Microbiology Midterm 3
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Questions and Answers

What does the presence of large numbers of microorganisms in water indicate?

High nutrient levels.

In which zone would you find photosynthetic algae?

Limnetic zone.

What is the primary role of bioluminescent bacteria in marine environments?

They assist benthic-dwelling fish in attracting and capturing prey.

Which microorganisms are dominant below 100 meters in seawater?

<p>Archaea, particularly Crenarchaeota.</p> Signup and view all the answers

Why are purple and green sulfur bacteria usually found deep in freshwater rather than at the surface?

<p>They require low light and anoxic conditions for photosynthesis.</p> Signup and view all the answers

What is an extremophile?

<p>An extremophile is an organism that thrives in extreme environmental conditions.</p> Signup and view all the answers

Identify two extreme habitats where extremophiles can be found.

<p>Hot springs and salt flats.</p> Signup and view all the answers

Define symbiosis.

<p>Symbiosis is a close, long-term interaction between two different biological species.</p> Signup and view all the answers

What is mycorrhiza?

<p>Mycorrhiza is a type of fungal association with plant roots that enhances nutrient uptake.</p> Signup and view all the answers

Differentiate between endomycorrhizae and ectomycorrhizae.

<p>Endomycorrhizae penetrate the root cells while ectomycorrhizae form a sheath around the outside of the roots.</p> Signup and view all the answers

Give an example of an organism that forms endomycorrhizae.

<p>Glomus species.</p> Signup and view all the answers

Provide an example of an organism that forms ectomycorrhizae.

<p>Pinus (pine trees).</p> Signup and view all the answers

What key components make a scientific paper well organized?

<p>It should have a clear introduction, detailed methods, results without discussion, and an integrating discussion section.</p> Signup and view all the answers

What are extremophiles and where do they typically thrive?

<p>Extremophiles are microorganisms that live in extreme conditions, such as high pH, temperature, and salinity. They typically thrive in environments like hot springs and salt lakes.</p> Signup and view all the answers

What is the difference between mutualism and commensalism?

<p>In mutualism, both organisms benefit, while in commensalism, one organism benefits and the other is unaffected.</p> Signup and view all the answers

Identify two types of mycorrhizae.

<p>The two types of mycorrhizae are endomycorrhizae and ectomycorrhizae.</p> Signup and view all the answers

Why are there millions of bacteria per gram of soil?

<p>There are millions of bacteria per gram of soil because they play essential roles in nutrient cycling and the decomposition of organic matter.</p> Signup and view all the answers

What role do microorganisms play in biogeochemical cycles?

<p>Microorganisms oxidize and reduce elements to meet their metabolic needs, thereby recycling these elements in biogeochemical cycles.</p> Signup and view all the answers

What is metagenomics and its purpose in studying microbiomes?

<p>Metagenomics is a tool that uses rRNA genes to analyze microbiomes, aiming to detail microbial populations in various environments.</p> Signup and view all the answers

Provide an example of a parasitic relationship.

<p>An example of a parasitic relationship is a disease-causing microbe that derives nutrients at the expense of its host.</p> Signup and view all the answers

What is the wavelength range of ultraviolet rays?

<p>Ultraviolet rays range from 380 nm to 10 nm.</p> Signup and view all the answers

How can waterborne diseases be transmitted?

<p>Waterborne diseases are transmitted through water contaminated by sewage.</p> Signup and view all the answers

Name a disease that can be spread through airborne transmission.

<p>Tuberculosis is an example of a disease spread through airborne transmission.</p> Signup and view all the answers

What type of transmission occurs when pathogens are carried on the feet of arthropods?

<p>This is known as mechanical transmission.</p> Signup and view all the answers

How do zoonoses typically transmit to humans?

<p>Zoonoses are typically transmitted to humans through contact with infected animals.</p> Signup and view all the answers

What is an example of biological transmission?

<p>Malaria transmitted by Anopheline mosquitoes is an example of biological transmission.</p> Signup and view all the answers

What is contact transmission?

<p>Contact transmission occurs when pathogens are spread through physical interaction.</p> Signup and view all the answers

What is the significance of airborne pathogens traveling such long distances?

<p>Airborne pathogens can spread diseases over great distances, increasing outbreak risks.</p> Signup and view all the answers

What was John Snow's significant contribution to epidemiology in 1848?

