Microbiology Study Guide Test 1
Microbiology Study Guide Test 1 biol 3132
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Popular in Microbiology
This 20 page Study Guide was uploaded by dcreyes3 Notetaker on Wednesday September 21, 2016. The Study Guide belongs to biol 3132 at University of Houston taught by Dr, Knapp in Fall 2016. Since its upload, it has received 6 views. For similar materials see Microbiology in Microbiology at University of Houston.
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Date Created: 09/21/16
Microbiology Study Guide Chapter 1: The Microbial World Defining what a microbe is: What are they? A microorganism, especially a bacterium causing disease or fermentation. They are minute living things that individually are usually too small to be seen with the unaided eye. How are they defined? Fungi (yeasts and molds), protozoa, and microscopic algae. It also includes viruses. (Viruses: Those noncellular entities sometimes regarded as straddling the border between life and nonlife. What are generally not considered microbes? Cells of the body. Where are they found? Microbes are found everywhere but, a long time ago before the microscope was invented microbes were unknown to scientist. Where did they come from? Who discovered them? In 1665 Robert Hooke reported that life’s smallest structural unit were “little boxes” or “cells” using his improved microscope, Hooke later saw individual cells. Robert Hooke and Antoni van Leeuwenhoek in the period of 1673-1723. Hooke presented the first published depiction of a microorganism, the microfungus Mucor. Later, Leeuwenhoek observed and described microscopic protozoa and bacteria. Origins: When did microbes arise? Spontaneously from nonliving matter; they called this hypothetical process spontaneous generation ( The idea that life could arise spontaneously from nonliving matter) Who came first? Cell theory What was the progression of cell types as life evolved? Taxonomic grouping: Microbes in Domains Bacteria and Archaea (both are prokaryotes) Domain Eukarya- Fungi, Algae, protozoans; Classifying microbes- Kingdom system: from 2 to 3 to 4 to 5 to 6 kingdoms, now all in 3 domains. 1. Kingdom Protista (once contained all microbes) prokaryotes removed from Protista and become kingdom Monera (all prokaryotes); Protista retains eukaryotic microbes only. 2. Domains: based on comparison of 165 ribosomal RNA genes 3 domains (Eukaryote, and two prokaryote domains Archaea and Bacteria. Features of: Bacteria and archaea; fungi (mold and yeast); protists ) protozoa and algae) Similarities and differences of Eukaryotic and Prokaryotic cells: Eukaryotes: Nucleus, Organelles, Linear DNA, Can be single- celled or multi-celled, such as you, me, plants, fungi, and insects. Prokaryotes: Nucleoid, Circular DNA BOTH: Cells, Cell membrane, Ribosomes Bacteria: are relatively simple, single-celled (unicellular) organisms. Their genetic material is not enclosed in a special nuclear membrane. In which, bacteria is a prokaryote. They appear in several shapes like Bacillus (rodlike), Coccus (spherical or ovoid), and Spriral (Corkscrew or curved) those are the most common shapes, but some bacteria are star- shaped or square. Individual bacteria may form pairs, chains, clusters, or other groupings. Many bacteria can “swim” by using moving appendages called FLAGELLA. Archaea: consist of prokaryotic cells, but if they have cell walls the walls will lack peptidoglycan. They are often found in extreme environments, they are divided into three main groups. Methanogens: they produce methane as a waste product from respiration. Extreme halophiles: live in extreme salty environments. Extreme thermophiles: live in hot sulfurous water. Archaea are not known to cause disease in humans. Fungi: are eukaryotes, organisms who cells have a distinct nucleus containing the cell’s genetic material (DNA) surrounded by a special envelope called the nuclear membrane. They may be unicellular or multicellular. Unlike most plants, fungi CANNOT carry out photosynthesis. True fungi have cell walls composed of a substance called CHITIN. The unicellular form of fungi, yeast, are oval microorganisms that are larger than bacteria. The most typical fungi are MOLDS. Molds form visible masses are called Mycelia, which are composed of long filaments (hyphae) that branch and intertwine. They can form on bread and fruit. Fungi can reproduce sexually and asexually. Organisms called slime molds have characteristics of both fungi and amebae. Protozoa: are unicellular eukaryotic microbes. They move by pseudopods, flagella or cilia. Amebae, they move by using extensions of their cytoplasm called pseudopods (false feet). Other protozoa have long flagella or numerous shorter appendages for locomotion called cilia. They have various shapes and they can either live in free entities or as a parasite that absorb or ingest organic compounds from their environment. Some protozoa such as Euglena are photosynthetic (They use light as a source of energy and carbon dioxide as their chief of source of carbon to produce sugars.) They reproduce sexually or asexually. Algae: are photosynthetic eukaryotes with a wide variety of shapes and both sexual and asexual reproductive forms. They are