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Micro Test notes 2
Microbiology
| Question | Answer |
|---|---|
| Necessary for growth, primary component of cell structure. | Water |
| Types of environments? | Hypotonic, Isotonic, and Hypertonic |
| Water flows into the cell and cell eventually explodes | Hypotonic environment |
| Water flows out of the cell and cell shrinks and dies | Hypertonic environment |
| microbes are able to live/adapt to mildly hypertonic environments | osmotolerant |
| Microbes require extreme hypertonic environments to survive | osmophilic |
| Microbes living in the dead sea, great salt lake and adapt by using salts as necessary integral components of cell structure. | Halophiles (osmophilic) |
| A measure of Hydrogen ion concentration | pH 0-14 |
| pH 0-5.5, fungi, algae, helicobacter pylori, acidic environment, use active transport to pump out excess hydrogen ions, create acid shock proteins that help prevent denaturation if cytoplasm is to acidic. | Acidophites |
| High pH | alkaline, basic, low hydrogen concentration |
| Low pH | Acidic, high hydrogen concentration |
| pH 5.5 to 8.5, most microbes, hydrogen ions flow evenly by facilitated diffusion | Neutrophiles |
| pH 8.5 to 14, only bacteria, alkaline environment, use active transport to pump hydrogen ions back into the cell. | Alkalophiles |
| Poikilotherms (varied irregular heat), temp varies with environment | Temperative |
| Cardinal Temps | a minimum temp for growth. a optimum temp for growth. a maximum temp for growth. |
| Classes of Microbes by Temp | Psychophiles, Psychrotrophs, Mesophiles, Thermophiles, Hyperthermophiles. |
| microbes found living on glaciers and snowfields, Chlamydomonas nivalis (watermelon snow), not human pathogens, have and increased concentration of unsaturated fatty acids in plasma membrane. | Psychophiles |
| Main cause of food spoilage in the fridge, cause off color, smell, bad taste etc. not significant human pathogens | Psychrotrophs |
| Most microbes are in this group including human pathogens. | Mesophiles |
| Found in hot water springs, pipes, hot springs, compost piles, not human pathogens, important in biotechnology, heat stable enzymes, TAQ polymerase used to copy DNA in PCR(Polymerase chain reaction). | Thermophiles |
| Found in deep sea hydrothermal vents, volcanic springs, pyrococcus abyss, adapt by increase concentration of saturated fatty acids in plasma membrane. | Hyperthermophiles |
| With oxygen | Aerobic |
| Without oxygen | Anaerobic |
| Use aerobic respiration for growth, growth is quicker but creates free radicals which must be destroyed by creation of enzymes, to prevent cell damage. | Aerobic cells |
| Use anaerobic respiration or fermentation for growth, although growth is slower, no free radicals to worry about | Anaerobic cells |
| Classes of Microbes by Oxygen | Obligate aerobes, Facultative anaerobes, Aero-tolerant anaerobes, Microaerophiles. |
| Microbes will die if oxygen not present. Top of tube. | Obligate aerobes |
| If oxygen present microbes will use it and grow most quickly if oxygen is not present growth is slower. Microbes throughout tube although more prominent at top. | Facultative anaerobes |
| Do not use oxygen grow equally well with or without oxygen. Evenly throughout tube. | Aero-tolerant anaerobes |
| Require oxygen but at reduced concentration 2-10% atm. Bacteroides gingivalis. Fine line of microbial growth somewhere near top of tube. | Microaerophiles |
| Microbes are able to survive and grow up to a max of about 400 atm but grow more quickly at lower pressure. | Barotolerant |
| Thriving under high environmental pressure | Barophilic |
| Expose food to rapid changes in pressure to control growth of pathogens in food. | High Pressure Pasteurization (HPP) |
| Three basic nutritional requirements for microbial growth? | Source of nutrients, energy and electrons or hydrogen atoms that donate electrons. |
| MIcrobes that create every compound for growth, assuming 3 basic nutritional requirements are available. | Prototrophs |
| Cannot create every compound for growth, need growth factors. | Auxothrops |
| Vitamins, amino acids, purines, pyramidines. | Growth factors |
| Has the ability to store information, information can be copied/replicated and passed to offspring. | DNA (deoxyribose neucleic acid) |
