113 Questions
What is the basic unit of length?
Nanometer (nm)
Which microscope can magnify objects in excess of 100,000x?
Electron Microscope
What physical phenomenon causes light rays to change direction due to a change in the medium through which they travel?
Refraction
What is the equivalent of 10^(-6) meter in micrometers (µm)?
1 µm
Which bacterial shapes are mentioned as the most common?
Coccus and Rod
What is the critical permeability barrier between the bacterial cell and the external environment?
Cytoplasmic membrane
Which staining technique is important in distinguishing between bacterial cell wall types?
Gram stain
What prevents cell lysis and distinguishes between Gram-positive and Gram-negative bacteria?
Cell wall
What are the examples of bacterial shapes mentioned in the text?
Vibrio, Spirillum, Spirochete
What are the structural features of bacteria mentioned in the text?
Pilus, Ribosomes, Cell wall
What is the directed movement of molecules across cytoplasmic membranes using?
Transport systems
What is the lipid bilayer's role in bacterial cells?
Permeability
What distinguishes between Gram-positive and Gram-negative bacteria?
Cell wall structure
What is the purpose of the protein secretion system in bacterial cells?
Transport proteins out of the cell
What is the role of the capsule in bacterial cells?
Protection
What is the function of the pilus in bacterial cells?
Adherence to surfaces
What distinguishes major bacteria types based on their cell envelope structure?
Gram stain
Which type of cell envelope has a unique lipid bilayer and thin peptidoglycan layer?
Gram-negative
What prevents dye washout in Gram-positive cells during the Gram stain?
Crystal violet
Which type of bacteria requires the acid-fast stain due to a waxy coat that repels the Gram stain?
Mycobacterium
What is the main component used to distinguish bacterial cell envelope architecture into Gram-positive and Gram-negative types?
Peptidoglycan
What are glycan chains cross-linked via to create peptidoglycan?
Tetrapeptide chains
What do peptidoglycan subunits comprise?
NAG and NAM sugars, and wall peptides with unique D-amino acids
Which type of cell wall has a thick peptidoglycan layer with teichoic acids and is permeable?
Gram-positive
What function do teichoic acids in Gram-positive cells serve?
Negatively charged and function as a cation reservoir and in cell wall construction
What is the importance of the bacterial cell envelope?
Bacterial classification and role in cell division
What is the bacterial cell wall peptidoglycan made from?
Subunits made of sugar and peptides, forming a large molecular net that covers the entire cell
What is the rigid cell wall component made from N-acetylmuramic acid and N-acetylglucosamine?
Peptidoglycan
What does magnification refer to in microscopy?
The increase in the apparent size of an object compared to its actual size
What is the main function of immersion oil in a bright-field microscope?
To displace air, prevent light from missing the objective lens, and match the refractive index of the glass
What is the resolving power of a bright-field microscope limited to?
0.2µm
What type of microscopes use electromagnetic lenses and electrons?
Electron microscopes
How do dark-field microscopes allow cells to appear bright against a dark background?
By directing light towards the specimen at an angle
What is the primary reason for the eradication of smallpox being considered a major public health success?
Development of a highly effective vaccine and a WHO-organized widespread vaccination campaign
What has been a significant outcome of the 'Golden Age of Microbiology'?
Development of vaccines, discovery of antibiotics, and reduced mortality/morbidity due to infectious diseases
What was the leading cause of death globally in 1900?
Infectious disease
What distinguishes Ebola virus disease from other infectious diseases mentioned in the text?
Regular outbreaks since its discovery
What is the study of organisms too small to be seen without a microscope called?
Microbiology
Where are microbes found?
Everywhere, including extreme environments and the human body
What is the primary role of most microorganisms?
Not harmful and necessary for life, playing roles in decomposition and carbon cycling
What is the essential role of microbes in maintaining oxygen levels and the nitrogen cycle?
Crucial for agriculture and life as we know it
In what ways are microbes utilized in various industries?
