Introduction to General & Clinical Microbiology
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Questions and Answers

Living microbes are known as cellular microbes or microorganisms.

True

Microbes that live on and in our bodies are referred to as our indigenous microbiota.

True

What is the scientific term for disease-causing microbes?

Pathogens

Which of the following is NOT a category of diseases caused by pathogens?

<p>Viral intoxications</p> Signup and view all the answers

Match the following types of microbes with their characteristics:

<p>Bacteria = Unicellular, lack nuclei, contain peptidoglycan in cell walls Archaea = Unicellular, lack nuclei, cell walls made of polymers other than peptidoglycan Fungi = Eukaryotic, obtain food from other organisms, possess cell walls Protozoa = Single-celled eukaryotes, similar to animals in nutrient needs and cellular structure Algae = Unicellular or multicellular, photosynthetic, simple reproductive structures</p> Signup and view all the answers

Viruses are considered living organisms.

<p>False</p> Signup and view all the answers

What term describes the use of microbes to clean up toxic wastes and other industrial waste products?

<p>Bioremediation</p> Signup and view all the answers

The earliest known account of pestilence occurred in Egypt.

<p>True</p> Signup and view all the answers

Which two groups of microbes are considered candidates for the first microorganisms on Earth?

<p>Archaea and cyanobacteria</p> Signup and view all the answers

The human microbiome typically contains more bacteria than human cells.

<p>True</p> Signup and view all the answers

The human microbiome remains constant throughout an individual's life.

<p>False</p> Signup and view all the answers

Acellular infectious agents, such as viruses, are further divided into prokaryotes and eukaryotes.

<p>False</p> Signup and view all the answers

Which of the following is NOT a recognized category used to group Leeuwenhoek's microorganisms?

<p>Archaea</p> Signup and view all the answers

Microbiology primarily deals with cellular organisms.

<p>False</p> Signup and view all the answers

What is the term for the field of microbiology that focuses on the study of fungi?

<p>Mycology</p> Signup and view all the answers

The vast majority of microbes are pathogens.

<p>False</p> Signup and view all the answers

Opportunistic pathogens cause disease in most individuals.

<p>False</p> Signup and view all the answers

Which of the following is NOT a characteristic of bacteria?

<p>Reproduce sexually</p> Signup and view all the answers

Archaeal cell walls are composed of peptidoglycan.

<p>False</p> Signup and view all the answers

All fungi are multicellular.

<p>False</p> Signup and view all the answers

Protozoa are similar to plants in their nutrient needs and cellular structure.

<p>False</p> Signup and view all the answers

Algae can perform photosynthesis.

<p>True</p> Signup and view all the answers

Which of the following is NOT a category used to classify algae?

<p>Arrangement of flagella</p> Signup and view all the answers

Infectious diseases are caused by the ingestion of toxins produced by pathogens.

<p>False</p> Signup and view all the answers

Microbial intoxications are caused by the ingestion of toxins produced by pathogens.

<p>True</p> Signup and view all the answers

What is the term for the type of disease known as an infectious disease?

<p>Infectious disease</p> Signup and view all the answers

Cyanobacteria are photosynthetic bacteria.

<p>True</p> Signup and view all the answers

Microorganisms are only involved in the decomposition of dead organisms, not waste products.

<p>False</p> Signup and view all the answers

Saprophytes obtain nutrition from living organisms.

<p>False</p> Signup and view all the answers

What term describes the use of microorganisms to clean up toxic wastes and other industrial waste products?

<p>Bioremediation</p> Signup and view all the answers

The use of living organisms or their derivatives to make or modify useful products or processes is called biotechnology.

<p>True</p> Signup and view all the answers

The number of prokaryotes described is greater than the number of eukaryotes described.

<p>True</p> Signup and view all the answers

Many bacteria are responsible for food spoilage.

<p>True</p> Signup and view all the answers

Archaea are known to be pathogenic.

<p>False</p> Signup and view all the answers

What is the term for a community of microorganisms that associate in a biofilm?

<p>Biofilm</p> Signup and view all the answers

Prokaryotes are generally larger than eukaryotes.

<p>False</p> Signup and view all the answers

Algae can be single-celled or multicellular.

<p>True</p> Signup and view all the answers

Fungi can only reproduce asexually.

<p>False</p> Signup and view all the answers

Viruses are cellular infectious agents.

<p>False</p> Signup and view all the answers

What is the name of the procedure developed by Louis Pasteur that involves heating a liquid to kill microorganisms?

<p>Pasteurization</p> Signup and view all the answers

Which of the following is NOT a contribution attributed to Robert Koch?

<p>Developing the pasteurization process</p> Signup and view all the answers

Koch's Postulates are a set of criteria used to prove that a specific microorganism is the cause of a particular disease.

