Lecture 2 Notes (Part 1) Flashcards
What are bacteria?
They are microscopic unicellular living organisms
(most > 0.5- < 5.0um) with no organelles
Why cant you catch a virus with a standard filter?
Viruses are too small and they will fall right through
What does bacteria have a complete set of?
RNA
- they can reproduce themselves
What are viruses?
They are microorganisms ( < 0.2um) with no capacity to generate their own energy
What do viruses lack?
A complete set of RNA
Mimivirus
Isolated from bacteria and large virus identified through typhus via rickettsia toxin
What are the 2 hypothesis’s that emerged from a virus?
- Parasites losing ability to live freely
2. Gained genes to live as a virus
Where can bacteria and viruses be found?
EVERYWHERE
What do bacteria have a great ability to do?
Gain energy
What do the building blocks of life form a variety of in the environment? (7)
- Soil
- Freshwater
- Marine
- Hydrothermal vents
- Hot springs
- Volcanoes
- Plants/fungus
What are the 3 building blocks of life?
- Carbon
- Nitrogen
- Phosphorus
What does bacteria have the ability to do since they can evolve new physiologies?
Ability to colonize very different, very harsh environments
What are the 6 characteristics of bacteria?
- Self-feeding or nutrition
- Self-replicating
- Differentiation
- Chemical signalling
- Movement
- Evolution ** MOST IMPORTANT**
Sporulation
Is the formation of nearly dormant forms of bacteria
Quorum sensing
Is a system of stimuli and response correlated to population density
How do autotrophic organisms derive their energy? (2)
- Light (photoautotrophs)
2. Chemical oxidation (chemoautotrophs)
Why do autotrophic organisms derive carbon?
For synthesis of organic molecules and polymer from CO2 or carbonate
How do heterotrophic organisms derive their energy? Give 4 examples
From the oxidation of organic molecules
- Glucose
- Acetate
- Cellulose
- Lipids
What type are most pathogenic bacteria?
heterotrophic
- require some form of carbon
What was Liebigs the founder of?
Agriculture chemistry by his research on plant and animal nutrition
- research on understanding chemical factors that influence the growth of plants for agriculture purposes
What are field of crops limited by?
Nutrients
What do plants assimilate N as? (2)
- NH4
2. NO3
What lead to the use of chemical fertilizer in agriculture?
Discovery of Haber-Bosch process of chemical reduction of N2 to NH3
What was Liebig wrong about?
He thought that plants assimilated N via gaseous ammonia in a similar fashion that they assimilate Co2 via photosynthesis
What is iron a critical element for?
Cellular respiratory chain
What is growth limited by?
By the lowest concentration for the nutrients that is available for consumption
What have bacteria and cyanobacteria evolved?
Specific iron carries called siderophores, solubilization iron for transport
How much iron is stored in the human body?
5g
Why is free iron kept very low in humans?
Because if its toxicity
Siderophores
A molecule that binds and transports iron in microorganisms
Enterobactin
Is a high affinity siderophore that acquires iron for microbial systems
What are 2 examples of enterobactin?
- Salmonella
2. E. coli
What is Martins experiment?
Determines how iron is a limiting factor of phytoplankton
What is growth controlled by?
By the scarcest resource
- limiting factor
What are the 2 principles constraining Leibig’s Law?
- This law is strictly applicable only under stead state conditions
- Limiting factor for an organism may change according to the interaction of the other environmental variables
Steady state
Is an unchanging conditional, system or physical process that remains the same even after transformation or change
What did Leibig’s law not consider?
The fact that the success of an organism is living in a environment may not only depend on the availability of nutrient but also on the tolerance of a given organism to variation of factors
- eg) temp, pH, salinity, oxygen, pressure
Who came up with the concept of the limiting effect of max and min?
Vernon Shelford
How do eurytypic organisms grow?
In a wide range of specific conditions
How do stenotypic organisms grow?
In a narrow range of specific conditions
What is E.coli an example of?
Stenotypic
What is S. aureus an example of?
Eurytypic
Halotolerent
Is the adaptation of living organisms to conditions of high salinity
What is the most important factor for life existence?
Water
What can prokaryotes do to adapt with water?
The develop molecular adaptations to support low availability of water
What did Kind and Schnell (1996) study?
The effect of water on methane oxidation in forest soil
