Lecture 2 Whyte Flashcards
What are organic pollutants?
They contain carbon, ex: DDT and oil
Name some abiotic degradation mechanisms:
- photochemical (sunlight very good at degrading hydrocarbons)
- chemical (oxidation/reduction)
- mechanical (waves, storms, winds) - wind, water, mixing, dilution
What are microorganisms the most important in pollutant degradation?
Because they are responsible for 90-95% of the biodegradation
What does mineralization mean?
Converting organic compounds to CO2
Modification or transformation:
product may be more or less of a pollution problem
Microbiology is the study of __________
bacteria
Microscopic:
- plant and animals (including protozoa)
- bacteria
- fungi
- archaea
- viruses and prions
Thiomargarita namibiensis:
- some type of sulfur metabolism
- anaerobic uses nitrate as an electron acceptor
Leadership, predominant influence or domination of esp. as exercised by one nation over others :
Hegemony
T or F: Over 50% of the global biomass is ____________
microbial
Leadership, supremacy of microbial:
extraordinary metabolic capacity!
How old is the earth?
4.5 billion years old
Microbes have been around for about ______, over that time they have been exposed ti every imaginable organic compound and environment
3-4 billion years
T or F: Microorganisms have a complex metabolic process that has evolved over time
T
T or F: 99% of microbial species have never been cultured
T
4.5 billion years ago theres was no free ____ in the atmosphere
O2
Oxygen occured in the atmosphere when cyanobacteria came up with ____________
oxygenic photosynthesis
T or F: eukaryotic cells have organelles and nucleus
T
Bacteria have been on Earth for ____ billion years
3.5
Cyanobacteria are capable of:
- photosynthesis
- nitrogen fixation
Stromatolites =
cyanobacteria-like microfossils
In 1g of soil you can find ________ cells and _______ species
10^8-10^9
10,000+
The vast majority of bacteria and archaea cannot be grown in culture, some may be viable but ________________
not culturable
If some bacteria are not culturable, how do we know that they exist at all?
1) Microscopy: direct microscopic counts can exceed viable counts by several orders of magnitude
2) Respiration tests
3) Molecular biology
- 16srRNA sequences, the molecular clock, position on tree of life
What are the top 3 habitats for microorganisms culturability?
- activated sludge
- soil
- sediments
- freshwater
Prokaryotic cells do not have a _________
nucleus
Name some common prokaryotic morphologies:
- coccus
- bacillus
- spirillum
- stalked bacteria
The lecture that changed biology was called the __________ and was given by _____________
central dogma of life
Francis Crick
Explain the central dogma of life:
Once information has got into a protein, it can’t get out again
(DNA - RNA - Protein)
There are 3 life forms on Earth that are all related to a lost common ancestor:
- bacteria
- archaea
- eukaryotes
Based on 16s rRNA, prokaryotic world is the most __________
diverse
T or F: we think that eukaryotes evolved from the fusion of a bacterial cell with and archaeal cell approx 2 billion years ago
T
Based on the comparison of 16S rRNA sequences, it is possible to study the phylogenetic relationship between all cells. The picture emerging from these studies suggests that the greatest diversity in the living world is within the ______________
microbial world
We have archaea in our intestines that act as _____________ (produce methane)
methanogens
The ___________ include the well-known species, including pathogens humans are most concerned about, but the majority of species have never been characterized and are found in every niche on the planet
bacteria
The _______ are organisms previously thought to be limited to extreme environments such as anaerobic environments, hot springs, and others. While Archaea dominate some of these niches, they are ubiquitous. Archaea have some unique physiological properties
Archaea
Evolution of metabolic capabilities in bacteria:
genetics, physiology = ecological niche, genetics
Ecological niche is the site of _________ and ________, these factors are part of the selective pressure that stimulates the evolution of metabolic capacities in microbes
competition
change in conditions
The probability that we will find a species or consortia of species that can bioremediate a particular pollution problems is _____
high
May have to use _______ and/or molecular methods to find microbes that would be useful for bioremediation
culture-based
Where to look for pollution degraders?
Soil and water in contaminated sites is a great place to start, biodegraders should be enriched and selected for these environments
What are 3 key properties of prokaryotes:
- small size (1-2 um), high S/V ratio, favours chemistry
- rigid cell wall (requires transport extracellular enzymes)
- metabolic diversity (alternate energy sources, light, organics, inorganics, alternate oxidants (O2, metals, CO2, etc)
What are 3 key properties of eukaryotes:
- larger size cells (10/25um), complex structures multicells/tissues
- flexible cell walls (phagocytosis)
- metabolic specialisation (O2 respiration, organic C as fuel)
In the microbial world, growth is essentially the multiplication of cells by the successive division of mother cells into 2 ___________
daughter cells
Metabolism can be divided in 2 sets of reactions:
catabolic and anabolic
Microbes obtain energy by a complex set of _______________
redox reactions
________ is the removal of electrons from an atom or molecule
oxidation
___________ is the addition of electrons
reduction
Oxidation reduction reactions can result in the release of free energy which is captured in the form of _______________
energy rich chemical bonds
If glucose is the main nutrient for a bacterium, it will be first transported across the membrane, then it will be oxidized to _____
CO2
The mineralization process can be divided in three steos:
Step 1: Glycolysis, the breaking of glucose (6C) into 2 molecules of pyruvate (3C)
Step 2: The complete combustion of pyruvate to CO2 through a cyclic set of reactions: the tricarboxylic acids cycle (Krebs cycle), during this cycle, the pyruvate will be decarboxylated leasing to the production of CO2
Step 3: Some of these reactions will lead to the reduction of coenzymes (NADH, FADH) that will be further oxidized in the respiratory chain (electron transport system) in a process known as oxidative phosphorylation which produces the proton motive force (PMF)
What is Atrazine:
A pesticide that was created during the revolution of food production to increase productivity, microorganisms had never seen these molecules before - they didn’t have the time to evolve a chemical pathway to get rid of them
Benzene is an hydrocarbon found in ___________
gasoline
Toluene and xylene can be used in:
household products
Oxygen is the terminal electron acceptor in ______________ respiration
aerobic
What is Aerobic respiration:
- It uses oxygen as terminal electron acceptor
- Reducing power (NADH etc) generated by oxidation of energy source
- Electrons are transferred to the ETC, then to the terminal electron acceptor (O2 into H2O)
- Results in a proton gradient (H+) outside the cell membrane
- H+ gradient fuels processes like ATP synthase pump to create ATP
**The overall process is called oxidative phosphorylation
