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Questions and Answers
What is the process called by which carbon dioxide is transformed into an organic form?
Which organism is primarily responsible for the process of nitrogen fixation in the environment?
What is produced when nitrogenase combines atmospheric nitrogen with hydrogen?
What is the main role of nitrifying bacteria in the nitrogen cycle?
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What is denitrification in the context of the nitrogen cycle?
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Which type of extremophile thrives at temperatures of 55-65 °C?
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What is the upper growth temperature that thermophiles can withstand?
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Which of the following organisms are classified as osmophiles?
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What temperature range is optimal for psychrophiles to grow?
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What environmental condition do halophiles thrive in?
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Which of the following is a characteristic of acidophiles?
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What role do osmoprotectants play in osmophiles?
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Which extremophile would likely be found in alkaline environments?
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What type of environment do methanogens require to produce methane?
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Which of the following is an example of a methanogen?
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How do methylotrophs primarily obtain their carbon and energy?
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What is a key characteristic of dissociative processes in microbial metabolism?
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Which of the following classifications of microorganisms does NOT require pre-formed organic matter?
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What distinguishes photoheterotrophs from photoautotrophs?
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Which classification of microorganisms utilizes light as an energy source and requires CO2 for carbon?
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What type of microorganism can use organic matter as a source of both energy and carbon?
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What are the two complementary roles of microorganisms in ecosystems?
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Which type of nutrient is particularly crucial for primary production in aquatic ecosystems?
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What distinguishes terrestrial ecosystems from aquatic ecosystems?
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In assessing microbial diversity, what is primarily being evaluated?
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What is a biogeochemical cycle?
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Which microbial process is part of controlling global biogeochemical cycling?
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Which of the following does cyanobacteria primarily utilize for energy?
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Which of the following cycles is classified as a sedimentary biogeochemical cycle?
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Study Notes
Extremophiles
- Organisms survive, grow and reproduce in extreme or unusual environments
- Examples include Thermophiles, Psychrophiles, Osmophiles, Halophiles, Alkalophiles, Acidophiles, Methanogens, and Methylotrophs.
Thermophiles (Heat-Loving)
- Capable of growth in temperatures between 55-65°C.
- Minimum growth temperature: 45°C.
- Maximum growth temperature: 110°C.
- Contain heat-stable enzymes.
- Used in biotechnology.
- Examples: Thermus aquaticus and Thermococcus littoralis, which are sources of the enzyme DNA polymerase used in PCR.
Psychrophiles (Cold-Loving)
- Mostly bacteria or archaea
- Also called Cryophiles.
- Found in Antarctic oceans and deep ocean.
- Can grow and reproduce in temperatures ranging from 4°C to +15°C.
- Contain cold-active enzymes and special proteins or cryoprotectants called antifreeze proteins.
- Examples: Arthrobacter sp. and Psychrobacter sp.
Osmophiles (Sugar-Loving Organisms)
- Grow in high sugar concentrations.
- Protect themselves from high osmotic pressure using osmoprotectants like alcohols and amino acids.
- Important because they cause spoilage in the sugar and sweet goods industry.
- Examples: Aspergillus, Saccharomyces, Enterobacter aerogenes, and Micrococcus.
Halophiles (Salt-Loving Organisms)
- Live in high salt concentrations.
- Most are aerobic and heterotrophic.
- Some are anaerobic and photosynthetic.
- Examples: Halobacterium and Halococcus.
Alkalophiles
- Grow at pH 9 and above.
- Isolated from alkaline environments.
- Cell surface plays a crucial role in maintaining intracellular pH between 7 and 8.5.
- Used in biological detergents and enzyme production.
- Examples: Bacillus okhensis and Alkalibacterium sp.
Acidophiles
- Grow at pH 3 or below.
- Capable of pumping hydrogen ions out of their cells.
- Internal pH is about 6.5, while external pH is 2.5 or less.
- Used in enzyme production.
Methanogens (Methane-Producing Bacteria)
- Belong to the Archaea group of prokaryotes.
