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Microbiology CCGA
Lecture 5,6,7,8 Dr White CCGA
| Question | Answer |
|---|---|
| Metabolism | 1. Collection of controlled biochemical reactions that take place within an organism. 2.Ultimate function of metabolism is to reproduce the organism. (Biological Imperative) |
| Every cell acquires | Nutrients |
| Metabolism requires | Energy from Light or from Catabolism of nutrients |
| Energy is stored in | adenosine triphosphate (ATP) |
| Cells catabolize (break down) nutrients to form | Precursor Metabolites |
| Precursor metabolites, energy from ATP, and enzymes are used in anabolic reactions | make larger molecules from smaller ones |
| Enzymes plus ATP form macromolecules | larger molecules made into macromolecules |
| Cells grow | by assembling macromolecules |
| Cells reproduce | once they have doubled in size |
| Catabolic pathways | break larger molecules into smaller products (Exergonic)release energy |
| Anabolic pathways | synthesize large molecules from smaller products of catabolism (endergonic)require more energy than they release |
| catabolic reaction | broken down |
| anabolic reaction | built up |
| Many metabolic reaction involve the __________ from an electron donor to an electron receptor. | transfer of electrons |
| Many metabolic reaction involve the transfer of electrons from an electron donor to an electron receptor. | oxidation-reduction reactions |
| An electron acceptor is said to be ___________ | reduced |
| An electron donor is said to be __________because frequently their electrons are donated to O2 atoms. | oxidized |
| oxidation involves _____________ | Loss |
| reduction involves ___________ | Gain |
| Redox reactions always | occur simultaneously |
| Electrons rarely exist | freely in cytoplasm |
| Cells use _______ _______ _______ to carry electrons. (often in H atoms) | electron carrier molecules |
| THREE IMPORTANT ELECTRON CARRIERS | 1. Nicotinamide adenine dinucleotide (NAD+)> NADH 2. Nicotinamide adenine dinucleotode phosphate (NADP+)>NADPH 3. Flavine adenine dinucleotide (FAD)>FADH2 |
| ATP is for | Short Term Energy Storage |
| Cells phosphorylate | ADP to ATP (Energy In) |
| Anabolic Pathways (ie for Synthesis) use | some energy of ATP by breaking a phosphate bond. |
| Enzymes are | Organic Catalysts |
| Catalyst | increase the rate of a reaction without being consumed in the process. |
| Apoenzymes are | inactive if not bound to non-protein cofactors (e.g. inorganic ions, iron zinc, copper, etc.), or coenzymes (e.g. vitamins) |
| Binding of apoenzyme and its cofactors yields | holoenzyme |
| the activity of enzymes depends on the closeness of fit between the functional site (________) of an enzyme and its substrate. | Active Site |
| The shape of an enzymes active site is | complementary to the shape of the substrate. |
| Induced Fit Model | An enzymes active site is complementary to the shape of it substrate, but a perfect fit between enzyme and substrate does not occur until thy bind to form a complex |
| Factors that influence the rate of enzymatic reactions | 1. Temperature (dont forget that proteins can be denatured at high temps) 2. PH 3. Enzyme and Substrate concentrations 4. Presence of Inhibitors (Substances that block an enzyme site) |
| Enzyme Inhibitors | 1. Competitive 2. Noncompetitive 3. Negative Feedback |
| Noncompetitive Inhibitors | Bind to the allosteric site rather than active site and alter the shape of the active site. (can inhibit or activate) |
| Feedback Inhibition | the end product of a metabolic pathway inhibits the initial step of the pathway |
| Pathways have ________ __________. | multiple reactions |
| Microbial Growth | Increase in the size of a population of microbes rather than an increase in the size of individuals. |
| Result of microbial growth is | discrete colony, an aggregation of cells arising from a single parent cell |
| Organisms use a variety of _______ from a variety of sources for ________ and __ ____ ______ ________ and cellular structures. | nutrients, energy, to build organic molecules |
| Trophic | Food/Feeding |
| Autotrophs | inorganic source of Carbon (ie CO2)(auto=self)(plants) |