usually unicellular. The cell walls of many are composed of carbohydrates called Cellulose. They need light, water, and carbon dioxide for food production and growth, but they generally require organic compounds from environment. Viruses: They are so small they can only be seen in an electron microscope. They are acellular (not consisting of, divided into, or containing cells) They contain a core made of only one type of nucleic acid, either DNA or RNA. They can reproduce, they are considered to be living only when they multiply within host cells they infect. IMACT OF MICROBIOLOGY ON OUR LIVES Ecology: The study of the relationship between microorganisms and their environment. It includes the study of how microbial ecology has branched out and includes the study of microbial populations interact with plants and animals in various environments. Public health: Biotechnology: has undergone a revolution through the adcent of recombinant DNA technology to expand the potential of bacteria, viruses, and yeast and other fungi as miniature biochemical factories. Knowledge of cell biology Genetics: Benefits of microbes: Advances in biotechnology, agriculture (pest control), energy/environment (bioremediation), and water treatment: Bacillus thuringiensis has been used extensively in the US to control such pests as alfalfa caterpillars, bollworms, corn borers, cabbageworms, tobacco budworms, and fruit tree leaf rollers. By using microbial rather than chemical insect control, farmers can avoid harming the environment. d. Historical perspective of microbiology I. Microscopy: Hooke, microscope was capable of showing large cells, it lacked the resolution that have allowed him to see microbes clearly. Antonie can Leeuwenhoek was the first to observe live microorganisms through the magnifying lenses of the more than 400 microscopes he constructed. II. Spontaneous generation: The idea that life could arise spontaneously from nonliving matter. (Until the second half of the nineteenth century, many scientist and philosophers believed that some forms of life could arise spontaneously from nonliving matter.) III. Pasteur’s contributions disproved spontaneous generation; germ theory of fermentation. Effective treatment for many diseases were discovered by trial and error, but the causes of the diseases were unknown. The realization that yeast plays a crucial role in fermentation was the first link between the activity of a microorganism and physical and chemical change in organic materials. This discovered alerted scientist to the possibility that microorganisms might have similar relationships with plants and animals- specifically, the microorganisms might cause disease. IV. John Tyndall: Spores V. Robert Koch’s contributions: pure culture techniques, Koch’s postulates; Germ Theory of Disease. Pure Culture: is a population of cells or multicellular organisms growing in the absence of other species or types. It may originate from a single cell or single organism, in which case the cells are genetic clones of one another. He took sample of blood from a sick animal and injected it into a healthy one. The second animal developed the same disease and died, he tried it several times and there was the same result. VI. Immunization and Vaccination’ concept of immunity VII. Chemical and Physical agents of control: Chemical agents are used to control the growth of microbes on both living tissues and inanimate objects. Physical agents of control are preserve foods. Dying (desiccation) and salting (osmotic pressure) Antiseptics/disinfectants how do they differ: Antiseptics agent that kills or inhibits the growth of microorganisms on the external surfaces of the body. They should generally be distinguished from drugs such as antibiotics that destroy microorganisms internally and fro disinfectants, which destroy microorganisms found on nonliving objects. Synthetic drugs: Paul Ehrilich who fired the first shot in the chemotherapy revolution. He speculated about a “magic bullet” that could hunt down and destroy a pathogen without harming the host. In 1910, after testing hundreds of substance he found a chemotherapeutic agent called salvarsan, an arsenic derivative effective against syphilis. By the late 1930’s, researchers had developed several synthetic drugs that could destroy microorganisms. Discovery of antibiotics:The first antibiotic was discovered by accident. Penicillium Chysogenum. Alexander Fleming, he noticed a curious pattern of growth on a plate of mold in which, a clear area where bacterial growth had been inhibited encircled by mold. Now Penicillin is an antibiotic produced by fungus. VIII. Microbial ecology: Winogradsky/Beijerinck and enrichment culture; importance of microbes in geochemical cycling; autotrophs/heterotrophs/lithotrophs; nitrogen cycle; decomposition: Winogradsky and Beijerinck They were the first to show how bacteria help recycle vital elements between the soil and the atmosphere. Autotrophs: (self- feeders) use carbon dioxide. Are also referred to as lithotrophs (rock eating) Heterotrophs: (feeder on others) requires an organic carbon source. They are also referred to as organotrophs. Nitrogen cycle: All organisms need nitrogen to synthesized protein , nucleic acids, and other