Flashcards About Microbiology
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| nutrient that must be provided |
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| essential nutrient |
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| nutrient that must be supplied in large amounts |
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| macronutrient |
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| nutrient that lacks carbon and hydrogen |
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| inorganic nutrient |
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| nutrient that contains carbon and hydrogen |
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| organic nutrient |
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| primary energy source is sunlight |
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| photo- autotroph or heterotroph |
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| primary energy source is a chemical compound |
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| chemo- autotroph or heterotroph |
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| use inorganic substances for energy |
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| autotrophs |
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| use organic substances for energy |
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| heterotrophs |
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| ideal solute state of a cell |
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| hypotonic |
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| solute concentration is lower on the outside of the cell |
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| hypotonic |
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| solute concentration is lower on the inside of the cell |
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| hypertonic |
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| uses oxygen during metabolism and can process toxic oxygen and byproducts |
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| aerobe |
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| does not require oxygen to grow, but favors it |
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| facultative anaerobe |
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| cannot grow in normal atmospheric concentrations of O2, but does need small amounts for metabolism |
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| microaerophile |
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| lacks ability to utilize O2 during metabolism |
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| anaerobe |
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| does not utilize O2 but can grow in the presence of O2 because it can process toxic O2 byproducts |
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| aerotolerant anaerobe |
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| relationship is necessary and mutually beneficial |
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| mutualism |
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| one oragnism benefits while the other is neither benefited nor harmed |
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| commensalism |
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| both organisms benefit, but it is not necessary for either organism's survival |
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| synergism |
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| organisms live together in a close relationship |
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| symbiosis |
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| one organism recieves nutrients from and at the expense of the other |
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| parasitism |
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| organisms living together compete for nutrients |
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| antagonism |
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| time it takes to go from a single cell to two daughter cells |
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| generation/doubling time |
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| processes that result in the synthesis of cell molecules and structures; usually requires energy |
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| anabolism |
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| processes that result in the break down of the cell molecules and structures; usually releases energy |
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| catabolism |
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| macromolecules that increase the rate of a chemical reaction without being a product or reactant |
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| enzyme |
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| the amount of energy necessary for the reaction to occur |
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| activation energy |
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| enzymes that consist soley of protein |
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| simple enzyme |
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| site on the enzyme where substrates bind and the reaction occurs |
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| active site |
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| only certain substrates can bind to an enzyme due to constarints of the active site on physical characteristics such as size, shape, and charge |
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| lock-and-key model |
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| enzymes that function outside the cell; often involved in breaking down nutrients or wastes |
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| exoenzymes |
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| enzymes that function inside the cell; most metabolic enzymes |
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| endoenzymes |
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| enzymes that are not always present |
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| constitutive enzymes |
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| enzymes which presence can be turned on or turned off |
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| regulated enzymes |
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| enzymes that form covalent bonds between substrates |
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| ligases |
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| enzymes that remove electrons from one substrate and add them to another; NAD and FAD often serve as coenzymes |
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| oxidoreductases |
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| enzymes that catalyze steps of metabolic regulation that "set the pace" for the entire pathway |
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| pacemakers |
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| chemical reactions that release energy |
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| exergonic |
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| chemical reactions that require energy |
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| endergonic reactions |
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| enzymes that breakdown proteins into amino acids |
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| proteases |
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| removal of amino group from amino acids so that carbon backbone can be shuttled into Krebs cycle |
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| deamination |
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| sum of the genetic material within a cell or organism |
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| genome |
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| the basic functional units of the genetic material |
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| genes |
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| the study of genes |
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| genetics |
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| all the genes that make up an organism's genetic material |
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| genotype |
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| all the traits that characterize an organism; can change according to gene expression |
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| phenotype |
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| region of DNA "upstream" of the begining of the gene |
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| promoter |
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| set of genes that are regulated simutaneously in prokaryotes |
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| operon |
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| bind to the promoter region of a gene where they recruit RNA polymerase to promote transcription |
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| transcription factors |
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| a change in the DNA that results in a change in phenotype |
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| mutation |
