Questions and Answers
What is microbiology?
The study of microorganisms.
Microorganisms include ___ and ___ organisms.
single cells, cell clusters
Which of the following terms refer to microorganisms in relation to their role in disease?
What are the major divisions of microorganisms?
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Name one field of microbiology.
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Which of the following are types of primary producers?
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Serology is the study of viruses.
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Aerobes can extract energy from compounds only in the absence of oxygen.
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What is bioremediation?
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What is the term for organisms that grow best in extremely hot environments?
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Who introduced the germ theory of disease?
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Match the following groups with their characteristics:
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___ were the first microbes on Earth.
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What is the process called that involves introducing a tiny sample into a container of nutrient medium?
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The __________ can only survive in extremely acidic environments (pH 2-5).
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What is Koch's Postulates?
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What does DNA in prokaryotic cells look like?
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Match the following fields of microbiology with their scope:
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Which organism is known for having a chitin cell wall?
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Microbes can be beneficial to humans.
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Viruses are considered eukaryotic organisms.
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What is the importance of photosynthetic microbes?
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What classification system did Carl Linnaeus introduce?
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What do we call infectious agents that consist only of proteins?
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Study Notes
Microbiology Overview
- Derived from Greek: Mikros meaning small and logos meaning study; focuses on microorganisms.
- Specializes in microorganisms, typically requiring magnification to be seen.
- Microorganisms - include a wide variety of microscopic organisms such as bacteria, archaea, fungi, and viruses.
Major Divisions
- Prokaryotes: Bacteria and Archaea.
- Eukaryotes: Algae, Fungi, and Protozoa.
Three Domains of Life
- Domain Eukarya
- Domain Bacteria
- Domain Archaea
Major Groups of Microorganisms
- Bacteria, Fungi, Algae, Protozoa, Viruses, and Helminths (parasitic worms).
Fields of Microbiology
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Basic Research Fields:
- Bacteriology: Study of bacteria.
- Phycology: Study of algae.
- Mycology: Study of fungi and yeast.
- Protozoology: Study of protozoans.
- Parasitology: Focuses on parasitic protozoa.
- Virology: Study of viruses.
- Cytology: Structure and function of cells.
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Applied Microbiology:
- Medical Microbiology: Includes serology and immunology for disease diagnosis and treatment.
- Environmental Microbiology: Includes bioremediation and agricultural use of microbes.
Importance of Microorganisms
- Essential for nutrient production, energy flow, and recycling in ecosystems.
- Involved in bioremediation and biotechnology applications to address environmental and medical issues.
- Photosynthetic microbes produce over 50% of Earth's oxygen.
Decomposition and Nitrogen Fixation
- Microbes break down organic matter, recycling nutrients.
- Certain bacteria convert atmospheric nitrogen into forms useful for plants.
Microbial Contributions in Medicine
- Antibiotics and drugs are often derived from microbes.
- Probiotics enhance gut health and immune function.
Historical Foundations
- Antoni van Leeuwenhoek: Created the first powerful microscope and observed microorganisms.
- Spontaneous Generation: The theory that life arises from non-living matter; countered by the concept of biogenesis.
- Louis Pasteur: Established germ theory, developed pasteurization, and created vaccines.
- Robert Koch: Developed Koch's Postulates, linking specific microbes to specific diseases.
Microorganism Classification
- Taxonomy: Classification, nomenclature, and identification of organisms.
- Levels of classification include Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.
- Linnaean System: Binomial nomenclature assigns two names (genus and species) to organisms; first use is italicized.
Phylogenetic Relationships
- Classification systems evolved from the traditional five-kingdom system to Woese-Fox's three-domain system, emphasizing genetic relationships via ribosomal RNA sequences.
Physiological Diversity
- Heterotrophs: Use organic compounds for nutrients; include decomposers.
- Autotrophs: Use inorganic sources of carbon (e.g., CO2).
- Chemotrophs: Obtain energy from chemical compounds; Phototrophs utilize light energy.