Food production, biotechnology, and the synthesis of commercially valuable chemicals
What is the term for the process of cleaning up environmental pollutants using microbes?
Bioremediation
Who has been developing microbes for bioremediation to destroy or detoxify industrial chemicals at contaminated sites?
Dr. Elizabeth Edwards
What is a major global public health threat due to strains of bacteria and fungi resistant to treatment?
Antibiotic resistance
What factor increases the likelihood of emerging and re-emerging diseases?
Modern lifestyles
What leads to disparities in diseases like tuberculosis within countries?
Social differences
Which disease outbreak led to travel advisories issued by the World Health Organization in 2002-2003?
SARS
How did Ryan White, an early victim of AIDS, contract HIV?
Through a blood transfusion
What did Louis Pasteur's experiments in 1861 disprove?
Spontaneous generation of microbes
Which domain branches off from Archaea in the 'tree of life'?
Eukarya
What are Prions?
Infectious proteins causing normal proteins to misfold
What did Robert Koch develop to identify the causative agents of diseases?
Postulates
Which theory attributed diseases like cholera and malaria to poisonous emanations from putrefying carcasses, rotting vegetation, and molds?
Miasma Theory of Disease
Which domain of the 'tree of life' includes living organisms and non-living infectious agents?
Viruses
What did the acceptance of the Germ Theory of Disease aid?
The development of postulates to identify disease-causing agents
What are Viruses?
Obligate intracellular parasites
What did the Turkish scientist Akshamsaddin propose as the cause of diseases?
Concept of 'invisible seeds'
What did pioneers like Semmelweis and Lister infer contributed to mortality rates?
Non-hygienic practices
What are Eukaryotic organisms studied by microbiologists?
Fungi, Algae, Protozoa, and Helminths
What did the Jain scriptures describe?
Sub-microscopic creatures
Which domain of microbes is recognized as distinct from bacteria and can live in extreme conditions?
Archaea
Which type of cells have a true nucleus and membrane-bound organelles, making them more complex than archaeal or bacterial cells?
Eukaryotic cells
Which organism can transform Perchloroethene (PCE) into harmless ethene?
Dehalococcoides bacteria
What did DNA technology revolutionize in the classification of microbes?
Classification of organisms
Which type of organisms are the most abundant cellular and acellular organisms?
Bacteria
What is the study of disease-causing microbes known as?
Medical microbiology
What is the classification of microbes crucial for understanding?
Impact on human health, the environment, and various industrial processes
Which type of cells can be microscopic or macroscopic, single-celled or multicellular, and degrade organic material with their rigid cell wall?
Fungi
What is the classification of microbes essential for understanding the impact on?
The planet's creation and current function
What is the role of Prokaryotes, such as bacteria and archaea, in the classification of microbes?
They are single-celled organisms without membrane-bound organelles
What did Carl Linnaeus and Ernst Haeckel contribute to the classification of organisms?
Contributed to the classification of microbes
Which domain of microbes is more complex than Archaeal or Bacterial cells?
Eucarya
What is the primary reason for the eradication of smallpox being considered a major public health success?
Widespread vaccination campaign organized by WHO
What did the 'Golden Age of Microbiology' lead to?
Development of vaccines and discovery of antibiotics
What was the leading cause of death globally in 1900?
Infectious disease
What is the main component used to distinguish bacterial cell envelope architecture into Gram-positive and Gram-negative types?
Peptidoglycan layer
Which theory of disease was prevalent from ancient Greece to the mid-19th century?
Miasma Theory of Disease
Who developed postulates to identify the causative agents of diseases, contributing to the acceptance of the Germ Theory?
Robert Koch
What is the primary role of most microorganisms?
Contributing to the decomposition and carbon cycling
What are Prions?
Infectious proteins
What is the study of organisms too small to be seen without a microscope called?
Microbiology
Which domain branches off from Archaea in the 'tree of life'?
