Microbiology Quiz - Key Concepts & Figures

General Microbiology Course Information

Course name: General Microbiology
Institution: Technological University of the Philippines

Introduction to Microbiology

This is the introductory section of the course.

Pre-Assessment Questions

What is the name for bacteria that require oxygen to grow?
Who developed the taxonomic system for grouping similar organisms?
What theory proposes that organisms do not descend from other organisms or a parent, and only require specific environmental conditions for creation?
Who is considered the "father of (classical) microbiology"?
Who proposed the theory of spontaneous generation?
Who is considered the "father of modern microbiology"?

Historical Figures in Microbiology

Robert Hooke (1635-1703)
Antonie van Leeuwenhoek (1632-1723)
Lord Joseph Lister (1827-1912)
Edward Jenner (1749-1823)
Louis Pasteur (1822-1895)
Robert Koch (1843-1910)
Paul Ehrlich (1854-1915)
Alexander Fleming (1881-1955)
and others...

The Early Years of Microbiology

What does life really look like?
- Antoni van Leeuwenhoek (Dutch)
  - Created and used simple microscopes.
  - Often constructed a new microscope for each specimen.
  - Observed tiny animals, fungi, algae, and single-celled protozoa (animalcules).
  - By the end of the 19th century, these were called microorganisms.
How can microbes be classified?
- Carolus Linnaeus developed a taxonomic system for grouping similar organisms together.
- Leeuwenhoek's microorganisms were grouped into six categories:
  - Bacteria
  - Archaea
  - Fungi
  - Protozoa
  - Algae
  - Small multicellular animals
Bacteria and Archaea
- Unicellular
- Lack nuclei
- Much smaller than eukaryotes
- Found everywhere with sufficient moisture
- Reproduce asexually
- Two kinds:
  - Bacteria — cell walls contain peptidoglycan
  - Archaea — cell walls composed of polymers other than peptidoglycan
Fungi
- Eukaryotic (membrane-bound nucleus)
- Obtain food from other organisms
- Possess cell walls
- Include:
  - Molds — multicellular; grow as long filaments; reproduce by sexual and asexual spores.
  - Yeasts — unicellular; reproduce by budding or sexual spores.
Protozoa
- Single-celled eukaryotes
- Similar to animals in nutrient needs and cellular structure
- Live freely in water; some live in animal hosts
- Asexual (most) and sexual reproduction
- Most capable of locomotion by:
  - Pseudopodia
  - Cilia
  - Flagella
Algae
- Unicellular or multicellular
- Photosynthetic
- Simple reproductive structures
- Categorized based on pigmentation, storage products, and cell wall composition

The Golden Age of Microbiology

Scientists searched for answers to four questions:
- Is spontaneous generation of microbial life possible?
- What causes fermentation?
- What causes disease?
- How can we prevent infection and disease?
Redi's Experiments
- Decaying meat isolated from flies, no maggots developed.
- Meat exposed to flies, maggots developed.
- Scientists began to doubt Aristotle's theory.
Needham's Experiments
- Scientists thought microbes could arise spontaneously but not animals.
Spallanzani's Experiments
- Concluded spontaneous generation does not occur.
- Critics argued against experiments because sealed vials disallowed enough air for organisms to survive.
Pasteur's Experiments
- Used “swan-necked” flasks
- Microbial growth appeared only when the flask was tilted, dust from the bend in the neck seeped back into the flask causing cloudiness with microbes within a day
- Proved that spontaneous generation does not occur
The Scientific Method
- Observation leads to a question.
- Question generates hypothesis.
- Hypothesis is tested through experiment(s).
- Results prove or disprove hypothesis; modify or accept hypothesis.
- Accepted hypothesis leads to theory/law.
What causes fermentation?
- Spoiled wine threatened vintners' livelihoods. Some believed air caused fermentation. Others insisted that living organisms caused fermentation.
- Pasteur's experiment demonstrated that microorganisms cause fermentation.
What causes disease?
- Pasteur developed the germ theory of disease.
- Koch studied causative agents of disease, including anthrax and examining colonies of microorganisms.
Koch's Postulates
- Suspected causative agent must be found in every case of the disease and be absent from healthy hosts.
- Agent must be isolated and grown outside the host.
- When the agent is introduced into a healthy, susceptible host, the host must get the disease.
- The same agent must be found in the diseased experimental host.
Gram's Stain
- Hans Christian Gram developed a staining technique in 1884.
- Involved applying dyes.
- Separates microbes into Gram-positive and Gram-negative groups.
How can we prevent infection and disease?
- Semmelweis and handwashing
- Lister's antiseptic technique
- Nightingale and nursing
- Snow – infection control and epidemiology
- Jenner's vaccine – field of immunology
- Ehrlich's "magic bullets" – field of chemotherapy

The Modern Age of Microbiology

What are the basic chemical reactions of life?
- Biochemistry began with Pasteur's and Buchner's works, using microbes as model systems for biochemical reactions.
- Practical applications include designing herbicides and pesticides, diagnosing illness, monitoring responses to treatment, and treating metabolic diseases.
How do genes work?
- Microbial genetics, molecular biology, recombinant DNA technology, and gene therapy
Microbial Genetics
- Avery, MacLeod, and McCarty discovered genes are contained in DNA molecules.
- Beadle and Tatum proposed a connection between gene activity and protein function.
Molecular Biology
- Explanation of cell function at the molecular level.
- Pauling's proposal that gene sequences could provide understanding of evolutionary relationships/processes.
- Identification of microbes that have never been cultured.
- Woese's determination of cell groupings (bacteria, archaea, eukaryotes).
Recombinant DNA Technology
- Manipulation of genes in microbes, plants, and animals for practical applications.
- Production of human blood-clotting factor using E. coli to aid hemophiliacs.
Gene Therapy
- Inserting a missing gene or repairing a defective one in humans by inserting desired genes into host cells.
What roles do microorganisms play in the environment?
- Bioremediation uses living bacteria, fungi, and algae to detoxify polluted environments.
- Recycling of chemicals like carbon, nitrogen, and sulfur.
How do we defend against disease?
- Serology – study of blood serum, blood contains chemicals and cells that fight infection.
- Immunology – study of the body's defense against specific pathogens, chemotherapy, Fleming discovered penicillin, and Domagk discovered sulfa drugs

Other Information

Activity No. 1 & 2: Microbiology activity involving concept mapping, student's expected to create a concept map, and brief explanation on historical development of microbiology.
Sources : Provide citations from research papers, YouTube videos, other sources for the course content.