Microbial Ecology and General Ecological Concepts

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Questions and Answers

What color indicates the surface depth of a biofilm when observing through phase contrast microscopy?

Red (correct)

Green

Yellow

Blue

What substance is used to stain a biofilm developed on stainless-steel to visualize nucleic acids?

Crystal Violet

DAPI (correct)

Iodine

Methylene Blue

What distinguishes a microbial mat from a standard biofilm?

Microbial mats are made up of single-celled organisms only.

Microbial mats are extremely thick and consist of various microorganisms. (correct)

Microbial mats are less complex than biofilms.

Microbial mats can only develop in freshwater environments.

What environmental condition is often associated with the presence of microbial mats?

Metal-rich, low-pH environments Signup and view all the answers

Which type of bacteria are primarily found in iron-oxidizing microbial mats?

Sulfur-oxidizing bacteria Signup and view all the answers

What is the role of the Diel cycle in relation to microbial mats?

It influences the microbial diversity within mats. Signup and view all the answers

Which process is most associated with the formation of extracellular glucans in a dental biofilm?

Anaerobic fermentation of sucrose Signup and view all the answers

What indicates the depth within a biofilm when stained with iodine solution?

Coloration resulting from extracellular glucans Signup and view all the answers

What significant paradigm in microbiology involves isolating organisms from complex communities?

Pure Culture Paradigm Signup and view all the answers

Which bacterium did Robert Koch discover as a cause of anthrax?

Bacillus anthracis Signup and view all the answers

What medium did Koch develop for obtaining pure cultures?

Agar media Signup and view all the answers

What was the main point of Oscar Brefield's statement about working with impure cultures?

It produces unreliable results. Signup and view all the answers

What is the significance of the zone of no bacterial growth observed in Fleming's experiment?

It demonstrates the effectiveness of antibiotics. Signup and view all the answers

What technological advancement did Koch's pure culture paradigm provide for microbiology?

Isolation of key microbial processes Signup and view all the answers

Which disease did Robert Koch NOT study directly in his research?

Rabies Signup and view all the answers

What discovery resulted from Fleming's examination of an impure culture contaminated by Penicillium?

The drug penicillin Signup and view all the answers

What kind of measurements are sufficient in many studies for assessing microbial activities?

Direct chemical measurements Signup and view all the answers

Why is it important to use proper killed cell controls in chemical assays?

To differentiate microbial chemical actions from abiotic processes Signup and view all the answers

Which method increases the sensitivity of measuring metabolites in microbial activity assessments?

Application of radioisotopes Signup and view all the answers

What types of substances can microsensors detect based on electrochemical reactions?

Various gases, ions, and metabolites Signup and view all the answers

What can small glass electrodes connected to microsensors measure?

pH, oxygen, CO2, and other compounds Signup and view all the answers

In measuring microbial activities in coral, what was used for calibration?

A fragment of coral skeleton Signup and view all the answers

What is a characteristic of microsensors used in microbial activity measurement?

They have tip sizes ranging from 2 to 100 μm in diameter Signup and view all the answers

How is the current in a microelectrode affected in the presence of a substrate?

It fluctuates based on substrate concentration. Signup and view all the answers

What is the significance of the Winogradsky column?

It demonstrates microbial communities along an oxygen gradient. Signup and view all the answers

What was one of Martinus Beijerinck's major contributions to microbiology?

He isolated nitrogen-fixing bacteria. Signup and view all the answers

Which statement correctly describes the concept of 'microbial ubiquity'?

Microorganisms are universally present, influenced by conditions. Signup and view all the answers

What did Cornelius Bernardus van Niel contribute to our understanding of photosynthesis?

He identified oxygen as a byproduct from water, not CO2. Signup and view all the answers

Which of the following best describes chemoautotrophy?

Deriving energy from chemical oxidation and carbon from CO2. Signup and view all the answers

Who is considered the founder of soil microbiology?

Sergei Winogradsky Signup and view all the answers

What key concept did Albert Jan Kluyver help promote in microbiology?

