NUTRITION AND GROWTH

EVERY LIVING ORGANISM MUST ACQUIRE 2 THINGS FROM ITS ENVIRONMENT IF IT IS TO GROW AND REPRODUCE: STRUCTURAL UNITS ENERGY SOURCE GROUPING ORGANISMS BASED ON NUTRITIONAL REQUIREMENTS: PHOTOHETEROTROPHS PHOTOAUTOTROPHS CHEMOHETEROTROPHS CHEMOAUTOTROPHS

EXAMPLES OF ORGANISMS FOUND IN EACH GROUP HOW DO ORGANISMS ACQUIRE THEIR NUTRITIONAL NEEDS? IT IS PROVIDED TO THEM IN A MEDIUM MEDIA - LAB OR ENVIRONMENT ALL MEDIA MUST HAVE THE FOLLOWING CHEMICAL ELEMENTS FOR GROWTH - CARBON (C) - NITROGEN (N) - WATER(H 2 O) -MINERALS(S,P,Ca,Mg,Na, etc.)

CARBON SOURCES: 1)CARBON DIOXIDE; 2)CARBOHYDRATES

CARBOHYDRATES ARE SELECTED BECAUSE: WATER SOLUBLE READILY ACCESSIBLE IN LAB AND NATURE USUALLY NON TOXIC IN DILUTE CONCENTRATION EASILY OXIDIZED AND REDUCED, LITTLE MODIFICATION NEEDED

SOME ORGANISMS CAN NOT USE CARBOHYDRATES AS A CARBON SOURCE. THEY WILL USE ALCOHOLS, AMINO ACIDS, FATS, ETC. NITROGEN SOURCES: 1) INORGANIC; 2) ORGANIC INORGANIC SOURCE : NITROGEN GAS(N 2 ) OR NH 4 CL/(NH 4 ) 2 SO 4 - NITROGEN FIXATION - SYMBIOTIC RELATIONSHIPS.

ORGANIC NITROGEN SOURCE

PROTEIN BUILDING BLOCKS OF PROTEINS ARE AMINO ACIDS

PRIMARY, SECONDARY,TERTIARY,AND QUATENARY SRUCTURE OF PROTEINS

MINERALS: MICRONUTRIENTS: ZN, CU, CO, MN, MO MACRONUTRIENTS: P, Mg, Ca, S, Na WATER - BIOLOGICAL SOLVENT THAT COMPOSES 80-85% OF THE WEIGHT OF CELLS.

SUBSTANCES WHICH MAY BE ADDED TO MEDIA BUT ARE NOT ALWAYS REQUIRED. -GROWTH FACTORS -BUFFERS -SOLIDIFYING AGENTS STERILIZATION OF MEDIA -AUTOCLAVING -FILTRATION a) NEGATIVE b) POSITIVE

CLASSIFICATION OF MEDIA SYNTHETIC OR CHEMICALLY DEFINED MEDIA A CHEMICAL FORMULA CAN BE WRITTEN FOR EVERY INGREDIENT COMPLEX MEDIA A CHEMICAL FORMULA CANNOT BE WRITTEN FOR EVERY INGREDIENT

OXYGEN GAS REQUIREMENTS OF MICROORGANISMS OBLIGATE AEROBES FACULTATIVES AEROTOLERANTS MICROAEROPHILICS OBLIGATE ANAEROBES

GROWTH DEFINITION: INCREASE IN MICROBIAL MASS OR INCREASE IN THE NUMBER OF CELLS GENERATION TIME: THE TIME IT TAKES AN ORGANISM TO REPRODUCE –BINARY FISSION –SHORTER FOR PROCARYOTES THAN EUCARYOTES –ENVIRONMENT EFFECTS GENERATION TIME

WE CAN DEMONSTRATE TYPICAL BACTERIAL GROWTH BY PREPARING A POPULATION GROWTH CURVE. THE BACTERIAL GROWTH CURVE –LAG PHASE –LOG OR EXPONENTIAL PHASE –STATIONARY PHASE –DEATH OR DECLINE PHASE