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UNIVERSITY OF THE SCIENCES IN PHILADELPHIA / BS / BS 243 / What are the 3 stages of calvin cycle?

What are the 3 stages of calvin cycle?

What are the 3 stages of calvin cycle?


10 / 7 ch.20+21

  • Ecosystem - the dynamic complex of sum total of all organisms(plant, animal and microbial communities) and the abiotic factors in a particular environment all of which interact as a functional unit
  • Habitat - potion of an ecosystem best suited (with respect to nutrients + conditions) for one or more population to reside
  • An ecosystem contains many different habitats
  • Population - a group of organisms of the same species that reside in the same place at the same time
  • Community - 2 or more different populations living in association
  • Species richness and abundance - diversity of microbial species in a ecosystem is express in 2 ways
  • Species richness - total number of different species present
  • Species abundance - proportion of each species in an ecosystem
  • Microbial species richness and abundance are functions of the kinds and amounts of nutrients available in a given habitat
  • Ecosystem service: biogeochemistry and nutrient cycles
  • Guilds - metabolically sumillar microbial populations that exploit the same resources in a similar way
  • Niche - habitat shared by a guild, supplies nutrients as well as conditions for growth
  • Biogeochemistry - study of biologically mediated chemical transformations
  • Biogeochemical cycle defends the transformations of a key element of biological or chemical agents
  • Typically proceed by redox reactions
  • Microbes play a critical role in energy transformations and biogeochemical processes that result in the recycling of elements to living systems
  • Biogeochemical cycling of sulfur and carbon

  • Environments and microenvironments - realized niche or prime niche - niche in which an organism is most successful
  • For each organism, there exists at least one niche in which that organism is most successful
  • The density of a population depends on how closely it niche resembles a realized niche
  • Fundamental niche - the full range of environmental conditions under which an organism can exist
  • Microenvironment - tiny local environment experienced by microbes and can change rapidly
  • Enrichment culture and isolation - resources and nutrients most closely mimic those of the natural habitat of the organism of interest, growth medium well select for organism of interest and select against all else, thus isolating organism of interest in pure culture

    “Feast or famine” existence

  • Resources in natural environments are highly variable
  • Conditions in a microenvironment are subject to rapid change, both spatially and temporally
  • Production of storage polymers - common
  • Extended periods of exponential growth - rare
  • Growth rates in nature are usually well below that
  • Microbes in nature grow in mixed populations
  • Competition and cooperation occurs between microbes in natural systems
  • Cooperation: syntrophy: transformations carried out by different microbes working together
  • Interspecies M2 transfer:
  • M2 production by the “syntroph”
  • M2 consumption by “consumer”
  • Cooperation: complementary metabolism
  • Nutrification - discovered by Winogradsky
  • The two partners live in close association


                    Nitrifying bacteria                nitrite oxidizing

                    Eg. nitrosomonas                bacteria

                    Arehasa                        eg. nitrobacter

                    Eg. nitrosopumilus

    Biofilms and microbial mats

  • Surfaces are important microbial habitats
  • Nutrients absorb to surfaces
  • Bacteria form biofilms for various reasons:
  • Self defense
  • Allows cells to remain in a favorable niche
  • Allows bacterial cells to live in close association with one another
  • Microbial mats are very thick biofilms
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