<p>True</p> Signup and view all the answers

Koch's Postulates can be universally applied to all infectious diseases.

<p>False</p> Signup and view all the answers

The work of Koch contributed significantly to the development of the germ theory of disease.

<p>True</p> Signup and view all the answers

The Golden Age of Microbiology was a period of rapid advancements in understanding the causes and prevention of infectious diseases.

<p>True</p> Signup and view all the answers

Gram staining is a widely used technique for identifying viruses.

<p>False</p> Signup and view all the answers

Semmelweis's work on handwashing was instrumental in reducing the spread of infectious diseases in hospitals.

<p>True</p> Signup and view all the answers

Lister's antiseptic technique focused on using chemicals to kill bacteria.

<p>True</p> Signup and view all the answers

Nightingale's contributions primarily focused on developing new vaccines for infectious diseases.

<p>False</p> Signup and view all the answers

Snow's work laid the foundation for the field of epidemiology.

<p>True</p> Signup and view all the answers

Jenner's work on the smallpox vaccine led to the development of the field of immunology.

<p>True</p> Signup and view all the answers

Ehrlich's development of "magic bullets" laid the foundation for the field of chemotherapy.

<p>True</p> Signup and view all the answers

Which of the following is NOT a subject of study in applied environmental microbiology?

<p>Waste management</p> Signup and view all the answers

Biotechnology involves the use of microbes to produce antibiotics.

<p>True</p> Signup and view all the answers

The Modern Age of Microbiology has focused primarily on understanding the causes of infectious diseases.

<p>False</p> Signup and view all the answers

The Modern Age of Microbiology has seen the development of gene therapy.

<p>True</p> Signup and view all the answers

The work of Kluyver and van Niel contributed significantly to the field of microbial genetics.

<p>False</p> Signup and view all the answers

The discovery of enzymes in yeast extract was pivotal in the development of biochemistry.

<p>True</p> Signup and view all the answers

The work of Avery, MacLeod, and McCarty provided evidence that genes are contained in molecules of DNA.

<p>True</p> Signup and view all the answers

The discovery of antibiotics was mainly driven by understanding the mechanisms of genetic mutation.

<p>False</p> Signup and view all the answers

The Modern Age of Microbiology has seen the development of herbicides and pesticides using microbes.

<p>True</p> Signup and view all the answers

Study Notes

Introduction to General & Clinical Microbiology

  • Microbiology is the study of microbes, which are extremely small living organisms and certain nonliving entities.
  • Living microbes include bacteria, archaea, algae, protozoa, and fungi.
  • Non-living microbes include viroids, prions, and viruses.
  • Microbes are ubiquitous, meaning they are found virtually everywhere.
  • The microbes that cause disease are called pathogens, while microbes that do not cause disease are non-pathogens.
  • Microbes living in or on our bodies are called indigenous microbiota. Some members of our indigenous microbiota are opportunistic pathogens, which are microbes that can cause disease, but usually do not.
  • Pathogens cause infectious diseases and microbial intoxications.

Outline

  • Microbial communities support and affect all life on Earth.
  • The human body has its own microbiome.
  • Microbiology has a history, with pioneers contributing to the field.
  • The microbial world is categorized into unique groups.
  • Microbiology faces ongoing challenges.

Microbes & Microbiology

  • Biology is the study of living organisms.
  • Microbiology is an advanced biological course.
  • Living microbes are cellular microorganisms.
  • Non-living microbes are acellular microorganisms.
  • Microbes are ubiquitous.
  • The scientific term for disease-causing microbes is pathogens.
  • Microbes that do not cause disease are called non-pathogens, the vast majority of microbes are non-pathogens.
  • Microbes that live on and in our bodies are called indigenous microbiota. Some members of our indigenous microbiota are opportunistic pathogens.
  • Opportunistic pathogens are microbes that can cause disease, but usually do not.
  • Pathogens cause two categories of diseases: infectious diseases and microbial intoxications.

Acellular and Cellular Microbes

  • Microbes are divided into two groups: acellular infectious agents and cellular microorganisms.
  • Acellular infectious agents include prions and viruses.
  • Cellular microorganisms are divided into two groups: prokaryotes and eukaryotes.
  • Prokaryotes include archaea and bacteria.
  • Eukaryotes include algae, fungi, and protozoa.

Microbiology

  • Carolus Linnaeus developed a taxonomic system for naming plants and animals.
  • Leeuwenhoek's microorganisms can be grouped into six categories.
    • Bacteria
    • Archaea
    • Fungi
    • Protozoa
    • Algae
    • Multicellular animals

How Can Microbes Be Classified?