nitrogen-containing compounds. Nitrogen, in the atmosphere goes through fixation, nitrification and denitrification. Nitrates assimilated into plants and animals after nitrification go through decomposition, ammonification, and then nitrification again. Decomposition: Results in the hydrolytic breakdown of proteins into amino acids. (Ammonification, Nitrogen Cycle) During, the organic compounds are oxidized, and CO2 is returned to the cycle. (Carbon Cycle) E. Microbes and Diseases: i. Microbiota; symbioses commensalism/mutation; opportunistic pathogen. ii. Infectiousdisease pathogen host defenses and pathogenesis; viulence/virulence factors; EID’s: Methods for studying Microorganisms (part of CH 3 and 6) Culturing microorganisms Five I’s: Inoculation: The introduction of a sample into a container of media to produce a culture of observable growth, Isolation: separating one species from another, Incubation: putting a culture under conditions that allow growth, Inspection: , Identification. Inoculation and Incubation; Sources: 1. Source of microbes for incubation: You can find them everywhere 2. Growth medium to inoculate: Bacterial growth curve… The lag phase, The Log phase, The Stationary phase, and The Death phase. a) Form of medium (solid, liquid, semi-solid) and use of each: Solid: a solidifying agent such as agar is added to the medium. A complex polysaccharide derived from a marine alga, agar has long been used as a thickener in foods such as jellies and ice cream. Liquid: is called Nutrient broth, when agar is added, it is called nutrient agar. (Agar itself is not a nutrient) The medium (enrichment medium) for an enrichment culture is usually liquid and provides nutrients and environmental conditions that favor the growth of a particular microbe but not others. b) Chemical composition: Defined v. complex: Defined Media: is one whose exact chemical composition known. Complex Media: A culture medium in which the exact chemical composition is not known. c) Functional type: general purpose; enriched anaerobic growth; specimen transport; assay; selective; differential. Isolation: Colony formation on solid media; pure culture States of culture: pure/mixed/contaminated how do these differ? Inspection and Identification: Microscopy: cellular morphology a) Effective microscopy: magnification; resolution (wavelength of light; oil immersion); contrast (light and staining) b) Staining: preparation (live cells or fixed smear; acidic and basic dyes; differential staining and special staining and special staining (enhance specific structures, flagella, capsules) Colony morphology Biochemical Tests: is frequently used to identify bacteria and yeasts because different species produce different enzymes. They can be designed to detect the presence of enzymes. One type of biochemical test detects amino acid catabolizing enzymes involved in decarboxylation and dehydrogenation. Genetic testing: Can now be used to screen for several hundred genetic disease. This screening can be performed on prospective parents and also on fetal tissue. Genetic testing can help a physician prescribe the correct medication for a patient. Immunological testing Chapter 4 (functional Anatomy of Prokaryotes a) Features of all cell types; Prokaryotic v. Eukaryotic cells: Prokaryotes: Typically their DNA is not enclosed within a membrane and is usually a singular, circularly arranged chromosome. Their DNA is not associated with histones (special chromosomal proteins found in eukaryotes) other proteins are associated with the DNA. They generally lack organelle. Their cell walls almost always contain the complex polysaccharide peptidoglycan They usually divide by binary fission, where DNA is copied, and the cell splits into two cells. This involves fewer structures and processes than eukaryotic cell division. Eukaryotes: The DNA is found in the cell’s nucleus, which is separated from the cytoplasm by a nuclear membrane, and the DNA is found in multiple chromosomes. Their DNA is consistently associated with chromosomal proteins called histones and with nonhistones. They have a number of membrane-enclosed organelles, including: Mitochondria, Endoplasmic Reticulum, Golgi Complex, Lysosomes, and sometimes Chloroplasts. Their cell walls, when presented are chemically simple. Cell division usually involves mitosis. b) The Prokaryotic cell morphology: Morphology (shape) Coccus, are usually round but can be oval, elongated or flattened on one side. Cocci (plural) Bacillus ( rod-shaped) Spiral c) Prokaryotic cell structure External: glycocalyx- capsule, slime layer; biofilms; flagella (structure/ mode of action/ chemotaxis/ H antigen); axial filaments; fimbriae/ pili d) Bacterial cell wall structure- know/ understanding these: i. Peptidoglycan layer: Structure (NAG-NAM + peptide cross bridges); action of penicillin ii. Gram positive cell wall: external to plasma membrane; thick, contains teichoic acids. In most, the cell wall consists of many layers of peptidoglycan, forming a thick, rigid structure. iii. Gram negative cell wall: thin peptidoglycan between plasma membrane and an outer membrane; is the periplasmic space. Cell walls contain only a thin layer of peptidoglycan. It consist of one or a very few layers of peptidoglycan and an outer membrane. The peptidoglycan is bonded to lipoproteins in the outer membrane and is in the periplasm, a gel-like fluid in the periplasmic space of gram negative bacteria, the region between the outer membrane and the plasma membrane. 