Microbial Diversity Overview
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Questions and Answers

Which virus has a double-stranded DNA genome?

  • Poliovirus
  • Poxvirus (correct)
  • ADIS Virus
  • None of the above

What type of RNA does the ADIS virus contain?

  • Single-stranded DNA
  • Single-stranded RNA, positive-sense (correct)
  • Double-stranded DNA
  • Single-stranded RNA, negative-sense

Which virus is non-enveloped?

  • Poxvirus
  • Poliovirus (correct)
  • ADIS Virus
  • All of the above

What unique structural feature is associated with the ADIS virus?

<p>Reverse transcriptase enzyme (D)</p> Signup and view all the answers

Which disease is associated with the ADIS virus?

<p>AIDS (A)</p> Signup and view all the answers

What is microbial diversity primarily defined as?

<p>The variety of microorganisms found in different environments (D)</p> Signup and view all the answers

Which of the following contributes to ecological stability through microbial diversity?

<p>Decomposition and photosynthesis (B)</p> Signup and view all the answers

What role does the human microbiome play in health?

<p>Stimulates the immune system and aids in digestion (A)</p> Signup and view all the answers

Which of the following is true about the impact of microbial diversity in biotechnology?

<p>It can lead to innovations in medicine and environmental management (D)</p> Signup and view all the answers

Which microorganisms are NOT typically included in the definition of microbial diversity?

<p>Mammals (A)</p> Signup and view all the answers

What is linked to a loss of microbial diversity in humans?

<p>Increased susceptibility to diseases (A)</p> Signup and view all the answers

Why is quantifying microbial biodiversity different from that of macroorganisms?

<p>Microorganisms are mostly clonal and very small in size (C)</p> Signup and view all the answers

Which of the following is NOT a significant role of microorganisms in ecosystems?

<p>Breaking news (B)</p> Signup and view all the answers

What role do microbes play in environmental monitoring?

<p>They serve as sensitive indicators of environmental changes. (D)</p> Signup and view all the answers

Which of the following classifications was proposed by Carl Woese in the 1980s?

<p>Three-domain system (C)</p> Signup and view all the answers

What is the primary molecular basis for distinguishing between Archaea and Bacteria?

<p>Differences in nucleotide base sequences of the 16S ribosomal RNA. (D)</p> Signup and view all the answers

What makes certain microbes valuable in bioremediation efforts?

<p>Their capacity to degrade pollutants. (A)</p> Signup and view all the answers

Which family of bacteriophages is characterized by a non-contractile long tail?

<p>Siphoviridae (C)</p> Signup and view all the answers

Which of the following is true regarding Myoviridae bacteriophages?

<p>They have a contractile tail. (D)</p> Signup and view all the answers

Which of the following organisms are classified as eukaryotes?

<p>Fungi (D)</p> Signup and view all the answers

Why are viruses considered a separate entity in biological classification?

<p>They exhibit traits of both living and non-living characteristics. (D)</p> Signup and view all the answers

What is the morphology of T7 phage in the Podoviridae family?

<p>Nonenveloped with a short contractile tail (D)</p> Signup and view all the answers

What insight can studying microbial diversity provide?

<p>Insights into the evolutionary history of life on Earth. (D)</p> Signup and view all the answers

What type of nucleic acid do lambda phages possess?

<p>Linear dsDNA (D)</p> Signup and view all the answers

Which characteristic is common to all families under the order Caudovirales?

<p>They all have some form of tail. (C)</p> Signup and view all the answers

Which of the following is NOT a category of the three-domain system?

<p>Fungi (D)</p> Signup and view all the answers

How do Siphoviridae bacteriophages attach to bacterial cells?

<p>Using tail fibers (C)</p> Signup and view all the answers

What distinguishes the Podoviridae family from others in the Caudovirales order?

<p>They have a short tail. (D)</p> Signup and view all the answers

What type of structure does bacteriophage T4 possess?