Eukarya
What did Dr. Elizabeth Edwards develop microbes for?
Bioremediation of environmental pollutants
What did Louis Pasteur's experiments in 1861 disprove?
Spontaneous Generation of Microbes
What is the impact of modern lifestyles on the likelihood of emerging and re-emerging diseases?
Increases the likelihood
What are the two domains included in the 'tree of life'?
Archaea and Eukarya
What is the major global public health threat related to antibiotic resistance?
Strains of bacteria and fungi resistant to treatment
What is the role of microbes in maintaining oxygen levels and the nitrogen cycle?
They are essential for maintaining oxygen levels and the nitrogen cycle
What did the prevalent Miasma Theory of Disease attribute diseases to?
Poisonous emanations
Where are microbes found?
Everywhere, including extreme environments and on the human body
What is the role of Prions in cellular dysfunction?
Leading to misfolding of normal proteins
What did scholars prior to the ability to observe microbes suggest?
Existence of invisible seeds
What is the primary use of microbes in bioremediation?
Cleaning up environmental pollutants
Which of the following is a characteristic of Eukaryotic organisms studied by microbiologists?
Significant diversity
What is the impact of significant health outcome gaps within countries?
Leads to disparities in diseases like tuberculosis
What are Viruses?
Obligate intracellular parasites
What is the primary impact of microbes on agriculture?
They are crucial for agriculture and life as we know it
What is the role of most microorganisms in the environment?
Contributing to the decomposition and carbon cycling
What was the role of Jain scriptures regarding microbes?
Describing sub-microscopic creatures
What is the primary use of microbes in food production?
Fermentation and preservation processes
What is the classification of microbes crucial for understanding?
Their impact on human health, the environment, and various industrial processes
What distinguishes Eukaryotic cells from Archaeal or Bacterial cells?
Having a true nucleus and membrane-bound organelles
What did DNA technology revolutionize in the classification of microbes?
The identification and categorization of microbes
What is the primary role of Prokaryotes, such as bacteria and archaea, in the classification of microbes?
Having different cell wall compositions
Which domain of microbes is recognized as distinct from bacteria and can live in extreme conditions?
Archaea
What is the importance of the bacterial cell envelope?
It acts as a critical permeability barrier between the bacterial cell and the external environment
What are the examples of bacterial shapes mentioned in the text?
Cocci, bacilli, spirilla
What is the function of Fungi, including Aspergillus, mentioned in the text?
Degrading organic material with their rigid cell wall
What did Carl Linnaeus and Ernst Haeckel contribute to the classification of organisms?
Contributed to the development of the three-domain system
What is the role of Perchloroethene (PCE) or 'PERC' in the context of microbes?
It can be transformed into harmless ethene by Dehalococcoides bacteria
What is the study of microbes and their classification crucial for understanding?
Their impact on human health, the environment, and various industrial processes
What did Medical microbiology primarily study?
Disease-causing microbes
Study Notes
Microscopy Principles
- Refractive index measures the relative speed of light passing through a medium like air or water.
- Lenses use refraction to focus light by bending it based on the principles of refraction.
- Magnification is the increase in the apparent size of an object compared to its actual size, with "100,000x" meaning the image appears 100,000 times larger.
- Resolution is the ability to see distinct objects instead of a blur, with poor resolution resulting in objects appearing as a single blur when magnified.
- Contrast is the ability to see objects against the background, with low contrast resulting in poor visibility against the background.
- Bright-field microscopes are the most common in laboratories and use a series of magnifying lenses to evenly illuminate the entire field of view.
- Compound microscopes have ocular (10x) and objective (4x, 10x, 40x, 100x) lenses, with the total magnification being the product of the magnifying power of the ocular and objective lenses.
- The resolution for a bright-field microscope is limited to 0.2µm, preventing the viewing of virus details.
- Immersion oil is used with the 100x lens on a bright-field microscope to displace air, prevent light from missing the objective lens, and match the refractive index of the glass.
