2. Microbiology 101 Flashcards
Types of organic pollutant degradation (2)
- abiotic
- biological mechanisms
Types of abiotic mechanisms (3 + examples)
- photochemical
- chemical (e.g. oxidation, reduction, …)
- mechanical (e.g. wind, water, mixing, dilution)
Types of biological mechanisms done by plants and animals (2)
- direct consumption
- indirect degradation via compounds secreted by organisms, associated with microbes biodegrade contaminants
How do microorganisms degrade pollutants? (3)
- diverse metabolism
- mineralization
- modification or transformation (product may be more or less of a pollution problem)
What is mineralization?
Conversion of organic compounds to CO2
What are microbes? (6)
Microsocopic:
- plants
- animals (including protozoa)
- bacteria
- fungi
- archaea
- viruses
Are visible bacteria still microbes?
Yes e.g. cyanobacteria
Main morphologies of prokaryotes (shapes) (2)
- rods / bacili = rectangular boxes
- cocci = spheres
What is hegemony?
Leadership, predominant influence, or domination of, esp. as exercised by one nation over others
Microbial hegemony? (3 points)
- domination = 50% of the global biomass is microbial
- predominant influence = global biogeochemical cycling
- leadership, supremacy = extraordinary metabolic capacity
Why is microbiological evolution important to biodegradation? (6 points)
- microbes have been around for 3-4 billion years
- over that time they have become exposed to every single imaginable organic compound and environment
- they evolved complex processes
- any niche or source of energy and carbon has been exploited meaning that they can live almost anywhere on the planet
- but most microbial species have never been cultured (99%)!
- we do not know much about their metabolic pathway, etc
Can bacteria and archaea be grown in culture?
The vast majority cannot be grown in culture.
Some may be viable-but-not-culturable (VBNC)
If they are not culturable, how do we know they exist? (3)
- Microscopy: direct microscopic counts can exceed viable counts by several orders of magnitude
- Respiration tests
- Molecular biology: 16S rRNA sequences, the molecular clock, position on tree of life
What are Haeckel and Whittaker’s trees of life based on? And why doesn’t that work well for bacteria, prokaryotes?
- Morphology (shape)
- because most are all rods or spheres
What is the tree of life based off of?
The comparison of 16S rRNA sequences (phylogeny)
Where is there the greatest diversity according to the tree of life?
The microbial world
What are the 3 forms of life?
- bacteria
- archaea
- eukaryotes
Bacteria (3 points)
- include pathogens
- but the majority of species have never been characterized
- are found in every niche on the planet
Archaea (2 points)
- previously thought to be limited to extreme environments, like anaerobic sediments and hot springs
- although they do dominate some of these niches, they are found everywhere
How many branches did the last common ancestor give rise to?
2 branches: Bacteria & Archaea/Eucarya
- Archaea and Eucarya split later
what is anaerobic?
without oxygen
What is the central dogma of life?
Genetic information flows from DNA, to RNA, to protein.
Relating the central dogma to evolution of metabolic capacities in microbes
genetics → physiology → ecological niche → genetics
What is the ecological niche the site of? (2)
- competition / predation
- change in conditions (physical and environmental conditions)
So these factors are part of the selective pressure that stimulates the evolution of metabolic capacities in microbes
What does it mean for biodegradation that microbes have been around since the atmosphere was harsher? (3)
- They have evolved many different and complex metabolic strategies
- So, they can be used to degrade many types of pollutants that are toxic to us
- This also means that the probability that we find a species that can bioremediate a particular problem is high
How can we find what microbes would be useful for specific bioremediation?
Culture based and/or molecular based methods
Where do we look for pollution biodegraders? (2 places and why)
Soil and water in contaminated sites
This is because biodegraders should be enriched and selected for in these environments