| Heterotrophs | organic sources of Carbon (hetero=other)(humans) |
| Chemotrophs | use chemicals as a source of energy (chemo=chemical)(Humans) |
| Phototrophs | use light as a source of energy (photo=light)(plants) |
| Photoautotrophs | plants,algae, and cyanobacteria |
| Chemoautotrophs | bacteria, and some archea |
| Photoheterotrophs | Green and purple nonsulfur bacteria, and some archea |
| Chemoheterotrophs | 1.Aerobic respiration: most animals, fungi, and protozoa, and many bacteria 2.Anaerobic respiration:some animals, protozoa, bacteria, and archea 3.Fermentation:some bacteria, yeasts, and archea |
| Obligate aerobes | require O2 |
| obligate anaerobes | die in the presence of O2 |
| ROS | reactive oxygen species |
| ROS are by-products of metabolic reactions and they are | highly reactive and excellent oxidizing agents |
| oxidation | causes irreparable damage to cells |
| Aerobes have various enzymes that ___________ROS but anaerobes do not! | destroy |
| Facultive anaerobes | can use O2 but also grow without it |
| Aerotolerant | do not use O2 but can grow when it is present |
| Microaerophiles | require O2 but grow only in concentrations lower than air |
| Nitrogen makes up __% of the ___ _____of _________ ____ | 14, dry weight, microbial cells |
| Nitrogen is often a ________-_________ _______ for many organisms and their anabolism ceases due to insufficient nitrogen | growth-limiting nutrient |
| All Cells _____ _______from amino acids and nucleotides. | recycle nitrogen |
| nitrogen fixation by | certain bacteria is essential to life on Earth. |
| Other chemical requirements for microbial growth | Phosphorus, Sulfur, and trace elements |
| Psychrophiles | "cold loving" grow best at temps below 15C |
| Mesophiles | "moderate temp loving" grow best at temps from 20C to 40C. |
| Thermophiles | "heat loving" grow at temps above 45C |
| hyperthermophiles | "above heat loving" grow at temps above 80C-100C |
| Each of the microbes that grow based on temperature | have a minimum, optimum, and maximum growth temperature. |
| Neutrophiles | grow best in a narrow range around neutral PH |
| Acidophiles | grow best in acidic habitats |
| Alkalinophiles | live in alkaline soils and water. (vibrio cholerae) |
| Most cells die in the absence of ________. | water |
| Inoculum | sample introduced into/onto medium |
| Medium | liquid or gel designed to support the growth of microorganisms.(broth,agar plates,agar slants, deeps) |
| CFU | Colony forming unit |
| two common isolation techniques | streak plates (get individual colonies), pour plates |
| Six Types of general culture media | 1.defined media 2.complex media 3.selective media 4.differential media 5.anaerobic media 6.transport media |
| defined media | exact chemical composition is known |
| complex media | contains nutrients released from partial digestion of yeast, beef, soy, etc. (exact composition unknown) |
| selective media | have chemicals that either favor growth or inhibit growth of a particular bacteria |
| differential media | have constituents that allow you to differentiate between different groups of bacteria. (MacConkey) |
| anaerobic media | protect anaerobes from free O2(GasPak anaerobic system) |
| transport media | used for transporting clinical specimens |
| obligate intracellular parasites | bacteria that need to be cultured in living animal cells |
| low-oxygen culture | mimic atmosphere in the respiratory tract |
| canophiles | bacteria that grow best in higher concentrations of CO2 |
| Enrichment culture | enhance the growth of a particular bacteria |
| Ways to preserve cultures | Refrigeration, deep-freezing, lyphilization(freeze drying) |
| Most bacteria reproduce by | binary fission (4 steps) |
| 4 steps of binary fission | 1. Cell replicates chromosome 2. Cell Elongates and growth of the wall pushes chromes apart 3.Cells form new cytoplasmic membranes 4.Daughter cells may remain attached or separate completely. |
| septum formation | the cell wall that grows between a mother and daughter cell during binary fission |
| average generation time for bacteria is | 1-3 hours |
| exponential or logarithmic growth | the rate of binary fission for bacteria growth |