  • Bacteria and archaea:

    • Unicellular, lack cell nuclei.
    • Smaller than eukaryotes.
    • Found in environments with moisture, including extreme environments.
    • Reproduce asexually.
    • Bacterial cell walls may contain peptidoglycan, while archaeal cell walls have different polymer composition.

  • Fungi:

    • Eukaryotic, with membrane-bound nuclei.
    • Obtain food from other organisms.
    • May be multicellular (molds) or unicellular (yeasts).
    • Reproduce by sexual and asexual spores.

  • Protozoa:

    • Single-celled eukaryotes, with similar nutrient needs and cellular structure to animals.

  • Algae:

    • Unicellular or multicellular.
    • Photosynthetic.
    • Simple reproductive structures.
    • Categorized by pigmentation and cell wall composition.

  • Other organisms of importance to microbiologists include viruses and parasites.

Categories of Diseases Caused by Pathogens

  • Infectious disease results from a pathogen colonizing a host.
  • Microbial intoxication results from a toxin produced by a pathogen.

Why Study Microbiology?

  • Microbes play essential roles in life on Earth.
  • Photosynthetic microbes produce oxygen.
  • Microbes decompose dead organisms and waste.
  • Saprophytes live on dead and decaying organic matter; involved in bioremediation.
  • Microbes participate in various elemental cycles.
  • Microbes serve as food for animals, aid in digestion, and produce beneficial substances.
  • Microbes act as models for understanding cells.
  • Microbes are used in various industries (food, beverage, chemical, antibiotics) and genetic engineering.
  • Biotechnology uses living organisms to make products.

Microbes as Saprophytes

  • Saprophytes decompose matter into the soil, releasing nutrients (nitrates, phosphates, etc.) back into the environment.
  • Microbes play a crucial role in the nitrogen cycle.

First Microorganisms on Earth

  • Fossils of primitive microorganisms date back about 3.5 billion years.
  • Archaea and cyanobacteria are candidates for the first microorganisms.
  • Infectious diseases have existed as long as humans and animals have been on Earth.

The Marine Microbiome

  • Oceans cover more than 70% of Earth.
  • The marine microbiome includes a vast number of microbes (3 x 10^29 microbes).
  • Viruses are more abundant than bacteria in marine environments.
  • Marine microbes influence life on Earth.

The Soil Microbiome

  • Microbes are associated with plants, soil animals, and the soil itself.
  • Microbes are ubiquitous and are prevalent in soil.
  • Microbes are essential for soil chemistry and soil health.

The Atmospheric Microbiome

  • Air contains between 9,000 and 300,000 microbes per cubic meter.
  • 315 different bacterial species have been identified 10 km in the air.
  • Atmospheric microbes work with marine microbes to contribute to cloud formation.

The Deep Earth Microbiome

  • Microbes are found up to 5 km below the surface and in the deep seafloor.
  • These microbes live in inhospitable environments like extreme heat, no light, and low pH environments.
  • Deep earth microbes may account for a significant proportion of Earth's biomass.

The Human Microbiome

  • The human body contains about 38 trillion microbes, which are 4,000 different species of bacteria and fungi.
  • The number of microbes in the human body is greater than the number of human cells (about 30 trillion).
  • Physical characteristics (like age, diet, and geographic location) play a role in the human microbiome.
  • Newborns are colonized during the birthing process.
  • Some microbes are temporary (transient), while others play different roles:
    • Prevent infection
    • Aid in food breakdown
    • Produce essential nutrients and vitamins
    • Communicate with the brain and immune system
    • Affect obesity, asthma, and allergies

Pioneers in the Science of Microbiology

  • Anton van Leeuwenhoek: The "Father of Microbiology"; made simple microscopes and observed bacteria and protozoa.
  • Louis Pasteur: French chemist who made contributions to microbiology, including discovering the pasteurization process, observing anaerobes, and creating vaccines.
  • Robert Koch: German physician who made significant contributions to microbiology, for the germ theory of disease. Includes methods to fix and stain and cultivate bacteria.

Koch's Postulates

  • Criteria for proving that a microbe causes a particular disease:
    • The microbe must be present in every case of the disease.
    • The microbe can be isolated and cultured.
    • The disease is reproduced when the cultured microbe is introduced into a healthy organism.
    • The microbe is recovered from the experimental host.

Other Notable Scientists of the Golden Age of Microbiology

  • Provided a table that includes the scientists, the year of discovery, specific illnesses, and the contributing agents.

What is an Organism?

  • An organism is any living system consisting of one or more cells.
  • A microorganism is a living system consisting of a microscopic cell with the common features of all living things:
    • Hereditary material
    • Complex biochemical interactions
    • Reproduction
    • Response to stimuli
    • Evolutionary Adaptations
    • Microorganisms can be prokaryotic or eukaryotic and are found in all three domains of life.

