- Factors Affecting Enzyme Activity: Temperature, pH, substrate concentration, and inhibitors (competitive and non-competitive).
- ATP Generation: Substrate-level phosphorylation and oxidative phosphorylation.
Key Pathways
- Glycolysis, Krebs Cycle, Electron Transport Chain, and Fermentation.
Microbial Growth Requirements
- Physical: Temperature, pH, osmotic pressure, and specific chemical factors (carbon, nitrogen, sulfur, trace elements).
- Types of Media: Selective media, differential media, enrichment media.
Control of Microbial Growth
- Microbial Death Rate: The permanent loss of reproductive ability in a population.
- Actions of Microbial Control Agents: Alter membrane permeability, denature proteins, or damage DNA/RNA.
- Physical Methods of Microbial Control: Heat, filtration, radiation, or desiccation.
Microbial Genetics
- DNA Replication: Prokaryotic: initiation, elongation, termination, and steps involved in eukaryotic DNA replication.
- Transcription: DNA to mRNA using RNA polymerase.
- Translation: mRNA to polypeptides using ribosomes.
Biotechnology
- Recombinant DNA (rDNA): Combining DNA from different sources to create genetic modifications.
Cloning Methods
- Restriction Enzymes : cut DNA at specific sequences. PCR : amplifies specific DNA sequences.
- Gel Electrophoresis: Separates DNA fragments by size.
- Southern Blotting: Transfers DNA from gel to membrane for detection.
- DNA Structure : Double helix, antiparallel strands, and base pairing (A-T, G-C).
- DNA Replication: Semi-conservative process involving helicase, DNA polymerase, etc.
Classification of Microorganisms
- Domains: Bacteria, Archaea, Eukarya.
- Biochemical Tests: Identify metabolic characteristics.
- Serology: Detects antigens or antibodies (e.g., ELISA, Western blotting).
- DNA Fingerprinting: Compares DNA patterns for identification.
- Cladograms: Visual representations of evolutionary relationships.
Chemotherapy
- Spectrum of activity: Broad or narrow spectrum.
- Mode of action: Inhibit cell wall synthesis, disrupt cell membranes, inhibit protein synthesis, inhibit nucleic acid synthesis, or antimetabolites.
Prokaryotes
- Proteobacteria: Largest bacterial phylum. Includes important examples like Escherichia coli, Rhizobium, Rickettsia, Burkholderia, Neisseria, and Pseudomonas.
- Other bacterial classes, like Spirochetes,Bacteroidetes, and Fungi & Protozoa.
Viruses
- Structure: Nucleic acid (DNA or RNA), protein capsid, sometimes an envelope.
- Growth: Viral multiplication requires a host cell.
- Types: Lytic cycle, and lysogenic cycle (prophage).
- SARS-CoV-2: Details about COVID-19, its effects, and pathogenesis, including how it infects cells and replicates itself.
Epidemiology
- Classifying infectious diseases: Acute, chronic, latent, communicable, non-communicable.
- Development of disease: Incubation, prodromal, illness, decline, and convalescence.
- Transmission: Direct or indirect contact, vector-borne, fomites.
- Vectors: Biological, mechanical.
- Nosocomial infections: Hospital-acquired infections.
Pathogenicity
- Adherence: Microbes attaching via adhesins (e.g., fimbriae).
- ID50: Infectious dose necessary to infect 50% of the population, related to pathogen's virulence or ability to cause disease.
- Exotoxins: Secreted proteins; trigger inflammation and have specific targets (e.g., neurotoxins, enterotoxins).
- Endotoxins: Lipid A components of the outer membrane of Gram-negative bacteria that trigger inflammation.
- Parenteral Route: Pathogens that bypass barriers (injections, wounds)
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Description
Test your knowledge on the microbial world, including the classification and naming of organisms. This quiz covers topics such as binomial nomenclature, taxonomy, and different types of microbes such as bacteria, fungi, and viruses. Challenge yourself to understand the diversity of life forms that exist around us.