- Produce methane gas.
- Require anaerobic conditions.
- Many require warm conditions to function optimally.
- Used as sources of biogas, which is a renewable energy source.
- Examples: Methanobacterium and Methanococcus.
Methylotrophs (Methane-Degrading Organisms)
- Aerobic organisms that can use reduced one-carbon compounds like methanol or methane as a carbon and energy source.
- Can also grow on other organic molecules, including organic acids, ethanol, and sugars.
- Examples: Methylosinus sp. and Methylococcus capsulatus (used to degrade methane and other pollutants).
Assimilative Processes
- Bring needed elements into the cell and incorporate them into cell protoplasm.
Dissimilative Processes
- Don't incorporate elements into the cell but instead use energy gained in the process to form ATP.
Autotrophs
- Derive energy from either light absorption (photoautotrophs) or oxidation of inorganic molecules (chemoautotrophs).
Heterotrophs
- Require preformed organic matter.
Photosynthetic bacteria (photoheterotrophs)
- Require preformed organic matter as reducing agents, but generate ATP from light energy absorption.
Classification of Organisms Based on Energy Source
- Photoautotroph: Light energy, CO2 for carbon source (e.g., bacteria, plants).
- Chemoautotroph: Inorganic compounds for energy, CO2 for carbon source (e.g., bacteria).
- Photoheterotroph: Light energy, CO2 and organic matter for carbon source (e.g., bacteria).
- Heterotroph: Organic matter for energy and carbon source (e.g., bacteria, fungi, animals).
Ecological Roles of Microorganisms
- Two key roles in ecosystems:
- Synthesis of new organic matter from CO2 and other inorganic compounds during primary production.
- Decomposition of accumulated organic matter.
Aquatic Ecosystems
- Water-based ecosystems.
- Main types: marine and freshwater.
- Primary production governed by the supply of essential nutrients, particularly nitrogen.
Terrestrial Ecosystems
- Differ from aquatic ecosystems by the lower availability of water.
- Water is a key limiting factor.
Microbial Community Diversity
- Assessing microbial diversity answers the question: "What microbes are present and what are their characteristics?"
Microbial Community Abundance
- Assessing microbial abundance answers the question: "How many microbes are present in terms of numbers and/or biomass?"
Microbial Community Activity
- Assessing microbial activity answers the question. "What are the microbes doing, and how are they impacting the abiotic and biotic environment?"
Bioeochemical Cycles or “Nutrient Cycles"
- Cycles through which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another.
- Types:
- Atmospheric (Carbon Cycle, Nitrogen Cycle)
- Sedimentary (Phosphorus Cycle, Sulfur Cycle)
Microbial Role in Bioeochemical Cycling
- Microbes control global biogeochemical cycling through key metabolic processes, including:
- Nitrogen fixation
- Carbon fixation
- Phosphorus metabolism
- Sulfur metabolism
Carbon Cycle
- Cyanobacteria (blue-green bacteria, blue-green algae) obtain energy through photosynthesis.
- Carbon fixation: CO2 absorbed from the atmosphere and transformed into a usable organic form.
Nitrogen Cycle
- Nitrogen is essential for all forms of life for synthesizing basic building blocks (DNA, RNA, amino acids).
- Nitrogen fixation: Conversion of unusable atmospheric nitrogen (N2) into forms that living organisms can use.
- Mostly done by nitrogen-fixing bacteria containing the enzyme nitrogenase, which combines N2 with hydrogen to produce ammonia (NH3).
- Nitrifying bacteria convert ammonia (NH3) to nitrate (NO3-) which is the most oxidized form of soil nitrogen.
- Denitrifying bacteria carry out denitrification, converting nitrogen oxides back to nitrogen gas (N2) or nitrous oxide (N2O).
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Description
This quiz explores extremophiles, organisms that thrive in extreme environments such as heat, cold, and high sugar concentrations. It covers different types including thermophiles, psychrophiles, and osmophiles, detailing their characteristics and applications in biotechnology. Test your knowledge about these fascinating organisms!