| 4 phases of bacterial growth | 1.Lag phase 2.Log phase 3.Stationary phase 4.Death phase |
| Lag phase | making new enzymes in response to new medium |
| Log phase | logarithmic or exponential growth |
| Stationary phase | nutrients becoming limited or waste products becoming toxic. (death rate=division rate) |
| Death phase | death exceeds division |
| Direct method of measuring microbial reproduction | direct counting of cells |
| Direct methods of counting microbial populations | 1.Serial dilution and viable plate counts 2.Membrane filtration 3.Microscopic counts 4.Most probable number method 5.Electronic counters |
| Indirect methods of counting microbial populations | 1.Turbidity 2.Metabolic Activity 3.Dry Weight |
| Genetic method of counting microbial growth | Isolate DNA sequences of prokaryotes that cant be cultured in the lab. |
| DNA and RNA are | the genetic material of organisms |
| DNA carries instructions for synthesis of ______and _______ | RNA,proteins |
| RNA involved with ______ ________ and other functions. | protein synthesis |
| Both DNA and RNA are | unbranched macromolecular polymers |
| Genetics | Study of inheritance and inheritable traits. |
| Genome | The complete set of genetic instructions for an organism. |
| Genotype | the set of genes in an organisms genome |
| Phenotype | the physical features and functional traits of the organism (what you see) |
| Genotype + Environment = | Phenotype |
| Prokaryotic cells are | haploid(single chromosome) |
| Eukaryotic cells are | diploid (more than one chromosome) |
| A typical prokaryotic chromosome is a circular molecule of DNA in the region of cytoplasm called the ____________ | Nucleoid |
| Plasmids | Small molecules of DNA that replicate independently of the chromosome. |
| Plasmids are usually | circular and 1 to 5% of the size of the bacterial chromosome. |
| Resistance Plasmids | carry genes for drug resistance |
| Virulence Plasmids | carry genes that enable bacteria to be pathogenic (genes for toxin production) |
| Eukaryotic chromosomes are typically | linear and located within the nucleous |
| Eukaryotic cells are often | dipliod |
| Eukaryotes also have | extranuclear DNA (DNA molecules of mitochondria and chloroplasts) |
| Some fungi and protozoa carry | plasmids |
| Cells must continually _________ __________ required for growth, metabolism, reproduction, and regulation | synthesize proteins |
| Cells must accurately transfer the genetic info contained in ____ ___________ ___________ to the amino acid sequences of polpeptides. | DNA nucleotide sequences |
| Transcription | Genetic code from DNA is copied as messenger RNA (mRNA) |
| Translation | Genetic code copied as mRNA is used by ribosomes to synthesize polypeptides. |
| Central Dogma of Genetics | DNA transcribed to RNA and RNA translated to form polypeptides > proteins. |
| ____% bacterial genes are expressed at all times | 75 |
| Other genes ____________ and _______________ only when the cells need them. | transcribed , translated |
| Bacteria can acquire DNA from other bacteria these three ways | 1.Transformation 2.Transduction 3.Conjugation |
| Mutation | a permanent change in the nucleotide base sequence of a genome. |
| mutation is almost always | deleterious (harmful) |
| Point mutations | single base of gene sequence is substituted |
| mutations are | rare events |
| mutagens increase | the mutation rate by a factor of 10 to 1000 times. |
| Mutagen | an agent that causes DNA to mutate.(radiation, chemical mutagens) |
| Transformation transfer | recipient takes up DNA from the environment |
| Frederick Griffin | discovery of transformation transfers |
| Transduction | transfer of DNA from one cell to another via a bacteriophage. |
| bacterial conjugation | mediated by a conjugation pilus including transfer of a fertility plasmid |
| virulence factor genes | genes that can make bacteria more virulent |
| virulence factors include: | fimbrae, toxins, antibiotic resistance |
| virulence factor genes tend to congregate on | pathogenicity islands |
| Sterilization | the removal or destruction of ALL microbes, including bacterial endospores and viruses, in or on an object. |
