Created by Nicole Cordero
Branch of science that deals with the study of microorganisms, which are living entities that are too small to be seen with the naked eye. Microorganisms include bacteria, viruses, fungi, protozoa, and algae. Microbiology encompasses various sub-disciplines, including bacteriology (study of bacteria), virology (study of viruses), mycology (study of fungi), parasitology (study of parasites), and immunology (study of the immune system). Microbiologists study the structure, function, classification, and interactions of microorganisms, as well as their roles in health, disease, industry, and the environment. They employ various techniques such as microscopy, culturing, genetic analysis, and molecular biology methods to investigate microorganisms and their activities. Microbiology has diverse applications in fields such as medicine, agriculture, food safety, environmental science, biotechnology, and pharmaceuticals.
Power sources:
a) Phototrophic: Microorganisms that obtain energy from light through photosynthesis.
b) Chemotrophic:
Carbon sources:
a)Autotrophic:
b) Heterotrophic:
c) Methylotrophic: Microorganisms that can utilize organic compounds without carbon-carbon bonds.
a. Growth: Increase in the number of microorganisms in a population.
b. Binary fission: A method of microbial reproduction where one cell divides into two identical daughter cells.
c. Generation time: The time it takes for a population of microorganisms to double in number.
1Diplococcus: Cells arranged in pairs.
Streptococcus: Cells arranged in chains.
Staphylococcus: Cells arranged in clusters.
Micrococcus: Cells arranged in clusters resembling grapes.
Sarcina: Cells arranged in cuboidal packets.
Angle arrangement: Cells arranged at an angle to each other.
Filament: Elongated cells forming a chain-like structure.
These events have significantly shaped our understanding of microorganisms, disease causation, and the development of techniques for studying and manipulating microorganisms.
1. Cocci: Spherical-shaped cells.
2. Bacilli: Rod-shaped cells.
3. Spiral: Spiral or helical-shaped cells.
4. Pleomorphism: Variation in shape observed in some bacteria like Chlamydia and Rhizobium.
Use of moist heat:
Autoclave: High-pressure steam sterilization.
Ionizing radiation → Gamma rays: High-energy electromagnetic radiation used for sterilization.
Ultraviolet radiation: Germicidal UV light used to kill or inactivate microorganisms.
Transmission Electron Microscope (TEM): Uses electron beams to visualize thin sections of cells.
Scanning Electron Microscope (SEM): Provides detailed 3D images of the cell surface.
a. Bacterial transformation: Uptake and incorporation of foreign DNA into bacterial cells.
b. Transduction: Transfer of genetic material between bacteria by viruses (bacteriophages).
c. Conjugation: Transfer of genetic material between bacteria through direct cell-to-cell contact.
Cell number count:
Direct counting:
Indirect counting:
Population growth curve:
a. Lag phase: Period of adjustment where cells are metabolically active but not multiplying significantly.
b. Exponential phase (log phase): Rapid growth phase with exponential increase in cell numbers.
c. Stationary phase: Period of equilibrium where cell growth and death rates are balanced.
d. Decay phase (death phase): Decline in cell numbers due to depletion of nutrients or accumulation of toxic waste products.
Special techniques for growing bacteria:
a. Continuous (open) cultures:
b. Synchronized cultures: Techniques to achieve cell populations in the same growth phase by manipulating culture conditions.
1. Bright field: Illumination from below, provides contrast between cells and background.
2. Dyes: Staining techniques using acidic or basic dyes.
3. Staining:
a) Simple: Single dye used to visualize cells.
b) Differential: Multiple dyes used to differentiate different cell structures.
c) Special: Specific staining techniques for certain structures or organisms.
4. Dark field: Illumination from the sides, enhancing contrast of unstained cells.
5. Fluorescence: Staining technique using fluorescent dyes to visualize specific structures.
6. Phase contrast: Enhances contrast by exploiting differences in refractive index.
Endospore structure:
a) Exospore: Outermost layer of the endospore.
b) Cortex: Thick layer beneath the exospore.
c) Coat: Proteinaceous layer surrounding the cortex.
d) Inner membrane: Surrounds the core of the endospore.
e) Core: Contains the cell's DNA and essential structures.
