Chapter 6 NUTRITION AND GROWTH

Nutritional Requirements EVERY LIVING ORGANISM MUST ACQUIRE TWO THINGS FROM ITS ENVIRONMENT TO GROW AND REPRODUCE: STRUCTURAL UNITS ENERGY SOURCE GROUPING ORGANISMS BASED ON NUTRITIONAL REQUIREMENTS (examples): PHOTOHETEROTROPHS PHOTOAUTOTROPHS CHEMOHETEROTROPHS CHEMOAUTOTROPHS

How Do Organisms Acquire Their Nutritional Needs? MEDIA - LAB OR ENVIRONMENT ALL MEDIA MUST HAVE THE FOLLOWING CHEMICAL ELEMENTS FOR GROWTH - CARBOBN (C) - NITROGEN (N) - WATER (H2O) - MINERALS (S,P,CA,MG,NA, ETC.)

Carbon Sources oCARBON DIOXIDE oCARBOHYDRATES 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

Carbon Sources (Continued) 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.

Nutritional Sources INORGANIC –NITROGEN GAS(N 2 ) OR NH 4 CL/(NH 4 ) 2 SO 4 - NITROGEN FIXATION - SYMBIOTIC RELATIONSHIPS ORGANIC

Nutritional Sources ORGANIC N SOURCE –PROTEIN - BUILDING BLOCKS ARE AMINO ACIDS. PRIMARY, SECONDARY AND TERTIARY STRUCTURES OF PROTIEINS –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.

Other Substances in Media SUBSTANCES WHICH MAY BE ADDED TO MEDIA BUT ARE NOT ALWAYS REQUIRED. GROWTH FACTORS BUFFERS SOLIDIFYING AGENTSSTERILIZATION OF MEDIA AUTOCALVING 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 PROKARYOTES THAN EUKARYOTE –ENVIRONMENT EFFECTS GENERATION TIME

Binary Fission

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

Growth Curve