MICROPARA

• PLASMOLYSIS = Sudden exposure to hypertonic solutions may cause osmotic withdrawal of water and shrinkage of protoplasm. This occurs more readily in gram negative than in gram positive bacteria.
• Acidophilic - bacteria grow in acidic pH.
• Alkaliphiles - Some bacteria grow in alkaline
• Most bacteria have an average pH requirement of 7.2-7.6 which matches with pH in human body environment.
• Physiology – the scientific study of functions and mechanisms in a living system
• Colony – group of cells large enough to be seen without a microscope
• AUTOTROPHS = Bacteria which can synthesize their own food.
• HETEROTROPHS = bacteria which cannot synthesize their own food.
• Parasitic – They derive their food from living organisms.
• Saprophytic – They feed on dead and

  decaying organic matter.
• Symbiotic – They live in symbiotic

  association with other organisms.
• chemosynthesis - uses chemicals such as CH4 or H2S and along with O2 to produce CO2 and energy
• Chemolithotrophs - use inorganic chemicals
• Chemoorganotrophs - use organic chemicals
• AUTOTROPHS - use CO2 as their energy source
• PHOTOAUTOTROPH - use light energy and CO2
• PHOTOHETEROTROPH - use light and organic compounds
• CHEMOAUTOTROPH - use chemicals are energy source and CO2 as carbon source
• HETEROTROPHS - use organic compounds as their carbon source
• CHEMOHETEROTROPHS - use chemicals as energy source and organic compound
• Hydrogen and oxygen = supplied from water added to the culture medium.
• Carbon = supplied by carbohydrates. Bacteria also get energy in the form of ATP from carbohydrate breakdown.
• Nitrogen = it is a major component of proteins and nucleic acids. It is obtained from mainly ammonia, usually in the form of ammonium salts. Ammonium salts are obtained from environment or from deamination of amino acids.
• Sulphur = It is a part of proteins and coenzymes. Sulphur is obtained from sulphates. Many bacteria reduce

  these sulphates to hydrogen sulphide (H2S).
• Phosphorus = it is required for nucleic acids, ATP, coenzymes etc.
• Potassium, calcium, magnesium, iron, copper, cobalt, manganese, molybdenum and zinc - these elements are required in trace amounts and are provided from various food sources.
• ORGANIC GROWTH FACTORS Required by bacteria for their growth and maintenance. They are called BACTERIAL VITAMINS.
• 80% of bacterial cell consists of water.
• Spores are particularly resistant to dessication and may survive in

  the dry state for several decades.
• FREEZE DRYING OR LYOPHILIZATION: Drying in vacuum in cold. It is a method of preservation of bacteria, viruses and many labile biological materials.
• AEROBE = bacteria which require oxygen for growth.
• ANAEROBES = bacteria which do not require oxygen for growth.
• OBLIGATE AEROBE = bacteria which grow only in the presence of

  oxygen.
• FACULTATIVE ANAEROBE = bacteria which are aerobes but can grow

  with lack of oxygen or in absence of oxygen.
• MICROAEROPHILIC = bacteria which grow with trace amount of oxygen.
• OBLIGATE ANAEROBES = bacteria which strictly grow in the absence of oxygen. They may die on exposure to oxygen.
• AEROTOLERANT ANAEROBES = anaerobes which do not require oxygen but tolerate the presence of oxygen.
• 5-10% CO2 is supplied for them in culture.
• Capnophilic = requiring excess amount of CO2
• MINIMUM GROWTH TEMPERATURE = The lowest temperature at which the organism can survive and replicate