Untitled Flashcards Set

Microbial Nutrition

Substances required for microbial biosynthesis and energy.

Nutrients

Raw materials necessary for microbial growth.

Growth Requirements

Factors needed for microorganisms to grow.

Physical Requirements

Environmental conditions affecting microbial growth.

Chemical Requirements

Essential elements for microbial metabolism.

Temperature

Optimal heat range for microbial growth.

Psychrophiles

Microbes thriving at cold temperatures, 0-15°C.

Psychrotrophs

Cold-loving organisms growing at 20-30°C.

Mesophiles

Moderate temperature microbes, optimal at 25-40°C.

Thermophiles

Heat-loving microbes, grow at 50-60°C.

Hyperthermophiles

Microbes thriving at extreme temperatures, 80°C+.

pH

Measure of acidity or alkalinity in solutions.

Acidophiles

Bacteria thriving in acidic environments.

Chemical Buffers

Substances used to stabilize pH in media.

Osmotic Pressure

Pressure from dissolved molecules in a solution.

Plasmolysis

Cell shrinkage due to high osmotic pressure.

Halophiles

Microorganisms requiring high salt concentrations.

Diatoms

Unicellular algae important in oceanic food chains.

Dinoflagellates

Salt-tolerant algae, key in marine ecosystems.

Hypertonic Solution

Solution with higher solute concentration than cell.

Trace Elements

Micronutrients essential for microbial growth.

Carbon

Structural backbone of living matter, sourced from CO2 or organic materials.

Autotrophs

Organisms using CO2 as their carbon source.

Heterotrophs

Organisms using organic compounds for carbon.

Photoautotroph

Uses light for energy and CO2 for carbon.

Photoheterotroph

Uses light for energy and organic compounds for carbon.

Chemoautotroph

Uses inorganic compounds for energy and CO2 for carbon.

Chemoheterotroph

Uses organic compounds for energy and carbon.

Aerobic Organisms

Require oxygen for energy-yielding growth.

Anaerobic Organisms

Grow without oxygen; include obligate and facultative types.

Facultative Anaerobes

Grow in presence or absence of oxygen.

Obligate Anaerobes

Cannot tolerate oxygen; harmed by reactive oxygen species.

E. coli

Example of facultative anaerobe; grows with or without oxygen.

Clostridium

Example of obligate anaerobe; harmed by oxygen.

Bacteriodes

Obligate anaerobes; do not tolerate oxygen.

Fungi

Eukaryotic organisms; decomposers in ecosystems.

Microaerophiles

Require low levels of oxygen for growth.

Nitrogen-fixing bacteria

Bacteria that obtain nitrogen from the atmosphere.

Rhizobium

A nitrogen-fixing bacterium found in soil.

Azotobacter

Another nitrogen-fixing bacterium in soil.

Sulfur

Essential for protein synthesis in bacteria.

Phosphorus

Key element for nucleic acid and phospholipid synthesis.

Organic growth factors

Vitamins and amino acids required by some bacteria.

Fastidious bacteria

Bacteria with complex nutrient requirements.

Culture medium

Nutrient environment for microbial growth in labs.

Pure culture

Culture with only one type of organism present.

Mixed culture

Culture with multiple different organisms present.

Sterile medium

Medium free of all forms of life before inoculation.

Nutrient agar

Solid medium made with nutrient broth and agar.

Mannitol Salt Agar

Selective for halophilic and gram-positive bacteria.

Blood agar

Enriched medium, differentiates hemolytic bacteria.

Anaerobic atmosphere

Oxygen-free environment required for anaerobic microorganisms.

Simple media

Contains carbon dioxide, nitrate, and minerals.

Complex media

Nutrients from yeast, meat, or plant extracts.

Peptones

Protein digests providing amino acids and peptides.

Streak plate method

Technique to isolate bacteria on agar surface.

Pour plate method

Dilution technique to isolate bacteria in agar.

Generation time

Time for microbial population to double in numbers.

Growth curve

Graph showing bacterial population phases over time.

Lag phase

Initial phase where bacteria acclimate to environment.

Log phase

Exponential growth phase with rapid population doubling.

Stationary phase

Population plateau due to balanced reproduction and death.

Decline phase

Rapid die-off of bacteria, population decreases.

Environmental conditions

Factors influencing microbial growth and survival.

Antimicrobial agents

Substances that inhibit microbial growth.

Chromosomal DNA

Genetic material that duplicates during bacterial reproduction.

Colony

Visible mass of microorganisms grown on a medium.