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Questions and Answers
Which temperature classification prefers temperatures between 20 °C and 45 °C?
Which temperature classification prefers temperatures between 20 °C and 45 °C?
What is the maximum temperature at which Thermophiles can grow optimally?
What is the maximum temperature at which Thermophiles can grow optimally?
Which classification of microbes is likely to be found in permanently cold environments?
Which classification of microbes is likely to be found in permanently cold environments?
What describes the proteins of Psychrophiles that aid in their survival at low temperatures?
What describes the proteins of Psychrophiles that aid in their survival at low temperatures?
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Which type of microorganism thrives at temperatures above 80 °C?
Which type of microorganism thrives at temperatures above 80 °C?
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What is a primary challenge for microbial life at low temperatures?
What is a primary challenge for microbial life at low temperatures?
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How do Thermophiles and Hyperthermophiles adapt their membrane composition?
How do Thermophiles and Hyperthermophiles adapt their membrane composition?
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What is one of the adaptations Psychrophiles possess for membrane fluidity?
What is one of the adaptations Psychrophiles possess for membrane fluidity?
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Study Notes
Microbial Temperature Classifications
- Optimum Growth Temperature: Ideal temperature for microbial growth.
- Minimum Growth Temperature: Lowest temperature for survival and replication.
- Maximum Growth Temperature: Highest temperature for microbial growth.
Lake Whillans Exploration
- Expected limited life due to cold, nutrient-poor conditions.
- Discovered a rich diversity of microbial life.
Deep-Sea Vents
- Host extreme heat-loving bacteria, surviving at temperatures up to 340 °C.
Mesophiles
- Thrive in moderate temperatures between 20 °C and 45 °C.
- Includes important human microbiota and pathogens like E. coli and Salmonella.
Psychrotrophs (Psychrotolerant)
- Prefer cooler temperatures ranging from 4 °C to 25 °C.
- Common in temperate climates and responsible for spoilage in refrigerated food.
Psychrophiles (Cold-loving organisms)
- Grow at 0 °C and below, optimal around 15 °C.
- Typically do not survive above 20 °C.
- Found in permanent cold environments like deep ocean waters and are crucial decomposers in cold climates.
Thermophiles (Heat-loving organisms)
- Optimal growth between 50 °C and 80 °C.
- Do not grow at room temperature.
- Commonly located in environments like hot springs and compost piles, with examples including Thermus aquaticus and Geobacillus spp.
Hyperthermophiles
- Thrive at temperatures between 80 °C and 110 °C, with some surviving above 121 °C.
- Identified in extreme environments such as hydrothermal vents, with examples like Pyrobolus and Pyrodictium.
Adaptation to Extreme Temperatures
- Low Temperatures: Cause loss of membrane fluidity, ice damage, slowed chemical reactions, and rigid proteins prone to denaturation.
- High Temperatures: Result in protein and nucleic acid denaturation, increased fluidity disrupting metabolism.
- Applications of these temperature effects include sterilization and pasteurization.
Psychrophiles' Protein Characteristics
- Flexible proteins with fewer stabilizing bonds.
- Utilize antifreeze proteins and unsaturated lipids to maintain membrane fluidity.
- Slower growth rates compared to mesophiles; can endure freezing and are stable with glycerol storage at -80 °C.
Thermophiles' and Hyperthermophiles' Macromolecule Differences
- Elevated ratio of saturated lipids limits membrane fluidity, enhancing survival at high temperatures.
- DNA shows higher guanine-cytosine content for stability.
- Proteins feature additional bonds and modified amino acids for increased resistance to denaturation.
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