Microbiology Exam 2
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Created by:
melcherj on October 3, 2010
Subjects:
metabolism, nutrition, and genetics
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57 terms
Terms | Definitions |
|---|---|
 Nutrition | process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities |
| Macronutrients | required in large quantities; play principal roles in cell structure and metabolism. (proteins, carbohydrates) |
| Micronutrients or Trace Elements | required in small amounts; involved in enzyme function and maintenance of protein structure (manganese, zinc, nickel) |
| Heterotroph | must obtain carbon in an organic form made by other living organisms such as proteins, carbohydrates, lipids, and nucleic acids |
| Autotroph | an organism that uses CO2 an inorganic gas its carbon source (not nutritionally dependent on other living things) |
| Photoautotrophs | oxygenic photosynthesis, anoxygenic photosynthesis |
| Chemoautotrophs (lithoautotrophs) | survive on inorganic substances |
| Phototrophs | gain energy through photosynthesis |
| Chemotroph | gain energy from chemical compounds |
| Saprobes | free-living microorganisms that feed on organic detritus from dead organisms *Opportunistic pathogen *Facultative parasites |
| Parasites | derive nutrients from host *pathogens, some are obligate parasites |
| Growth Factors | organic compounds that cannot be synthesized by an organism because they lack the genetic and metabolic mechanisms to synthesize them -must be provided as a nutrient *essential amino acids, vitamins |
| Passive Transport | does not require energy; substances exist in a gradien and move from areas of higher concentration towards areas of lower concentration |
| Active Transport | requires energy and carrier proteins; gradient independent |
| Group Translocation | transported molecule chemically altered |
| Bulk Transport | endocytosis, exocytosis, and pinocytosis |
| 3 Cardinal Temperatures | Minimum temperature- lowest temp that permits a microbe's growth and metabolism Maximum- highest temp that permits a microbe's growth and metabolism Optimum- promotes the fastest rate of growth and metabolism |
| 3 Temperature Adaptation Groups | Pyschrophiles- optimum temperature below 15 degrees C capable of growth at 0 degrees C Mesophiles- optimum temp 20-40 degrees C; most human pathogens Thermophiles- optimum temp greater that 45 degrees C |
| Aerobe | utilizes oxygen and can detoxify it |
| Obligate aerobe | cannot grow without oxygen |
| Facultative anaerobe | utilizes oxygen but can also grow in its absence |
| Microaerophilic | requires only a small amount of oxygen |
| Anaerobe | does not utilize oxygen |
| Obligate anaerobe | lacks the enzyme to detoxify oxygen so cannot survive in an oxygen environment |
| Aerotolerant anaerobes | do not utilize oxygen but can survive and grow in its presence |
| Capnophile | grows best at higher CO2 tensions than normally present in the atmosphere |
| Most microorganisms grow at which pH level? | pH between 6 and 8 |
| Association with other organisms | Microbes live with other microbes and potentially with hosts -May be symbiotic with mutualism, commensalism, or parasitism or nonsymbiotic with synergism or antagonism |
| Biofilms | thin slimy film of bacteria that adheres to a surface have important medical consequences |
| Lag Phase | "flat" period of adjustment, enlargement; little growth |
| Exponential growth phase | a period of maximum growth will continue as long as cells have adequate nutrients and favorable environment |
| Stationary phase | rate of cell growth equals rate of cell caused by depleted nutrients and O2, excretion of organic acids and pollutants |
| Death phase | as limiting factors intensify, cells die exponentially in their own wastes |
| Counting bacteria | -Direct microscopic count of bacteria -Using a spectrophotometer -Coulter counter -Viable plate count |
| Metabolism | The chemical reactions whereby energy is provided for cell processes and components, such as: Motility, transport of nutrients, growth/reproduction |
| Catabolism | degradative; breaks the bonds of larger molecules forming smaller molecules; releases energy |
| Anabolism | biosynthesis; process that forms larger macromolecules from smaller molecules; requires energy input |
| Enzymes | biological catalysts that increase the rate of a chemical reaction by lowering the energy of activation |
| Substrate-level phosphorylation | transfer of phosphate group from a phosphorylated compound (substrate) directly to ADP |
| Oxidative phosphorylation | series of redox reactions occurring during respiratory pathway |
| Photophosphorylation | ATP is formed utilizing the energy of sunlight |
| EMP Glycolysis | In the cell, no oxygen needed, gain 2 ATPs/glucose, NADHs need to be recycled (fermentation or electron transport chain) |
| Kreb's cycle | Results Pyruvate is oxidized to CO2 Electron transfers to NAD and FAD These must be recycled: in ETC Some substrate level phosphorylation -Can also generate intermediates -Bacteria: in cytoplasm -Eucaryotes: in mitochondria |
| Transcription | process by which information stored on the DNA molecule is conveyed to RNA molecules |
| Translation | process by which the information contained in the RNA molecule is then used to produce proteins |
| Replication | the process by which genetic material or and organism gives rise to a copy of itself Making an exact duplicate of the DNA involves 30 different enzymes Single, circular chromosome First have to relieve supercoiling using Gyrase 1. Begins at an origin of replication |
| Genome | Genome - sum total of genetic material of a cell (chromosomes + mitochondria/chloroplasts and/or plasmids) Genome of cells - DNA Genome of viruses - DNA or RNA |
| Genes | the fundamental unit of heredity responsible for a given trait. site on the chromosome that provides information for a certain cell function segment of DNA that contains the necessary code to make a protein or RNA molecule |
| 3 categories of genes | Three basic categories of genes: 1. Genes that code for proteins - structural genes 2. Genes that code for RNA 3. Genes that control gene expression - regulatory genes |
| Genomes vary in size | Smallest virus - 4-5 genes E. coli - single chromosome containing 4,288 genes; 1 mm; 1,000X longer than cell Human cell - 46 chromosomes containing 31,000 genes; 6 feet; 180,000X longer than cell |
| Helicase | unzips the DNA double helix |
| DNA Polymerase III | adds nucleotides in a 5′ to 3′ direction proofreads the matches |
| leading strand | synthesized continuously in 5′ to 3′ direction |
| lagging strand | synthesized 5′ to 3′ in short segments; overall direction is 3′ to 5′ Called Okazaki fragments- segments less than a thousand base pairs DNA Pol III also proofreads the matches |
| DNA Polymerase I | removes the RNA primers and replaces them with DNA. |
| Ligase | link the DNA fragments along the lagging strand to complete the synthesis. |
| Gyrase | catalyzes relaxation for unwinding |
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