| The subunits that compose DNA? | Nucleotides |
| Each nucleotide has three components. | 5 carbon sugar (in DNA deoxyribose)(in RNA ribose), phosphate group, and nitrogenous group. |
| In DNA nucleotides 4 possible nitrogenous bases? | adenine, guanine, thymine, cytosine. |
| Purine | Double ring, adenine+guanine |
| Pyrimidine | Single ring, Thymine+Cytosine |
| In RNA 4 possible nitrogenous bases? | adenine, guanine, cytosine, uracil. |
| DNA is like a ladder side rails? | Alternating phosphate and sugars |
| DNA is like a ladder rungs? | Nitrogenous bases |
| Adenine+Thymine | 2 H bonds |
| Cytosine+Guanine | 3 H bonds |
| The entire sequence of DNA in an organism? | Genome |
| Genome is divided into 2 general regions? | Gene, and Non transcribed region. |
| Region of DNA that is transcribed into single messenger RNA and translated into a polypeptide (protein product) | Gene |
| Includes many regions with currently unknown functions and promoters= non transcribed region of DNA that control gene expression (how often a gene gets used). | Non transcribed region |
| The synthesis of RNA under the direction of DNA. DNA template to create a mRNA (complementary)of the DNA. | Transcription |
| Use mRNA to create the appropriate polypeptide. | Translation |
| In translation mRNA is read in blocks of nucleotides. | Codons, each codon specifies codes for a particular amino acid. |
| Two basic mechanisms to generate genetic diversity. | Mutation, and genetic recombination |
| A stable heritable change in DNA sequence. | Mutation |
| One sequence is altered does not change back. | Stable mutation |
| Change in DNA sequence are passed to offspring | Heritable mutation |
| A change in DNA sequence that is harmful or adverse for the organism. (e.g. mutation inhibits/blocks ability to create glycocalyx) | Negative mutation |
| Change in DNA sequence that neither harms or benefits the organism. Could result from redundancy in genetic code. | Silent mutation |
| Change in DNA sequence that alters a structural feature of the organism (e.g. cell shape, size, cell wall). | Morphological mutation |
| Change in DNA sequence that alters a biosynthetic or other enzymatic pathway (e.g. microbe loses the ability to create folic acid a vitamin required for growth). Could cause a prototroph to become axotroph. | Biochemical mutation |
| Change in DNA sequence that only effects the microbe in specific environments. (e.g. ability to create penicillinase). Only beneficial with penicillin present. | Conditional mutation |
| Change in DNA sequence that alters the identity of one or more nucleotide base pairs does not alter total number of nucleotides. | Base substitution |
| A base substitution in DNA may lead to changes in the polypeptide product. | Missense mutation, nonsense mutation, silent mutation, frameshift mutation. |
| Change in DNA sequence that alters the identity of one or more amino acids in the polypeptide product. | Missense mutation |
| Change in DNA sequence that eliminates the start codon or creates a premature stop codon. | Nonsense mutation |
| Change in DNA sequence that does not alter the polypeptide product (due to redundancy). | Silent mutation |
| Occurrence of linearly arranged, largely identical, repeated sequences of DNA. | Redundancy |
| Change in DNA sequence in which one or more nucleotide base pairs are inserted into or deleted from the sequence also alters the total number of nucleotides. Could lead to missence mutation, nonsense mutation, or silent mutation. | Frameshift |
| Two cause of mutation? | Spontaneous mutation and induced mutation |
| A change in DNA sequence that occurs during DNA replication due to error by the polymerase. Relatively rare 1 in 1,000,000 genes copied | Spontaneous mutation |
| Enzyme that copies the DNA during transcription. | Polymerase |
| A change in DNA sequence caused by exposure to a mutagen (any chemical or physical factor that alters the DNA sequence). Nitrous acid causes base substitution, and benzpyrene causes frameshifts. Higher frequency 1 in 1000 genes copied. | Induced mutation |
| Genetic diversity is created by? | mutation or genetic recombination |
| In Eukaryotes genetic recombination occurs by? | Sexual reproduction |
| The process by which a strand of genetic material (usually DNA; but can also be RNA) is broken and then joined to a different DNA molecule. | Genetic recombination |