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| an unaltered phenotype |
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| wild type |
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| an altered phenotype due to mutation |
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| mutant |
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| a physical or chemical agent that damages DNA |
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| mutagen |
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| what is being transferred during conjugation; can be either plasmid or chromosomal DNA |
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| F factor |
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| cells capable of accepting the free DNA |
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| competent |
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| process similar to transformation in eukaryotes |
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| transfection |
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| sections of DNA that can jump from one location in the chromosome to another, from chromosome to plasmid, or from plasmid to chromosome |
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| transposons |
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| destruction of all microbial life |
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| sterilization |
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| destruction of most microbial life on an inanimate surface |
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| disinfection |
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| destruction of most microbial life on a living surface |
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| antisepsis |
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| mechanical removal of most microbes |
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| decontamination |
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| kill bacterial endospores |
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| sporicidal |
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| ability of the cell to reproduce and be metabolically active |
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| cell viability |
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| how do cells digest and absorb nutrients when they have a cell wall? |
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| through osmosis or diffusion |
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| explain the process of osmosis and diffusion |
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| movement of water across semipermeable membrane down concentration gradient; diffusion is movement of particles down concentration gradient that results from random motion of particles and their collisions with one another in space |
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| what are the three types of diffusion and how do they differ? |
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| simple- no barrier; facilitated- with help of carrier protein; active- can move up or down concentration gradient with help of carrier protein and requires energy |
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| what are the three mechanisms of active diffusion? |
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| carrier-mediated- carrier protein moves with or against concentration; group translocation- coupled with another reaction and molecule is chemically modified; bulk transport- large molecules or quantities |
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| which of the solute states of a cell is ideal for life? |
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| hypotonic |
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| explain how temperature might affect cell growth? |
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| different bacteria thrive in different temperatures; minimum, maximum, optimum |
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| besides temp what are three other environmental factors that affect microbial growth? |
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| gases, pH, osmotic pressure, radiation, hydrostatic pressure, water content |
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| equation of microbial growth |
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| Nf= (Ni) x 2^n |
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| how does an enzyme speed up a reaction? |
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| by lowering the threshold (the amount of energy required for a reaction to occur) |
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| describe synthesis/dehydration |
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| builds macromolecules; requires ATP; produce water; utilize ligase |
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| describe hydrolosis |
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| breaks down macrmolecules; requires water; releases ATP |
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| describe transfer reactions |
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| utilize oxidoreductases enzymes that remove electrons from one substrate and add them to another; NAD and FAD often serve as coenzymes |
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| How is metabolism regulated? |
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| by enzymes |
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| Describe competitive inhibition. |
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| a molecule resembling the substrate binds to the active site of an enzyme blocking the ability of substrate to bind |
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| describe noncompetitive inhibition |
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| a molecule binds to a site of the enzyme outside the active site to prevent or enhance activity of the enzyme |
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| what are the three major processes through which ATP is formed |
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| substrate-level phosphorylation, oxidative phosphorylation, photophosphorylation |
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| what are the major sources of energy in the cell |
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| carbs, proteins, and lipids |
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| What are the major macromolecular building blocks and what macromolecules do they build? |
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| monosacharides which build carbs, amino acids which build proteins, fatty acids which build lipids, nitrogen bases which build nucleic acids, and vitamins which build enzymes |
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| what is the purpose of glycolosis? |
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| to break down glucose |
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| what is the starting material of glycolosis? |
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| glucose (or another 6 carbon sugar) |
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| what are the products of glycolosis? |
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| 2 pyruvate, 2 ATP (net), 2 NADH, 2 H2O |
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| where does glycolosis take place? |
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| cytoplasm |
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| what is the pacemaker of glycolosis? |
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| 2nd phosphorylation step before the 6C sugar is split |
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| What is the purpose of the Kreb's cycle? |
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| harvest energy from pyruvate in the form of NADH and FADH2 |
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| what is the starting material of the Kreb's cycle? |
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| 2 pyruvate |
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| what are the products of the Kreb's cycle? |
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| 2 ATP, 2 FADH, 8 NADH, 6 CO2 |
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| where does the Kreb's cycle take place? |
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| Prok- cytoplasm; Euk-mitochondrial matrix |
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| what is the pacemaker in the kreb's cycle? |
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| pyruvate to acetyl CoA |
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| what is the purpose of the ETC? |
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| generate energy in the form of ATP from NADH and FADH2 (redox reactions) |
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| what is the starting material in the ETC? |
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| 10 NADH, 2 FADH2, and oxygen or other electron acceptor |
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| what are the products of the ETC? |
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| 3 ATP per NADH (30 total), 2 ATP per FADH2 (4 total), and water |
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| what is the purpose of photosynthesis? |
