Bmsc 210 Mid1 p1

• 1. Understanding basic life processes
• • Microbes are excellent models for understandingcellular processes in unicellular and multicellularorganisms
• 2. Applying that knowledge to the benefit of humans
• • Microbes play important roles in medicine,agriculture, and industry

• 1Compartmentalization and metabolism
• 2Growth
• 3Evolution

• 1Motility
• 2Differentiation
• 3Communication

DNA produces RNA

RNA makes protein

generation of precursors of macromolecules(sugars, amino acids, fatty acids, etc.)

• – Oldest form of life
• – Largest mass of living material on Earth
• – Carry out major processes for biogeochemical cycles
• – Can live in places unsuitable for other organisms
• – Other life forms require microbes to survive

• -resources (nutrients)
• -environmental conditions (e.g., temp, pH, O2)

common ancestral cell from which all cellsdescended

4.6

3.8 ....3.9

evolution of oxygen-producing phototrophs (cyanobacteria)

• 2
• (anoxic:absence of oxygen)

one

• – nitrogen-fixing bacteria
• – cellulose(degrading microbes in the rumen)
• – regeneration of nutrients in soil and water

– diseases in plants and animals

• -process by which nitrogen gas (N2-) in the atmosphere is converted into ammonia (NH3) and then nitrates.
• -essentially for plants because nitrogen gas is not bioavailable
• 

• -microbes found in animals rumens
• -digest cellulose into fatty acids for nutrition
• -byproducts are methane (CH₄) and carbon dioxide(CO₂)
• 

-Food spoilage by microorganisms requiresspecialized preservation of many foods

• Microbial transformations (typically fermentations)yield
• – dairy products (e.g., cheeses, yogurt, buttermilk)
• – other food products (e.g., sauerkraut, pickles,leavened breads, beer)

• -Exploitation of microbes production of antibiotics, enzymes, and various chemicals
• -Genetic engineering of microbes to generate products of value to humans, such as insulin(biotechnology) Pathways

(1635–1703): the first to describe microbes– Illustrated the fruiting(reproductive) structures of molds

• (1632–1723): the first to describe bacteria
• – Further progress required development of more powerful microscopes- Small lense, high resolution, permanent focus

(1828–1898): founded the field of bacterial classification and discovered bacterial endospores

• -Discovered that living organisms discriminate between optical isomers
• – Discovered that alcoholic fermentation was a biologically mediated process (originally thought tobe purely chemical)
• – Disproved theory of spontaneous generation
• - Led to the development of methods for controlling the growth of microorganisms (aseptic technique)
• – Developed vaccines for anthrax, fowl cholera, and rabies

• – Demonstrated the link between microbes and infectious diseases
•      • Identified causative agents of anthrax and tuberculosis
• – Koch’s postulates
• – Developed techniques (solid media-cut potatoe) for obtaining pure cultures of microbes, some still in existence today
• – Awarded Nobel Prize for Physiology andMedicine in 1905

an entire colony grown from a single cell

• – Developed enrichment culture technique
•  • Microbes isolated from natural samples in ahighly selective fashion by manipulatingnutrient and incubation conditions
• – Example: nitrogen-fixing bacteria (Figure 1.21)

• and the Concept of Chemolithotrophy– Demonstrated that specific bacteria are linked to specific biogeochemical transformations (e.g., S & N cycles)– Proposed concept of chemolithotrophy
•  • Oxidation of inorganic compounds linked to energy conservation