| In prokaryotes genetic recombination occurs by? | One way transfer of DNA from a donor to a recipient cell. |
| 3 mechanisms of one way transfer. | Conjugation, transformation, and transduction |
| One way transfer of DNA between two cells in temporary physical contact, physical contact created by the sex pilus. | Conjugation |
| First evidence of conjugation | 1946 Lederberg and Tantum |
| The uptake of naked DNA by a competent cell. Uptake by modified sex pillus. | Transformation |
| First evidence of transformation. | 1928 injection of mice with S. Pneum. with capsule mouse dies, without capsule mouse lives,with capsule killed by heat mouse lives. |
| One way transfer of DNA from donor to recipient by a bacteriaphage (a virus that infects bacteria). | Transduction |
| A process that removes or destroys all vegetative cells (dormant, bacteria, fungi, algae, protozoans), endospores and viruses. | Sterilization |
| A process that removes destroys or inhibits the growth of disease causing (pathogenic) microbes. | Disinfection |
| A process that reduces microbial number to a level considered safe by the public health standards. | Sanitation |
| A process that removes destroys or inhibits the growth of pathogenic microbes on living tissues. Not as strong as disinfectants would not damage skin. | Antiseptics |
| Anti-microbial agents vary | Range in action, and strength of action. |
| Strength of action may be | cidal or static. |
| Agent kills the target microbes | Cidal |
| Agent inhibits the growth of the target microbes (e.g. germ static vs. fungicidal) | Static |
| Factors that affect efficiency of antimicrobial agents. | Duration of exposure, Presence of organic debris, and surface features, temperature, concentration, population size, population composition. |
| Chemical anti-microbial agents capable of sterilization. | Aldehydes and Sterilizing gases. |
| 2 main types of antimicrobial agents. | Chemical agents and physical agents |
| Most are capable of sterilization most can only disinfect. | Chemical agents |
| Most are capable of sterilization | Physical agents |
| Physical antimicrobial agents | Heat, Autoclaving, Boiling water, Fractional steam sterilization, dry heat sterilization, Pasteurization, Filtration, and radiation. |
| How would you know if autoclave is working properly? | Autoclave tape, growth check, endospore strip. |
| 3 day process that kills all endospores | Fractional steam sterilization |
| Commonly used for items such as metal or glass that would corrode from moist heat. Typical run 160-170 degrees celsius for 2-3 hrs. Without moisture both time and temp required to sterilize increase. | Dry heat sterilization |
| Goal is to destroy pathogenic microbes and microbes that would spoil the food without altering taste, texture, nutritional quality of the food. | Pasteurization |
| Used for heat sensitive liquids. | Filtration |
| Types of Filtration | Depth filtration, and Membrane filtration |
| Composed of fibrous or granular materials compacted into a thick layer. | Depth Filtration |
| Composed of a thin layer with holes of a defined size. Membrane filter traps any microbe larger that the pore size (e.g. fecal coli forms) | Membrane Filtration |
| HEPA filters pore size | 0.45 nm |
| Smallest filter pore size | 0.01 nm |
| Use to sterilize heat sensitive plastics, suture material, tubing, hormone solutions, vaccinations, medical waste, surgical instruments. Energy disrupts chemical bonds and causes denaturation. | Radiation |
| Relatively lox energy poor penetration, but can cause lethal DNA mutations. Microbes must be directly exposed to cause damage. | Ultra Violet Radiation (UV) |
| Uses an electron accelerator to shoot a stream of electrons at items to be sterilized. Higher energy than UV penetration about 2 inches, currently used to sterilize medical and clinical supplies and water. | E-Beams (electron) |
| Created using electron accelerator to create photons (no mass). Higher energy than E-Beams, also used to sterilize clinical supplies. | X-Rays |
| Photons given off from the decay of certain radioactive elements (e.g. cobalt 60). Highest energy best penetration for sterilization. | Gamma Rays |
Created by:
Hector1006
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