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| convert light energy to chemical energy |
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| what is the starting material of photosynthesis? |
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| CO2 and H2O |
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| what are the products of photosynthesis? |
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| fructose and O2 |
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| where does the ETC take place? |
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| Euk- mitochondrial membrane; Prok-cell membrane |
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| where does photosynthesis take place? |
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| chloroplasts; light dependent (grana); light independent (stroma) |
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| how do alcoholic and acidic fermentation differ? |
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| alcoholic yields ethanol or other alcohol and CO2, acidic yields some acid (lactic, acetic, succinic, or formic) but not CO2 |
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| what are the four major types of genes and how do they differ? |
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| structural - encode proteins that play an important role in cell structure; functional- encode proteins that play an important role in cell function; regulatory -encode proteins or RNAs that play an important role in gene expression; RNA - encode RNA that does not become translated into protein |
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| what makes up a nucleotide? |
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| phosphate, deoxyribose, and nitrogen base |
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| how are nucleotides attached to each other? |
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| Phophodiester bonds are the one that connect the nucleotides next to each other on the same strand. Weak hydrogen bonds join the two complementary nucleotides and thus the two strands of the DNA together. |
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| Which enzymes are involved in DNA replication and what are their roles? |
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| helicase- binds to DNA at the origin of replication where it binds to DNA and seperates the starnds; gyrase-proceeds in front of helicase to remove the super coils from the DNA; primase- synthesizes a RNA primer at the 3 prime ends of the template DNA; DNA polymerase- attaches at the site of the primer, can remove RNA primers and replace with DNA primers, can also proofread for errors; ligase- links Okazaki fragments |
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| In what direction is the template strand read? which direct is it made? |
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| read 5 to 3, made 3 to 5 |
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| How do the terms semiconservative, replication fork, leading strand, lagging strand and Okazaki fragment relate to DNA replication? |
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| semiconservative- two DNA molecules at end of replication consist of one starnd from old DNA molecule and one starnd of newly sythensized DNA; replication fork- where replication is occuring; leading strand- strand that is replicated continuously; lagging strand (Okazaki fragments)- strand that is synthesized in short fragments |
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| What is the major structural feature of the origin of replication? |
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| high concetration of adenine and thymine which is easier to break because it only had two H bonds |
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| What are the differences between RNA and DNA? |
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| DNA is double stranded, has a helix, has thymine, deoxyribose, and is super coiled, while RNA is single stranded, has a helix, has uracil, ribose, can bind to itself to form complex secondary and tertiary structures, and is transcribed from DNA |
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| describe different types of RNA |
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| mRNA- complementary copy of a gene translated by ribosomes to synthesize proteins; tRNA- recognizes a codon of mRNA and transfers the apporopriate amino acid to the growing peptide chain during translation; rRNA- forms complex 3D structures and provides structure and function to the ribosomal subunits; regulatory RNA- regulate gene expression by interacting with DNA or RNA; primer RNA- created by ligase to help in initiation of DNA replication; ribozymes- RNA enzymes that remove the introns from eukaryotic pre mRNA |
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| Which enzymes are involved in transcription and what are their roles? |
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| RNA polymerase- adds nucleotides to grwoing mRNA strand; topoisomerase- relieves supercoils ahead of polymerase |
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| In transcription, what direction is the template strand read? which direction is the mRNA strand generated? |
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| 3 to 5; 5 to 3 |
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| Explain what redundancy (in the context of translation) means and why it exists. |
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| a single amino acid can be coded for by multiple codons |
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| What is unique about the first tRNA used in translation |
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| it enters at the P site, while others enter at the A site |
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| What are the differences between prokaryotic and eukaryotic mRNA? |
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| In Euk, each mRNA encodes a single protein and the mRNA requires additional processing before translation, whil ein prok, each mRNA may encode for several proteins and does not require additional processing |
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| Describe how an inducible operon functions. |
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| What are the two major causes of mutation and how do they differ? |
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| spontaneous- random change due to error in mutation; induced- result from expose to a physical or chemical agent that damages DNA |
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| In what ways can mutagens cause DNA damage? |
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| insert across both strands of DNA causing distortion in DNA shape; insert durign replication to replace a normal nucleotide from inserting; cause strand breaks; can create bonds between adjacnt pyridimines |
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| what is a point mutation? |
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| addition, deletion, or substitution of a single base |
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| what is a missense mutation? |
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| a change in DNA sequence that causes a change in the amino acid coded for during translation |
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| what is a nonsense mutation? |
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| changes a normal codon to a stop codon causing premature termination of translation |
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| what is a silent muatation? |
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| a change in base sequence that does not alter the amino acid sequence of the protein |
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| what is a frame shift mutation? |
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| insertion or deletion of a base which will cause the reading frame of the DNA to change; insertion in multiples of three do not result in a frame shift |
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| What are the three major mechanisms of DNA damage repair? How/when is each used? |
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| mismatch repair- replaces a single mismatch base during replication; nucleotide excision repair- replaces a fragment of DNA at any point during a cell's lifetime; base excision repair- replaces a single nucleotide base at any time in a cell's lifetime |
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| What test is used to determine whether a compound is mutagenic? If a compound is mutagenic, what will its effect be on growth of cells in this test? |
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| AMES test; more cells will grow |
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| What two factors are most important for determining the amount of microbial death caused by a microbicidal agent? |
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| concentration and time |
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| What are the common cellular targets of microbicidal agents? |
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| cell wall, cell membrane, cellular synthetic process, specific proteins or enzymes |