- Dark-field microscopes direct light towards the specimen at an angle, allowing cells to stand out as bright against a dark background.
- Electron microscopes use electromagnetic lenses, electrons, and a fluorescent screen to replace glass lenses, visible light, and the eye, with a resolving power ~1,000-fold greater than bright-field microscopes.
- The wavelength of electrons is ~1,000 times shorter than light, enabling electron microscopes to achieve a resolving power of ~0.3 nm.
Microbiology and Classification of Microbes
- Perchloroethene (PCE) or "PERC" is a dry cleaning solvent that can be transformed into harmless ethene by Dehalococcoides bacteria.
- Medical microbiology studies disease-causing microbes, with only a small fraction of microbes causing disease, and past epidemics significantly impacting human civilization.
- Microbes are diverse and ancient organisms, essential to the planet's creation and current function, and are the most abundant cellular (bacteria) and acellular (viruses) organisms.
- Microbes are classified into domains: Bacteria, Archaea, and Eucarya, with Eukaryotes being more complex than Archaeal or Bacterial cells.
- Carl Linnaeus and Ernst Haeckel contributed to the classification of organisms, with DNA technology revolutionizing the classification of microbes.
- The classification of microbes includes infectious agents (non-living) and organisms (living) within the domains Bacteria, Archaea, Viruses, and Eucarya.
- Prokaryotes, such as bacteria and archaea, are single-celled organisms without membrane-bound organelles and have different cell wall compositions.
- Archaea, recognized as distinct from bacteria in 1977, can live in extreme conditions (extremophiles) and are part of the microbiota of all organisms.
- Eukaryotic cells have a true nucleus and membrane-bound organelles, making them more complex than archaeal or bacterial cells.
- Fungi, including Aspergillus, can be microscopic or macroscopic, single-celled or multicellular, and degrade organic material with their rigid cell wall.
- The study of microbes and their classification is crucial for understanding their impact on human health, the environment, and various industrial processes.
- Understanding the diversity and characteristics of microbes can lead to the development of innovative solutions in healthcare, biotechnology, and environmental protection.
Microbiology and Classification of Microbes
- Perchloroethene (PCE) or "PERC" is a dry cleaning solvent that can be transformed into harmless ethene by Dehalococcoides bacteria.
- Medical microbiology studies disease-causing microbes, with only a small fraction of microbes causing disease, and past epidemics significantly impacting human civilization.
- Microbes are diverse and ancient organisms, essential to the planet's creation and current function, and are the most abundant cellular (bacteria) and acellular (viruses) organisms.
- Microbes are classified into domains: Bacteria, Archaea, and Eucarya, with Eukaryotes being more complex than Archaeal or Bacterial cells.
- Carl Linnaeus and Ernst Haeckel contributed to the classification of organisms, with DNA technology revolutionizing the classification of microbes.
- The classification of microbes includes infectious agents (non-living) and organisms (living) within the domains Bacteria, Archaea, Viruses, and Eucarya.
- Prokaryotes, such as bacteria and archaea, are single-celled organisms without membrane-bound organelles and have different cell wall compositions.
- Archaea, recognized as distinct from bacteria in 1977, can live in extreme conditions (extremophiles) and are part of the microbiota of all organisms.
- Eukaryotic cells have a true nucleus and membrane-bound organelles, making them more complex than archaeal or bacterial cells.
- Fungi, including Aspergillus, can be microscopic or macroscopic, single-celled or multicellular, and degrade organic material with their rigid cell wall.
- The study of microbes and their classification is crucial for understanding their impact on human health, the environment, and various industrial processes.
- Understanding the diversity and characteristics of microbes can lead to the development of innovative solutions in healthcare, biotechnology, and environmental protection.
Test your knowledge of microscopy principles with this quiz! Learn about refractive index, magnification, resolution, and different types of microscopes, from bright-field to electron microscopes.
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