1) Murein lipoprotein: is a critical outer membrane component involved in Salmonella enterica serovar typhimurium systemic infection. 2) Outer membrane: LPS layer structure; O polysaccharides (O antigen), Lipid A, core polysaccharide iv. Mycobacterium cell wall; acid-fast- contain waxy mycolic acids external to the peptidoglycan cell wall v. Archaea: contain pseudomurein (not peptidoglycan) vi. Mycoplasma: lack cell wall e. Plasma membrane: Phospholipids, proteins, functions. Eukaryotic membranes also contain carbohydrates, which serve as attachment sites for bacteria and as receptor sites that assume a role in such functions as cell-cell recognition. Eaukaryotic plasma membrane also contain sterols, complex lipids not found in prokaryotic plasma membrane. i. Transport mechanisms: passive (simple and facilitated diffusion), active transport; osmosis (hyper-/hypo-/iso-tonic) f. Cytoplasm (solutes and structures); Nucleoids region: nature and organization of bacterial chromosome; plasmids; ribosomes (30S. 50S) polysome formation g. Specialized structures: i. In phototrophs- thylakoids; corboxysome ii. Inclusions- various type storage granules (metachromatic granules, glycogen, starch, PHB (lipid); magnetosome; gas vacuoles, sulfur granules. iii. Endospores: very resistantl sporulation process (spectrum & coat formation); dipicolinic acid, spore location; germination. Genera Clostridium and Bacillus are endospore formers. h. Eukaryotic cells; compare to prokaryotic cells i. Endosymbiont theory what is it? Evidence for it. (Symbiogenesis) Chapter 12 (Fungi, Algae. Protozoa, Helminths) a) Fungi: i. Are chemoheterotrophs; absorb nutrients, decomposition; aerobic or facultative anaerobic; both sexual and asexual reproduction ii. Compared to bacteria, fungi grow in more acidic environments; are more resistant to osmotic pressure; and can grow with very low moisture content. iii. Molds and fleshy fungi: filamentous; vegetative and aerial hyphae; mycelium; produce spores for reproduction. iv. Yeast: unicellular; reproduce by budding/fission v. Dimorphic fungi vi. Pathogens; fungal diseases mycoses (systemic/cutaneous/subcutaneous) b) Algae i. Photosynthetic; unicellular (dinoflagellates/diatoms) & multicellular forms (red/brown/some green algae) ii. Algal diseases due to toxins produced by certain algae; are not infectious c) Protozoans i. Unicellular, mostly aerobic, heterotrophs ii. Diverse features: 1) Motility ciliated types; amoeboid ( pseudopodia); flagellated; undulating membrane 2) Cyst formation; may have complex life cycles with different stages and hosts (Apicomplexa- Malaria) 3) Nutritional adaptations 4) Reproduction: Sexual and Asexual (fission/budding/schizogony) d) Helminths: parasitic worms ( flatworms and roundworms) i. Multicellular eukaryotic animals; specialized to live in hosts ii. Platyhelminthes (hermaphroditic): 1) Trematodes: Flat; absorb food through cuticle; named for host tissue 2) Cestodes: Tapeworms; scolex attaches to tissue; absorbs food body surface; proglottid segments of body 3) Pathogens: Schistozoma; Taenia iii. Nematodes: complete digestive system; male/female sexes; free-living and parasitic types; eggs or larvae can be infective, depending on type. Ascaris; Trichenollosis; heartworm. Chapter 13, Part 1 (Viruses, Viroids, and Prions) a. Viruses: Discovery and characterization; viral size. Define: acellular and obligate intracellular parasites; virions. b. Features of Viruses i. Viral infectivity: What does this depend on? Virion; host range and tissue specificity 1) Basic viral infection: recognize host and attach (how and in what way) get viral genome inside host cell make copies of viral genome transcribe/translate viral genome to make viral proteins assemble viral particles exit host. ii. Viral structure: 1) Genome: The haploid set of chromosomes in a gamete or microorganism, or in each cell of a multicellular organism. 2) Capsid- capsomere: Is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. 3) Glycoprotein spikes: The substance that makes up the spikes that are projections found on the envelopes of certain enveloped viruses. (SPIKES)- Projections on the envelope of certain enveloped viruses. Certain spiked viruses cause RBC’s to clump. Useful in virus identification. 4) Enveloped viruses- origin of envelope? “Naked” viruses what are these? Viruses that have a bilayer membrane outside their capsids. Viruses that have no bilayer membrane are “naked” ( A virus with only a nucleocapsid but no envelope, or non-enveloped viruses. 5) Complex viruses: Viruses with more elaborate coats or capsids. 6) Viral genomes: Can direct biosynthesis inside a host cell, and some viral genomes can be incorporated into the host genome. b) Taxonomy; viral species: is classify living organisms- that is, to establish the relationship between one group of organisms and another and to differentiate them. They also provides a common reference for identifying organisms already.
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