<p>He mapped the occurrence of cholera in London.</p> Signup and view all the answers

How did Ignaz Semmelweis impact maternal health in 1847?

<p>He showed that handwashing decreased the incidence of puerperal sepsis.</p> Signup and view all the answers

What did Florence Nightingale demonstrate regarding sanitation?

<p>She showed that improved sanitation decreased the incidence of epidemic typhus.</p> Signup and view all the answers

What are the two types of epidemiology that involve comparing different groups?

<p>The two types are descriptive epidemiology and analytical epidemiology.</p> Signup and view all the answers

What is experimental epidemiology primarily concerned with?

<p>It involves testing hypotheses through controlled experiments, such as clinical trials.</p> Signup and view all the answers

Why is it usually necessary to specify the term fecal coliform in water quality assessments?

<p>Fecal coliforms are specifically associated with fecal contamination, indicating a higher level of health risk from pathogens compared to total coliforms.</p> Signup and view all the answers

How do flocculants such as alum facilitate the removal of colloidal impurities from water?

<p>Alum binds with colloidal particles to form larger aggregates (flocs) that can then settle out of the water during sedimentation.</p> Signup and view all the answers

What is the primary goal of the primary sewage treatment process?

<p>The primary sewage treatment aims to remove solids from wastewater, reducing the overall solid content and sludge formation.</p> Signup and view all the answers

What is the range of BOD removal achieved through primary sewage treatment?

<p>Primary sewage treatment typically removes 25-35% of the biochemical oxygen demand (BOD).</p> Signup and view all the answers

Describe the functioning of an activated sludge system during secondary sewage treatment.

<p>In an activated sludge system, air is pumped through wastewater, promoting the growth of aerobic microorganisms that metabolize organic matter.</p> Signup and view all the answers

What role do trickling filters play in secondary sewage treatment?

<p>Trickling filters allow sewage to be sprayed over a bed of rocks or plastic, where aerobic microbes form biofilms and help to degrade organic matter.</p> Signup and view all the answers

What process is used to disinfect sewage before its release into the environment?

<p>Sewage is typically disinfected by chlorination prior to its release into water bodies.</p> Signup and view all the answers

What is the purpose of anaerobic sludge digesters in sewage treatment?

<p>Anaerobic sludge digesters break down organic solids in the sludge, producing methane and carbon dioxide through the activity of anaerobic bacteria.</p> Signup and view all the answers

What type of sewage treatment is typically utilized in areas with low population density and why?

<p>Septic tanks are used for primary sewage treatment in sparsely populated areas for their cost-effectiveness and simplicity.</p> Signup and view all the answers

Which type of sewage treatment is specifically designed to remove nearly all phosphorus from sewage?

<p>Tertiary sewage treatment is designed to remove remaining BOD, nitrogen, and phosphorus effectively.</p> Signup and view all the answers

Flashcards

Extremophile

Organisms thriving in extreme environments like very hot or very cold temperatures, high salinity, or intense pressures.

Symbiosis

A close and often long-term interaction between two or more different species.

Mycorrhiza

A mutually beneficial relationship between fungi and plant roots.

Endomycorrhiza

A type of mycorrhiza where fungal hyphae penetrate plant root cells.

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Ectomycorrhiza

A type of mycorrhiza where fungal hyphae form a sheath around plant roots, but don't penetrate root cells.

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Arbuscular mycorrhizae

A type of endomycorrhiza where fungal hyphae form arbuscules, tree-like structures within root cells.

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Ectomycorrhizal fungi

A type of ectomycorrhiza where fungal hyphae form a mantle around roots, and extend into the soil.

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Littoral Zone

The area of a lake or pond near the shore with rooted vegetation.

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Commensalism

A symbiotic relationship where one organism benefits and the other is neither harmed nor helped.

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Limnetic Zone

The surface of open water in a lake or pond, away from the shore, where photosynthetic algae thrive.

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Profundal Zone

The deeper water below the limnetic zone, with low oxygen levels, where anaerobic purple and green bacteria thrive.

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Mutualism

A symbiotic relationship where both organisms benefit.

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Parasitism

A symbiotic relationship where one organism benefits at the expense of the other.

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Benthic Zone

The bottom sediment of a lake or pond, where there's no light or oxygen, and anaerobic bacteria like Desulfovibrio and methane-producing bacteria are active.

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Why are purple and green sulfur bacteria found in deeper water?