The Prokaryotes: Bacteria and Archaea

  • 200,000 prokaryotes, likely millions in nature, have been described.

  • Bacteria are prevalent and are the most studied group in Microbiology.
  • Mostly unicellular but can form filaments.
  • Majority of bacteria are in biofilms.
  • Most prokaryotes have rigid cell walls.
  • Common shapes of prokaryotes include spheres, spirals, and rods.
  • Prokaryotes obtain food from their environment.
  • Some prokaryotes are decomposers, involved with nutrients cycling.
  • Some prokaryotes can photosynthesize.
  • Prokaryotes are also widely studied because they can cause disease.
  • Bacteria cause food spoilage, but many are useful to the food industry.
  • Archaea superficially resemble bacteria but are evolutionarily unique.
  • Many were initially isolated from extreme environments (like Yellowstone hot springs, Dead Sea, and acid mine drainage).
  • No archaea are known to be pathogenic.

The Microbial Eukaryotes: Protists and Fungi

  • Protists include protozoa and single-celled algae.
  • More than 200,000 species.
  • Larger than prokaryotes (10-50 x).
  • May be free-living or associated with plants or animals.
  • Some Algae can perform photosynthesis and have cell walls.
  • Some are clinically important pathogens, such as protozoa.
  • Fungi:
    • 125,000 species, but likely many more.
    • Not photosynthetic, playing a key role as decomposers.
    • Commonly unicellular (yeasts) or multicellular (molds), with filamentous molds.
    • Sources of antibiotics.
    • Responsible for flavors in some foods, like cheese.

Other Infectious Agents: The Viruses

  • Estimated more than 100 million types of viruses.
  • Viruses are acellular and are not considered organisms.
  • Viruses have either DNA or RNA but not both genetic material; they do not have independent metabolic machinery.
  • They have a protein coat around their genetic material.
  • Viruses must infect a host to replicate.
  • Viruses play a crucial role in the evolution of organisms.
  • Only a small fraction of viruses are human pathogens.

Global Mortality from Infectious Diseases

  • Globally, about 15 million deaths occur annually from infectious diseases.
  • Infectious diseases were declared a global emergency several times since 2010 due to the increasing numbers of outbreaks and the severity of some diseases, leading to an increase in death tolls.

Drug-Resistant Pathogens

  • Antibiotic effectiveness is declining due to bacteria evolving resistance. (beneficial mutations, acquisition of resistance genes from other bacteria).
  • Overuse and misuse of antibiotics worsen this issue.
  • Limited availability of new antibiotic drugs.

Emerging and Reemerging Diseases

  • Emerging diseases arise for the first time in a population.
  • 75% to humans from animals
  • 1 or 2 new diseases per year
  • 40 infectious diseases unknown a generation ago.
  • May be due to drug resistance and geographic range expansion
  • Some examples of reemerging diseases as tuberculosis and gonorrhea.

Bioterrorism

  • Intentional use of biological agents as weapons.
  • Agents include bacteria, viruses, and microbial toxins.
  • Bioterror agents can spread rapidly through the air and water.

The Climate Crisis and Infectious Disease

  • Changes in temperature and rainfall patterns affect infectious disease distribution and frequency.
  • Mosquito-borne diseases (e.g., malaria, dengue fever) are impacted by climate change, causing increased fatalities annually.
  • Tropical and subtropical diseases may expand to temperate regions due to climate change.
  • Warmer ocean waters increase the spread of waterborne diseases (cholera, leptospirosis).

The Golden Age of Microbiology

  • Gram staining is a crucial technique for identifying bacteria.
  • Semmelweis, Lister, and Nightingale contributed to infection control and prevention.
  • Early forms of infection control, like handwashing, were vital discoveries.
  • Jenner developed vaccines for illnesses.
  • Ehrlich's work contributed towards the field of chemotherapy

Fields of Microbiology

  • Table 1.3 outlines the many subfields and disciplines of microbiology (basic research, process-centered, applied).

The Modern Age of Microbiology

  • Biochemistry is one basic area of the Modern Age of Microbiology, starting with Pasteur and Buchner.
  • Basic chemical reactions involved in life are further understood by working with microbes.
  • Practical applications in areas like microbiology, gene therapy, and recombinant DNA technology.
  • Many applications are found in the area of cellular function and structure at the molecular level.
  • Understanding the role of microbes in environments (e.g., bioremediation).
  • Exploring how immune systems fight pathogens- areas of applied microbiology (like understanding how certain antibodies and cells function in blood serum), epidemiology, serology, immunology, and chemotherapy.

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Description

Explore the fascinating world of microbes, from bacteria to viruses. Understand the differences between pathogens and non-pathogens, and learn about the microbial communities that affect all life on Earth, including the human microbiome. This quiz will test your knowledge of essential microbiological concepts.

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