Sporogenesis: The process of endospore formation.
Endospore germination: The process of an endospore reverting to a vegetative state.
Comparison of prokaryotic with eukaryotic cell: Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have a true nucleus and various membrane-bound organelles. Eukaryotic cells are generally larger and more complex than prokaryotic cells.
Roman philosopher, first observed magnification effects using water-filled glass spheres.
Dutch tradesman and scientist, perfected the single-lens microscope and made significant observations of microorganisms.
living entities that lack cells or do not possess typical cellular structures.
a) O antigen: Part of the lipopolysaccharide (LPS) found in the outer membrane of Gram-negative bacteria.
b) "Core polysaccharide": Part of the LPS structure.
c) Lipid A: The toxic component of LPS.
Cidal (killing):
b. Static (inhibiting)
c. Categories of antimicrobial agents:
d. Antimicrobial agents against fungi and protozoa: Specific agents designed to target fungal and protozoan pathogens.
e. Antiviral drugs: Drugs that specifically target and inhibit viral replication.
living organisms that consist of one or more cells. These organisms have typical cellular structures, including a cell membrane, cytoplasm, and organelles.
Branch of biomedical science that focuses on the study of the immune system and its responses to foreign substances, infectious agents, and diseases. It explores the mechanisms by which the immune system recognizes and defends against pathogens, as well as its role in maintaining homeostasis and preventing autoimmune diseases.
Dutch spectacle maker, is credited with inventing the compound microscope in the late 16th century.
Koch formulated the germ theory of disease in the late 19th century, identifying specific microorganisms as the causes of specific diseases.
They discovered restriction enzymes, which led to the development of recombinant DNA technology.
Mullis invented the polymerase chain reaction (PCR), a revolutionary technique for amplifying DNA sequences.
Nucleoid: Region where the bacterial chromosome (DNA) is located.
Plasmid: Small, extrachromosomal DNA molecules that can confer additional genetic traits.
Ribosomes: Involved in protein synthesis.
Inclusions:
a) Metachromatic granules: Phosphate storage structures in certain bacteria. b) Poly-beta hydroxybutyrate granule: Energy storage structure.
c) Gas vacuole: Buoyancy-regulating structure in certain aquatic bacteria.
branch of microbiology that focuses specifically on the study of viruses.
Koch developed a set of criteria, known as Koch's postulates, for establishing the causative relationship between a microorganism and a disease. This led to the discovery of many disease-causing microorganisms and marked the golden age of microbiology.
a) Peptidoglycan or murein: Provides structural support and determines cell shape.
b) Tetrapeptide side chain: Part of the peptidoglycan structure.
c) Teichoic acids: Found in the cell walls of some bacteria.
It encompasses all eukaryotic organisms, which are characterized by having cells with a true nucleus and membrane-bound organelles. Eukarya includes a diverse range of organisms, including plants, animals, fungi, and protists.
Redi conducted experiments in the 17th century that challenged the idea of spontaneous generation, showing that maggots on decaying meat came from eggs laid by flies.
crystallized TMV, confirming its nature as a particle and further advancing the field of virology.
Viruses are acellular microorganisms that consist of genetic material, either DNA or RNA, enclosed in a protein coat called a capsid. Some viruses may also have an outer envelope derived from the host cell membrane. Viruses cannot reproduce or carry out metabolic activities on their own and require a host cell to replicate and produce new viral particles.
Virology is a broad discipline that encompasses the study of viruses in various contexts, including human viruses, animal viruses, and plant viruses.
Prions are another type of acellular microorganism. They are misfolded proteins that can induce abnormal folding in normal proteins, leading to the formation of protein aggregates. Prions are associated with several neurodegenerative diseases in animals and humans, such as Creutzfeldt-Jakob disease and mad cow disease.
Metchnikoff discovered phagocytes, immune cells that engulf and destroy pathogens, and contributed to the understanding of innate immunity.