The unifying metabolic features among microbes. Signup and view all the answers

What role did Sergei Winogradsky play in the understanding of element transformations?

He identified the importance of microbes as major players in element transformations. Signup and view all the answers

What is the goal of an enrichment culture?

To provide a medium that favors a specific metabolic function. Signup and view all the answers

Which of the following best describes the contribution of the Dutch Delft School to microbiology?

Significant advancements in understanding microbial physiology and ecology. Signup and view all the answers

What is the definition of a population in microbial ecology?

Microorganisms of the same species residing together. Signup and view all the answers

What is the significance of microbial guilds in an ecosystem?

They represent metabolically related populations that interact. Signup and view all the answers

Which of the following accurately describes an ecosystem?

The sum total of all organisms and abiotic factors in an environment. Signup and view all the answers

What is species abundance in microbial ecology?

The proportion of each species in an ecosystem. Signup and view all the answers

What role do heterotrophs play in microbial metabolism?

They consume organic compounds for energy. Signup and view all the answers

Which characteristics are essential for microbial growth?

Proper nutrients and suitable physiochemical conditions. Signup and view all the answers

Which of the following accurately describes the function of biogeochemical cycling?

It pertains to the cycling of elements like C, O, N, and P. Signup and view all the answers

Which of the following is NOT a type of extremophile?

Mesophiles Signup and view all the answers

What limits the study of microorganisms in their natural environments?

Technological and methodological constraints. Signup and view all the answers

Which statement best describes nutrient cycling in ecosystems?

Primary production and decomposition are key processes in nutrient cycling. Signup and view all the answers

What type of environments do extremophiles thrive in?

Extremes in temperature, pressure, and other conditions. Signup and view all the answers

What is the primary focus of microbial ecology as a field of study?

The intricate relationships between microorganisms and their environments. Signup and view all the answers

In the context of microbial diversity, what does species richness refer to?

The total number of different species in an ecosystem. Signup and view all the answers

What is the main activity measured when studying microorganisms within an ecosystem?

Primary production and decomposition of organic matter. Signup and view all the answers

Study Notes

### Microbial Ecology

Study of inter-relationships between microorganisms and their environments, from the individual cell to the ecosystem level.

General Ecological Concepts

Ecosystem: all organisms and abiotic factors in a specific environment.
Habitat: portion of an ecosystem where a community could reside.
Population: a group of microorganisms of the same species residing in the same place at the same time.
Community: consists of populations living in association with other populations.
Guild: sets of metabolically related microbial populations that interact with macroorganisms and abiotic factors in the ecosystem.
Niche: habitat shared by a guild, supplies nutrients and conditions for growth.
Species richness: total number of different species present in an ecosystem.
Species abundance: proportion of each species in an ecosystem.

Microbial Ecology Considerations

The role of microbes in ecosystem niches & biogeochemical cycling.
Microbes are found in a wide variety of environments including "extremes" such as high and low temperatures, pH, pressure, salinity, and anoxic habitats.

Microbial Ecology Objectives

Biodiversity of microorganisms in nature and interactions within communities.
Measurement of microbial activities and monitoring of effects on ecosystems.
Typical microbial activities measured:
- Primary production of organic matter (phototrophic, chemolithotrophic activity)
- Decomposition of organic matter (chemoorganotrophic/heterotrophic activity)
- Biogeochemical cycling of elements

Microbial Activity Measurements in Nature

Direct chemical measurements: lactate, SO42−, and H2S can be measured using chemical assays.
Radioisotopes: high sensitivity for microbial activity measurements.
Microsensors (microelectrodes): sensitive instruments used to measure pH, oxygen, N2O, CO2, H2, H2S, and other substances.
Nanosensors: based on octaethylporphine ketone platinum (II) for measuring dissolved oxygen concentrations in coral photosynthetic activity.

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Description

Explore the fascinating relationships between microorganisms and their environments in this quiz. Covering essential concepts such as ecosystems, habitats, populations, and niches, this quiz will enhance your understanding of microbial ecology's role in various ecosystems.