<p>Complex structure allowing specific attachment (B)</p> Signup and view all the answers

Which type of genetic material is found in the Tobacco Mosaic Virus (TMV)?

<p>Single-stranded positive-sense RNA (D)</p> Signup and view all the answers

What structural characteristic distinguishes the M13 phage from other types of bacteriophages?

<p>It is filamentous and nonenveloped. (C)</p> Signup and view all the answers

What is the primary method by which M13 phage initiates infection in bacterial cells?

<p>By binding to pili on the bacterial cell surface. (A)</p> Signup and view all the answers

Which virus is known for producing characteristic vesicular skin lesions?

<p>Poxvirus (D)</p> Signup and view all the answers

What is the typical size range of a poxvirus genome?

<p>130–260 kb (D)</p> Signup and view all the answers

Which of the following statements about the capsid of TMV is correct?

<p>It is composed of 2,130 identical protein subunits arranged in a helical pattern. (B)</p> Signup and view all the answers

What is a notable feature of poxviruses compared to many other viruses?

<p>They lack typical icosahedral or helical symmetry. (A)</p> Signup and view all the answers

What is the shape of the Tobacco Mosaic Virus (TMV)?

<p>Rod-shaped (B)</p> Signup and view all the answers

What character of viruses allows them to harm host cells?

<p>Ability to multiply inside a host cell (C)</p> Signup and view all the answers

Which of the following statements about the nucleic acid in viruses is true?

<p>Nucleic acids in viruses can be both linear and circular (D)</p> Signup and view all the answers

What feature is NOT characteristic of virus structure?

<p>Cellular organization (A)</p> Signup and view all the answers

What defines the term 'virion' in the context of viruses?

<p>An inactive virus particle outside of a host (C)</p> Signup and view all the answers

Which of the following describes the size range of viruses?

<p>10 to 350 nm (C)</p> Signup and view all the answers

What type of symmetry can a viral capsid exhibit?

<p>Cubic symmetry (D)</p> Signup and view all the answers

What is a common attribute of viruses as compared to bacteria?

<p>Viruses can pass through bacterial filters (A)</p> Signup and view all the answers

What defines the metabolic function of viruses?

<p>They lack any metabolic activity (D)</p> Signup and view all the answers

Flashcards

Microbial diversity

The variety of microorganisms found in different environments, including their genetic variation and metabolic roles.

Microbial diversity study

The study of the variety and relationships of microorganisms.

Ecological importance of microbial diversity

Microorganisms are essential for nutrient cycling processes like decomposition, nitrogen fixation, and photosynthesis.

Human microbiome

The community of trillions of microbes living in and on our bodies.

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Human Health and Microbial Diversity

A diverse microbiome is linked to better health outcomes, while a loss of diversity can contribute to diseases like obesity, allergies, and autoimmunity.

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Biotechnology and Microbial Diversity

Microorganisms are used in the production of antibiotics, enzymes, biofuels, and fermented foods.

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Innovation through Microbial Diversity

The discovery of new microbes and their unique metabolic pathways can lead to innovations in medicine, agriculture, and environmental management.

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Challenges in quantifying microbial biodiversity

The small size, clonal nature, and high diversity of microorganisms make quantifying their biodiversity fundamentally different from quantifying macroorganisms.

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Microbial Communities as Environmental Indicators

Changes in microbial communities can signal environmental disturbances like pollution or climate change.

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Bioremediation: Microbes as Clean-up Crews

Certain microbes can break down pollutants, helping to clean up contaminated environments.

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Microbial Diversity: Tracing Life's Journey

Studying microbial diversity helps us understand the evolutionary history of life on Earth.

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Shift From Phenotype to Genotype in Classification

The classification of organisms was traditionally based on physical characteristics. But in the 1970s, analyzing RNA sequences became crucial for identifying organisms.

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Woese's Discovery: The Three-Domain System

Carl Woese used RNA sequencing to identify a new domain of life - Archaea.