Capsule:
a) Chemical composition: Usually composed of polysaccharides.
b) Detection: Negative staining or the quellung reaction can be used to detect the presence of capsules.
Glycocalyx:
a) Dextran: Sticky substance produced by certain bacteria, involved in biofilm formation.
b) Dental plaque: Accumulation of bacteria and extracellular material on teeth. c) Cavities: Decay of tooth structure caused by bacteria.
Pili:
a) Pili type I: Involved in attachment to host cells.
b) Pili type F: Involved in bacterial conjugation.
Flagella:
a) Basal body: Anchors the flagellum to the cell membrane.
b) Filament: Long, whip-like structure responsible for cell movement.
c) Hook: Connects the basal body to the filament.
d) Movement: Bacteria can exhibit movement through chemotaxis, phototaxis, air taxis, or magnetotaxis.
Needham conducted experiments in the 18th century that seemed to support spontaneous generation by observing microbial growth in sealed flasks containing boiled broth.
Pasteur's experiments in the 19th century definitively disproved spontaneous generation and supported the concept of biogenesis.
The discovery of bacteriophages, viruses that infect bacteria, in the early 20th century opened new avenues for understanding microbial interactions.
Prokarya, also known as prokaryotes, is a domain of single-celled organisms that lack a nucleus and other membrane-bound organelles.
Phycology is the scientific study of algae, which are a diverse group of photosynthetic organisms within the kingdom Protista.
Protozoology is the scientific study of protozoa, which are a diverse group of single-celled eukaryotic microorganisms. Protozoa belong to the kingdom Protista and are classified based on their characteristics, such as locomotion, morphology, and mode of nutrition
Mycology is the scientific study of fungi, which are a diverse group of eukaryotic organisms within the kingdom Fungi.
Ehrlich and Von Behring developed the concepts of toxins and antibodies, leading to the development of serums and vaccines.
Viroids, which are small circular RNA molecules that can infect plants, are also acellular, but they are not considered microorganisms as they do not infect humans or animals. Viroids interfere with the normal cellular processes of plants, causing disease symptoms.
Ivanowsky discovered that a filterable infectious agent caused tobacco mosaic disease, laying the groundwork for the discovery of viruses.
was the first to isolate and characterize a virus, the tobacco mosaic virus (TMV).
Spallanzani replicated Needham's experiments and showed that boiling the broth for a longer time and sealing the flasks prevented microbial growth.
developed the first successful vaccine against smallpox, demonstrating the concept of immunization.
unicellular microorganisms that have a prokaryotic cellular structure. They have a cell membrane and a cell wall, and their genetic material is in the form of circular DNA present in the cytoplasm. Bacteria play vital roles in various ecosystems, including nutrient cycling, symbiotic relationships, and some can cause diseases.
unicellular microorganisms with a prokaryotic cellular structure. They are distinct from bacteria and often inhabit extreme environments such as hot springs, deep-sea hydrothermal vents, and acidic environments. Archaea have unique genetic and biochemical characteristics.
Algae are a diverse group of photosynthetic organisms that can be found in various aquatic and terrestrial environments. They are eukaryotic microorganisms that range from unicellular (such as diatoms and dinoflagellates) to multicellular forms (such as seaweeds). Algae play a crucial role in aquatic ecosystems as primary producers, contributing to oxygen production and serving as a food source for other organisms.
Protozoa are eukaryotic microorganisms that are typically single-celled and can be found in various habitats, including freshwater, marine environments, and soil. They exhibit diverse ecological roles and can be free-living or parasitic. Protozoa have a range of feeding mechanisms and can be classified into various groups based on their locomotion, such as amoeboid movement, cilia, or flagella.
Fungi are eukaryotic organisms that include yeasts, molds, and mushrooms. They have a distinct cellular structure with a cell wall composed of chitin. Fungi obtain nutrients through absorption from their surroundings, decomposing organic matter. Some fungi form beneficial relationships with other organisms (such as mycorrhizal associations with plant roots), while others can cause diseases in plants, animals, and humans.