| Aseptic | describes an environment or procedure that is free of contamination by pathogens. |
| Disinfection | refers to the use of PHYSICAL or CHEMICAL AGENTS known as DISINFECTANTS, including UV light, alcohol, and bleach to inhibit or destroy microorganisms, especially pathogens. |
| Disinfection _______ ____ guarantee that all pathogens are eliminated. | does not |
| Disinfection is a term used when discussing treatment of _________ ________. | inanimate, objects |
| Antisepsis | chemical destruction of pathogens on living tissue |
| Degerming | mechanical removal of microbes from a surface by scrubbing. (i.e. hand washing, alcohol swabbing) |
| Sanitization | lowering the microbial counts on eating and drinking utensils to safe levels |
| Pasteurization | the use of heat to kill pathogens and REDUCE THE NUMBER of spoilage microorganisms in food and beverages; note some microbes still remain and eventually caue food spoilage. |
| stasis/static | indicates a chemical or physical agent that inhibits microbial metabolism and growth, but doesn't necessarily kill microbes . (i.e. refrigeration) |
| cide/cidal | refers to agents that destroy or permanently inactivate a particular type of microbe. |
| Virucides | inactivate viruses |
| Bactericides | kill bacteria |
| Fungicides | kill fungus |
| Germicides | destroy pathogenic microbes in general |
| Action of Antimicrobial Agents | 1. Disrupt the integrity of cells by adversely altering their cell walls and membranes. 2. Interrupt metabolism and reproduction by damaging proteins and nucleic acids. |
| Heat Related Microbial Control Methods | 1. Moist Heat 2. Boiling 3. Autoclaving 4. Dry Heat |
| Thermal Death Point | the lowest temp that kills all cells in broth in 10 min. |
| Thermal Death Time | the time it takes to sterilize a particular volume of liquid at a set temp |
| Methods of microbial control using moist heat | 1. Boiling 2. Autoclaving 3. Pasteurization 4. Ultahigh temperature sterilization |
| Boiling temperature increase as | pressure increases |
| To ensure that an autoclave has sterilized its contents | 1. use chemical embedded tape or paper 2. use a sterility indicator |
| Pasteurization | heating just enough to destroy the microorganisms that cause rapid spoilage. |
| Ultrahigh-temperature sterilization | 140C for 1-3 seconds, then rapid cooling. |
| Dry Heat method | (160-170C) for longer time than moist heat |
| Refrigeration and freezing methods | decrease microbial metabolism, growth, and reproduction. |
| Refrigeration halts | growth of most pathogens |
| Dessication (Drying) | Drying inhibits growth due to removal of water |
| Lyophilization (Freeze Drying) | is used for long term preservation of microbial cultures |
| Filtration microbial controls are | used when an item cannot withstand heat sterlization |
| Osmotic Pressure Microbial Controls are | useful for preservation of foods like honey, jam, jelly, jerky, salted fish, etc. |
| Biosafety Levels by CDC | 1. Level 1- handling pathogens that don't cause disease. 2. Level 2- handling moderately hazardous agents(hepatitis, flu) 3. Level 3-handling microbes in safety cabinets (anthrax) 4. Level 4-handling microbes that cause severe or fatal disease(Ebola vi |
| Chemical methods of Microbial Control often | are more effective against vegetative cells of bacteria, fungi, and protozoa and some viruses |
| Phenol and Phenolics are | Intermediate to low level disinfectants |
| Alcohols are | Intermediate level disinfectants |
| Halogens are | chemical elements (iodine, chlorine, bromine, fluorine) |
| Oxidizing Agents are | peroxides, ozone, peracetic acid |
| Surfactants reduce | surface tension of solvents so solvents become effective at dissolving solutes(soaps and detergents) |
| Antimicrobials | antibiotic=antimicrobial chemicals produced naturally by microorganisms(used in treatment of disease) |
| Aldehydes, glutaraldehyde, and formaldehyde | denature proteins and inactivate nucleic acids(disinfect, sterilize, embalm) |
| Gaseous Agents are use only in | closed chambers |
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tla1957
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