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Archaea: A Separate Domain

Archaea were originally classified as bacteria, but are now recognized as separate due to key differences in their ribosomal RNA sequence.

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Viruses: Between Life and Non-life

Although viruses display some traits of living organisms, they lack essential characteristics, making them a separate category.

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Viruses: Unfit for the Five Kingdoms

Whittaker's five-kingdom classification does not include viruses because their unique nature makes them difficult to classify.

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Viruses: Obligate Intracellular Parasites

Viruses are considered obligate intracellular parasites, meaning they can only replicate inside living cells. They lack the machinery for independent metabolism and must rely on their host's resources for survival and reproduction.

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What is a capsid?

The protein coat surrounding the viral genome is called the capsid. It defines the virus's shape and protects the genetic material. Each capsid is made up of smaller protein subunits called capsomers.

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Viral Nucleic Acid: RNA or DNA?

Viruses can be classified based on their genetic material. They can contain either RNA or DNA, but never both. The nucleic acid can be single-stranded or double-stranded and linear or circular.

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How big are viruses?

Viruses are microscopic particles, meaning they are too small to be seen with a standard light microscope. They are typically measured in nanometers (nm) and can vary in size from 10 nm to 350 nm.

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What is a virion?

The complete, infectious viral particle is called a virion. It contains the viral genome and the capsid, and it's the form in which viruses exist outside of a host cell.

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Viruses: Lack of Metabolism

Unlike living cells, viruses lack the ability to perform metabolic processes like energy production and protein synthesis. They depend entirely on their host cells for these essential functions.

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Viruses: Lack of Cellular Organization

Viruses lack true cellular organization. They consist of a nucleic acid core surrounded by a protein coat, lacking the membrane-bound organelles found in living cells.

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Viral Mutations

Viruses can undergo mutations, which alter their genetic makeup, potentially leading to changes in their characteristics. Viruses can evolve and become resistant to antiviral drugs or adapt to new hosts.

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What are Bacteriophages?

Bacteriophages are viruses that infect bacteria. They are classified based on their tail structures (contractile or non-contractile), genome type (DNA or RNA), and infection methods.

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What is M13 Phage?

M13 Phage is a type of filamentous phage that infects bacteria. It has a single-stranded DNA genome and attaches to specific pili on the bacterial surface for infection.

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What is Tobacco Mosaic Virus?

Tobacco Mosaic Virus (TMV) is a well-studied plant virus. It's rod-shaped, composed of a helical capsid made of coat proteins, and contains a single-stranded RNA molecule.

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What are Poxviruses?

Poxviruses are large, brick-shaped animal viruses with a complex internal structure. They have a double-stranded DNA genome, a complex capsid without typical symmetry, and a double-layered envelope.

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Myoviridae

A type of bacteriophage with a contractile tail, allowing it to inject its genetic material into a bacterial cell.

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Podoviridae

Bacteriophages with short tails, known for their rapid infection of bacteria.

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Siphoviridae

Bacteriophages with long, non-contractile tails, often involved in lysogeny (integration of phage DNA into bacterial genome).

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Attachment Fibers

The protein structure at the end of a bacteriophage tail that helps it attach to specific receptors on the bacterial cell surface.

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Baseplate

A complex protein structure at the base of the bacteriophage tail, involved in attaching the phage to the bacterial cell and injecting its genetic material.

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Bacteriophage Nucleic Acid

The genetic material carried by a bacteriophage, typically DNA, but sometimes RNA. It can be linear or circular, double-stranded or single-stranded.

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Lysogeny

The process where a phage integrates its DNA into the bacterial chromosome, becoming a prophage and potentially influencing the host's behavior.

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Lytic Cycle

The process where a phage replicates itself within a bacterial cell, eventually leading to lysis (bursting) of the host cell.

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Human Immunodeficiency Virus (HIV)

A virus that infects humans, often causing a wide range of symptoms. It targets the immune system, weakening it and making the body vulnerable to other infections.

