BACTERIA

• MacConkey agar


  Dye present that is inhibitory to Gram-positive bacteria
• Freeze drying


  The process in which a pure culture of microbes is placed in a suspending liquid and quick-frozen without water (sublimation) at temperatures ranging from -54C to -95C
• Neutrophiles


  Microorganisms that grow between pH 5-9
• Microbial Dry Weight Measurements


  The kind of measurement which is the only way to determine growth of filamentous bacteria
• Fontana's Silver Stain


  The kind of stain that should be used to verify if the bacterial growth is really Leptospira under a dark-field microscope
• Fluid Mosaic


  This refers to the effect which may be because of stiffening of the lipids of the membrane leading to decreased efficiency of transport proteins embedded in the membrane (related to bacterial growth curve)
• Stanley B. Prusiner


  Discovered Prion
• Stationary Phase


  The phase of microbial growth in which sporulation occurs in endospore forming bacteria
• Lophotrichous


  The arrangement of the flagella in this bacterium
• Gaspak


  The method of choice for preparing anaerobic jars
• Reducing substances for anaerobic media

  • Thioglycollate broth
  • Cooked meat broth (CMB)
• Methods of Anaerobiosis


  • Production of a vacuum
  • Displacement of oxygen by other gases
  • Absorption of oxygen by chemical or biological methods
• Methods of bacterial preservation

  • Refrigeration
  • Deep freezing
• Cryophiles


  Cold-loving bacteria
• Mesophiles


  Bacteria with moderate temperature requirement
• Thermophiles


  Heat-loving bacteria
• Hyperthermophiles


  Bacteria that thrive in extremely high temperatures
• The number of bacteria in a given sample is usually too great to be counted directly
• Counting bacterial colonies


  1. Sample is serially diluted

  2. Plated out on agar surface

  3. Single isolated bacteria form visible isolated colonies

  4. Number of colonies used as measure of viable cells in known dilution
• In using direct microscopic counts, dead cells cannot be distinguished from living ones
• In the lag phase, bacterial population is nearly uniform in terms of their metabolic activities, chemical composition of cell and other physiological characteristics
• Acid-fast bacteria contain mycolic acids in their cell wall which combines with the counterstain, safranin
• If the flagellum is cut off it will regenerate from the base until it reaches a maximum length
• Most pathogenic bacteria are chemolithotrophs
• Gram-negative bacteria have thin peptidoglycan layer and an outer membrane while Gram-positive bacteria have uniformly dense cell wall consisting primarily of peptidoglycan
• The cell membrane is the cellular structure that is important in classifying a bacterial species as Gram-positive or Gram-negative
• Phospholipid Bilayer


  Outer membrane?
• Peptidoglycan


  Cell wall
• A type of bacteria that derive energy from the chemical bonds in molecules to power metabolic processes
• Two principal gases that affect the growth of microbes

  • Oxygen
  • Carbon dioxide
• Pentose Phosphate Pathway


  A pathway that is crucial for the production of ribose-5-phosphate, a precursor for the synthesis of nucleotides
• Entner-Doudoroff Pathway


  A pathway that is an alternative to glycolysis and is often linked to specific environmental conditions and metabolic requirements such as with limited oxygen availability
• Active Diffusion


  Transport system that move substances against a concentration or electrochemical gradient by expending energy through carrier proteins
• Exoenzymes


  Synthesized within the cytoplasm of the cell and secreted into extracellular environment and breakdown complex molecules into simpler forms that can be absorbed and utilized by the cell
• Passive (simple) diffusion


  A process in which molecules from a region of higher concentration moves to one of lower concentration
• Facilitated diffusion


  Mediated by specific membrane proteins collectively known as permeases with no energy input
• Categories of essential nutrients

  • Micronutrients
  • Macronutrients
• Four types of bacteria based on oxygen requirements

  • Aerobes
  • Anaerobes
  • Facultative anaerobes
  • Microaerophiles
• Metabolism


  The sum of the biochemical reactions required for energy generation and the use of energy to synthesize cell material from small molecules in the environment
• Nutrition


  The process by which nutrients are acquired from the environment