Purple and green sulfur bacteria are photosynthetic, but prefer deeper water because they use hydrogen sulfide as an electron donor, which is more abundant in darker, deeper zones.

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Metagenomics

The study of all the genetic material present in an environmental sample.

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Descriptive epidemiology

A type of epidemiology that looks back at the past to analyze and understand the causes of a disease.

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Analytical epidemiology

A type of epidemiology that compares two groups to identify the potential cause of a disease.

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Experimental epidemiology

A type of epidemiology that uses controlled experiments to test a hypothesis about a disease.

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John Snow

A scientist known for mapping cholera outbreaks in London, showing that the disease was spread through contaminated water.

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Ignaz Semmelweis

A scientist who discovered that handwashing reduced the incidence of puerperal sepsis in hospitals.

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Vehicle Transmission

Transmission of infectious agents through inanimate objects like water, food, or air.

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Waterborne Transmission

The spread of a disease through contaminated water, often originating from sewage.

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Foodborne Transmission

The transfer of pathogens through food that's not cooked properly or contaminated during preparation.

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Airborne Transmission

Tiny particles less than 5 µm in diameter, suspended in air and capable of carrying pathogens. These particles can remain airborne for a long time.

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Vector Transmission

Transmission through living organisms like fleas, ticks, and mosquitoes.

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Mechanical Transmission

When an arthropod carries a pathogen on its body and transmits it mechanically, without the pathogen multiplying inside the vector

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Biological Transmission

When a pathogen multiplies within a vector, such as a mosquito, and is transmitted through bites or feces.

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Carrier

A person or animal who carries and transmits a disease without showing symptoms.

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Why is it usually necessary to specify the term fecal coliform when discussing bacterial indicators of water pollution?

Coliform bacteria are a general indicator of fecal contamination in water. Fecal coliform bacteria are a more specific indicator of the presence of human or animal waste in the water, which is a greater health risk.

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How do flocculants remove colloidal impurities from water?

Coagulation involves adding chemicals like alum to water to clump together small particles, making them heavier and easier to settle out during sedimentation. This removes colloidal materials, bacteria, and viruses.

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What does biochemical oxygen demand (BOD) measure?

The biochemical oxygen demand (BOD) is a measure of the amount of biodegradable organic matter present in water. It is determined by the amount of oxygen required by bacteria to break down this organic matter.

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What does primary sewage treatment mainly remove?

Primary treatment removes solid materials from sewage through sedimentation tanks. This process removes approximately 25-35% of the BOD.

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What is the main purpose of secondary sewage treatment?

Secondary treatment aims to remove the bulk of the remaining organic matter. This is achieved through various processes like activated sludge systems, trickling filters, and rotating biological contactors, which utilize aerobic bacteria to break down organic matter.

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How do activated sludge systems work?

Activated sludge systems pass air through sewage after primary treatment, encouraging the growth of aerobic bacteria that metabolize organic matter. This process achieves a significant reduction in BOD.

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How do trickling filters work in secondary sewage treatment?

Trickling filters involve spraying sewage over a bed of rocks or plastic, where a biofilm of aerobic microbes grows and breaks down organic matter. This method also significantly reduces BOD.

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How is sewage disinfected before release?

Sewage is disinfected by chlorination before being released to the environment. This ensures a safe level of pathogens is eliminated.

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What happens during sludge digestion?

Anaerobic sludge digesters treat sludge from primary treatment, using anaerobic bacteria to break down organic solids into methane and carbon dioxide. This process also generates biogas for energy.

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What is the purpose of tertiary sewage treatment?

Tertiary sewage treatment focuses on removing remaining pollutants, such as nitrogen and phosphorus. This step involves physical and chemical methods, such as chlorination, to achieve a high level of water purification.

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Study Notes

Overview

  • This document is a collection of microbiology lecture notes.
  • The notes cover topics such as introductions, referencing, dissecting scientific papers, microbial diversity and habitats, soil microbiology, biogeochemical cycles, the carbon cycle, the nitrogen cycle, the sulfur cycle, the phosphorous cycle, degradation of synthetic chemicals, aquatic microbiology, and sewage treatment, and the role of microorganisms in water quality.
  • Various learning objectives and check your understanding questions are also included.

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Description

This quiz explores the diverse roles and characteristics of microorganisms in aquatic ecosystems, including extremophiles and their habitats. Test your understanding of microbial life, symbiotic relationships, and their contributions to biogeochemical cycles.

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