- Organisms can be classified as aerobes (require oxygen) or anaerobes (do not require oxygen).
- Extremophiles: Thrive in extreme environments, pushing the limits of microbial life.
Microbial Dimensions
- Measurements:
- Micron (μ): 1 millionth of a meter.
- Nanometer (n): 1 billionth of a meter.
- Bacteria are generally several micrometers in diameter; viruses measure around 10 nm.
Public Health Considerations
- Emphasis on the role of microorganisms in diseases and their impact on human health, vaccine development, and management of infectious diseases.### Microbial Environments
- Capnophiles: Thrive in CO₂-rich environments (5-10% CO₂).
- Microaerophiles: Prefer low oxygen levels (approximately 5% oxygen).
- Acidophiles: Prefer very acidic conditions (pH 2-5).
- Alkaliphiles: Adapted to extremely alkaline environments (pH > 8.5).
- Thermophiles/Sternothermophiles: Survive in high-temperature conditions.
- Psychrophiles/Cryophiles: Grow in very cold temperatures.
- Piezophiles/Barophiles: Thrive under extreme pressure.
- Halophiles: Thrive in highly salted environments.
- Haloduric: Can survive in salty environments but do not prefer them (e.g., Staphylococcus aureus).
- Radiophiles: Resistant to harmful radiation.
- Xerophiles: Adapted to survive in extremely dry conditions.
Methods for Studying Microorganisms
- Specimen Collection: Sources can include body fluids, tissues, food, water, and soil. Collection methods utilize swabs, syringes, or transport systems that maintain microbe viability.
The Five "I"s of Microbial Processing
- Inoculation: Introducing a sample (inoculum) into a sterile nutrient medium to promote microbial growth. Certain microbes may require living hosts as growth media.
- Incubation: Culturing under controlled conditions to enhance microbial multiplication. This process may take hours to weeks, resulting in visible cultures.
- Isolation: Separating a single microbial species from others through techniques such as streaking or turbidity. Pure culture can be achieved through subculturing.
- Inspection: Observing macroscopic features (color, texture) and microscopic details (cell shape, size, motility) through staining techniques.
- Identification: Utilizing inspection data and specific tests (biochemical, immunologic, genetic) to classify and differentiate microbes.
Cell Types
- Prokaryotic Cells: Small (<5 μm), always unicellular, lack nucleus and membrane-bound organelles, circular DNA, smaller ribosomes (70S), no cytoskeleton, reproduce via binary fission.
- Eukaryotic Cells: Larger, often multicellular, possess a nucleus and organelles, linear DNA, larger ribosomes (80S), contain a cytoskeleton, reproduce via mitosis or meiosis.
Taxonomy of Organisms
- Bacteria: Prokaryotic, peptidoglycan cell walls, reproduce by binary fission (e.g., Escherichia coli).
- Archaea: Prokaryotic, lack peptidoglycan, extremophiles (methanogens, extreme halophiles, extreme thermophiles).
- Fungi: Eukaryotic, chitin cell walls, multicellular molds/mushrooms, unicellular yeasts.
- Protozoa: Eukaryotic, mainly saprobes and commensals, motility via pseudopodia, cilia, or flagella.
- Algae: Eukaryotic, cellulose cell walls, photosynthetic, produce oxygen and organic compounds, important in food chains.
- Helminths: Eukaryotic, multicellular animals, parasitic flatworms and roundworms, have microscopic life stages.
- Viruses: Acellular, obligate intracellular parasites, composed of a genome (DNA or RNA), surrounded by a protein coat (capsid), sometimes encased in a lipid envelope.
- Prions: Infectious proteins causing diseases like BSE and CJD, classified as emerging infectious diseases (EIDs).
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Description
This quiz explores the fundamental concepts of microbiology, including the study of microorganisms and their importance in public health. Learn about the role of microbes in infections and diseases and enhance your understanding of this specialized area of biology.
