BIO-205 Topic 2 Study Guide

Agar
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Terms in this set (46)
Agar
Agar plates are used for growing cultures. Agar is seaweed.
Bacterial reproduction known as
Prokaryotic cells divide by binary fission.
Biofilms
Most microbes live in polysaccharide-encased communities called biofilms. Biofilms enhance bioremediation efforts and protect organisms against harmful chemicals. Examples of biofilms are- dental plaque and pond scum.
Define pure culture and a colony
All the bacterial cells that result from the replication of a single original bacterial species/organism. It allows the study of a single species. Colony is a group of bacteria or microorganisms grown on an agar medium.
Method for isolating bacteria
Streak plate method. It spreads out cells to separate. Obtains single cells so individual colonies can form.
How are bacterial cultures stored
Stored on agar slant in refrigerator, frozen in glycerol solution, freeze-dried.
Explain the stages of bacterial growth curve and characteristics of these stages
Lag Phase- microbial cells introduced. cells are maturing but not yet dividing. begin synthesizing enzymes required for growth. metabolically active cells. number of cells does not increase.
Exponential or Log Phase- bacteria are rapidly increasing in number. most susceptible to antibiotics. production of primary metabolites (amino acids, ethanol) important commercially. secondary metabolite (example antibiotics). formation of endospores, capsules.
Stationary Phase- nutrient levels too low to sustain growth. total numbers remain constant. some die, release contents; others grow and become drug resistant.
Death Phase- total number of viable cells decline.
Phase of Prolonged Decline- some may survive and adapt to tolerate worsened conditions.
During which phase of growth are bacteria most susceptible to antibiotics
Exponential or Log Phase.
In which phase bacterial population rapidly multiply and cell numbers increase
Exponential or Log Phase.
All the different types of bacterial groups based on temperature preference
Psychrophiles: -5° to 15°C
Psychrotrophs: 20° to 30°C
Mesophiles: 25° to 45°C
Thermophiles: 45° to 70°C
Hyperthermophiles: 70° to 110°C
Proteins of thermophilesProteins of thermophiles resist denaturing. These proteins help thermophiles to survive in extreme temperatures.Human pathogens prefer which temperature rangeHuman pathogens prefer 35 to 40 COptimum pH for most bacteriaNear pH of 7. Most microbes are neutrophiles.The enzymes that deal with toxic oxygen-containing molecules areSuperoxide Dismutase and CatalaseHow does an aerobic organism protect itself from the action of Reactive Oxygen Species (ROS)?Producing enzymes Superoxide Dismutase and CatalaseGrowth factorsSome microbes cannot synthesize certain molecules. Amino acids, vitamins, purines, pyrimidines. Only grow if these growth factors are available. Picky microbes with strict nutritional requirements are termed fastidious.Chemotrophs, heterotrophs, autotrophsChemotrophs are microbes that gain energy from chemical compounds. Heterotrophs use organic carbon (glucose). Autotrophs use inorganic carbon (CO2).Aerobes, anaerobes, microaerophilesAerobes need oxygen. Produce own enzymes Superoxide Dismutase and Catalase. Anaerobes don't need oxygen. Don't produce Superoxide Dismutase and Catalase. Microaerophiles grows when small amounts of oxygen are available. Require low oxygen concentrations.Food preservationSalt and sugar used to preserve food. Refrigeration slows spoilage by limiting growth of otherwise fast growing mesophiles. Freezing preserves food not effective at killing microbes.MetabolismAll the chemical reactions in a living cell. Metabolism includes anabolic and catabolic reactions.Anabolism vs. CatabolismAnabolism involves building up molecules. Catabolism involves breaking down molecules.Potential energy vs. Kinetic energyPotential energy is stored energy Kinetic energy is energy in motionExergonic vs. EndergonicExergonic spontaneous release of energy Endergonic nonspontaneous energy is taken or absorbedOxidation vs. ReductionOxidation- when an atom or molecule loses an electron it is oxidized and the process is called oxidation. Reduction- when an atom or molecule gains an electron it is reduced, and the process is called reduction.ATPAdenosine triphosphate is the readily useable energy currency of cells.Oxidative phosphorylationthe production of ATP using energy derived from the redox reactions of an electron transport chain.Substrate level phosphorylationThe formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.Electron carriersMolecules that easily transfer electrons.EnzymesBiological catalysts that speed up conversion of substrate into product by lowering activation energy. Enzyme has active site to which substrates bind weakly. They have a narrow range of optimal conditions: temperature, pH, atmospheric conditions (O2, pressure), salt concentration.Structure of enzymesEnzymes are large proteins with complicated 3D space with an active site. Biological catalyst that speeds up chemical reactions but is never consumed by it.Function of enzymesEnzymes help speed up chemical reactions.Activity- activation energyThe energy needed to start a chemical reaction.Regulation- allosteric, competitive, non-competitiveAllosteric regulation, is enzyme activity controlled by end product binding to allosteric site. Competitive inhibitor binds to active site of enzyme. Non-competitive inhibitor binds to a different site than the active site.What is feedback inhibitionMeans of regulating the amount of product produced and often involves the use of allosteric enzymes.CofactorsAssist some enzymes. Inorganics: zinc, copper, other tolerable elements.What are electron carriers give 2 examplesNAD to NADH and FAD FADH2.CoenzymesOrganic cofactors. FAD, NAD, NADP. Derived from vitamins.GlycolysisConverts 1 glucose to 2 pyruvates yields net 2 ATP, 2 NADH. Does not need oxygen. May occur under aerobic or anaerobic conditions.Which central metabolic pathway generates most of the reducing powerKreb Cycle aka Tricarboxylic Acid.Electron Transport ChainAccepts electrons from NADH and FADH2 passes electrons down the chain. Energy released as electron passes. Forming about 28 ATP.ATP synthaseATP synthase large proteins that uses energy from hydrogen ions to bind ADP and a phosphate group together to produce ATP.Proton Motive forceA source of energy resulting from the separation of protons from hydroxyl ions across the cytoplasmic membrane, generating a membrane potential. Generated by electron transport chain.ChemiosmosisA process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.Aerobic vs. Anaerobic RespirationAerobic Respiration- with oxygen. Anaerobic- without oxygen (Lactic acid is byproduct)FermentationFermentation leads to the partial degradation of sugars in the absence of oxygen. A catabolic process that makes a limited amount of ATP from glucose without an electron transport chain and that produces a characteristic end product. Streptococcus pneumoniaelacks lack electron transport chain fermentation only optionCatabolism of proteins, lipids, and polysaccharidesIDK