Microbiology Chapter 5 Microbial Metabolism What is Metabolism

Microbiology Chapter 5 Microbial Metabolism

What is Metabolism? • How an organism uses energy and matter. • All of the chemical reactions that take place in organisms. • Two Types: • Anabolism-to build up. • Catabolism-to break down.

Four Basic Types of Metabolic Organisms: Photoautotrophs Photoheterotrophs Chemoautotrophs Chemoheterotrophs

Photoautotrophs • Capture light energy to acquire energy through the process of photosynthesis (Carbon dioxide (CO 2) in atmosphere). • Examples: Plants, phytoplankton,

Photoheterotrophs • Depend upon light for their source of energy and mostly organic compounds from other organisms (not CO 2) for their source of carbon. • Ex. Heliobacteria

Chemoautotrophs • Use inorganic energy sources to synthesize organic compounds from carbon dioxide (CO 2) • Examples: Nitrosomonas, Methanogens

Chemoheterotrophs • Use inorganic energy sources to synthesize organic compounds from sources other than CO 2. • Their carbon source is derived from other organisms in the forms of sulfur, carbohydrates, lipids and proteins. • Examples: Animals, Fungi, Bacterial decomposers

Photosynthesis • Photosynthesis is the process used by photoautotrophs to convert energy into matter. 6 H 2 O + 6 CO 2 C 6 H 12 O 6 + 6 O 2 2 Parts: Light dependent and light independent (Calvin cycle) reactions.

Cellular Respiration (Aerobic) • Cellular Respiration is the process chemoheterotrophs use to convert organic compounds into energy. • 6 O 2 + C 6 H 12 O 6 6 H 2 O + 6 CO 2 • 3 Steps: Glycolysis, Kreb’s cycle and Electron Transport Chain (ETC).

Cellular Respiration (Anaerobic) • Anaerobic cellular respiration is the process chemoheterotrophs use when no Oxygen is present. • 2 Steps: Glycolysis & Fermentation • Two Types of Fermentation: • Lactic Acid & Alcoholic • Obligate Anaerobes-no Oxygen may be present or they die. • Facultative Anaerobes-can survive with or without Oxygen.

Nitrogen Fixation • Some Bacteria have the ability to take Nitrogen (N 2) out of the atmosphere and into the soil. • Symbiotic relationship with a type of plants called legumes (beans)

Nitrification • Some soil Bacteria have the ability to break down Nitrogenous waste products (Urea, ammonia).

Denitrification • Some Bacteria take the products of Nitrification and convert back into Nitrogen gas in the atmosphere completing the Nitrogen Cycle.