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Acquired Immunodeficiency Syndrome (AIDS)

A disease caused by HIV, ultimately leading to a compromised immune system and increased susceptibility to infections.

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Retrovirus

A type of virus characterized by its use of RNA as its genetic material.

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Reverse Transcriptase

A crucial enzyme present in retroviruses, essential for the replication process. It converts the viral RNA into DNA, integrating it into the host cell's genome.

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gp120

A protein molecule found on the surface of HIV, essential for viral attachment and entry into host cells.

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Study Notes

Microbial Diversity

  • Microorganisms existed billions of years before multicellular life
  • First observed by Antonie van Leeuwenhoek in the 17th century
  • Advanced microscopy, culturing methods, and molecular biology expand understanding of microbial diversity
  • Microbial diversity is distinct from macroorganism diversity, due to the immense diversity of microorganisms, their small size, and their clonal nature.

Defining Microbial Diversity

  • Microbial diversity encompasses the variety of microorganisms in diverse environments (soil, water, extreme habitats)
  • Includes species richness, genetic diversity within species, and the variety of metabolic/ecological roles
  • Key microbial groups include: Bacteria, Archaea, Fungi, Protozoa, Algae, and Viruses

Importance of Microbial Diversity

Ecological Stability

  • Microbes are vital to biogeochemical cycles (carbon, nitrogen, sulfur)
  • Decomposition, nitrogen fixation, and photosynthesis rely on microbial processes
  • These processes are essential for life on Earth

Human Health

  • The human microbiome consists of trillions of microbes
  • Essential for digestion, vitamin production, immune system modulation, and pathogen defense
  • Diverse microbiome associated with better health; loss linked to diseases (obesity, allergies, autoimmune disorders)

Biotechnology and Industry

  • Microbial diversity is crucial for biotechnological applications
  • Microbes are used in antibiotic production, enzyme production, biofuel production, and food fermentation

Environmental Monitoring and Bioremediation

  • Microbes are sensitive indicators of environmental change
  • Can provide early warnings of pollution and climate change
  • Some microbes can degrade pollutants, crucial for bioremediation efforts

Evolutionary Insights

  • Microbes are the first life forms on Earth
  • Studying their diversity provides insight into the evolutionary history of life and the processes that shaped our planet
  • Important for the search for life on other planets

Classification of Organisms

  • Until the 1970s, classification was primarily based on physiological differences
  • Development of rRNA analysis revolutionized microbial classification
  • The three-domain system (Bacteria, Archaea, Eukarya) now categorizes life
  • This is based on rRNA phylogenetic analyses (identifying genetic relations)

Viruses

  • Considered a separate entity, not part of Whittaker's five-kingdom classification
  • Viruses are ultramicroscopic, obligate intracellular parasites for bacteria, plants, and animals
  • Viral structure: Nucleic acid (DNA or RNA) surrounded by a protein coat (capsid) or envelope
  • Viruses multiply inside host cells, cause diseases, and are inactive outside host cells.

Viral Shapes and Classification

  • Classification based on the host they infect (plant, animal, fungal, bacterial)
  • Bacteriophages (viruses that infect bacteria) are significantly diverse
  • Bacteriophages are structured with a head, tail, tail fibers, and other components

Types of Animal Viruses

  • Poxvirus: Causes smallpox; the largest animal viruses, a brick-shaped, nonenveloped, with dsDNA, and complex structure.
  • Poliovirus: Causes Polio; the capsid is icosahedral, simple, and ssRNA. Also enveloped.
  • HIV: Causes AIDS; single-stranded RNA (ssRNA) virus with an envelope, and complex with reverse transcriptase inside.

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Related Documents

Microbial Diversity Lecture Notes PDF

Description

Explore the fascinating world of microbial diversity, which includes an array of microorganisms that play essential roles in various ecosystems. This quiz covers the history, definitions, and significance of microbial diversity, highlighting its contributions to ecological stability and biogeochemical cycles.

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