Microbiology Exam 1
As discussed in class, what are the 6 current kingdoms?
- Animalia - Plantae - Protista - Fungi - Archaebacteria - Eubacteria
What is a noteworthy aspect of Archaea?
- Archaea and bacteria have different evolutionary histories, as well as significant differences in genetics, metabolic pathways, and the composition of their cell walls and membranes. - Archaea are found in nearly every habitat on earth, even extreme environments that are very cold, very hot, very basic, or very acidic
Why is Bacteria Prokaryotic?
- Are prokaryotic because their genetic material (DNA) is not housed within a true nucleus. - Most bacteria have cell walls that contain peptidoglycan.
What are some common applications of Algae?
- Are protists that can be either unicellular or multicellular and vary widely in size, appearance, and habitat. - Some free living and some in association with plants and animals. - Their cells are surrounded by cell walls made of cellulose, a type of carbohydrate. - Are photosynthetic - Used as biofuels - Agar, derived from seaweed, plays prominent role in microbiology lab
As discussed in class, what are the 3 current domains?
- Bacteria - Archaea - Eukarya Domains Archaea and Bacteria contain all prokaryotic organisms, and Eukarya contains all eukaryotic organisms.
What is a Bacteria?
- Bacteria are found in nearly every habitat on earth, including within and on humans. - Most are harmless or helpful, but some are pathogens, causing disease in humans and other animals. - They have a wide range of metabolic capabilities and can grow in a variety of environments, using different combinations of nutrients; some even photosynthetic - Decomposers, carbon cycle, nitrogen fixation
What did Semmelweiz notice during birthing and the mortality rates of babies between ward handled by med students and midwifery students?
- correlation between putrefaction in autopsy and puerperal sepsis(childbirth fever) - » type of blood poisoning in pregnant women that begins in the uterus and progresses to the abdomen between patients who did not get this fever and the fact that they were not examined by med students. Mortality rates: 29% ward handled by med students 3% ward handled by midwifery students
Does life regenerate itself spontaneously? What is Abiogenesis?
- spontaneous generation - Life springs up from non-living or decaying organic matter - Based on observations of rotting food seemingly producing living organisms
What are the average sizes of animal, bacterial cells and viruses?
Animal Cells - 10 um Bacterial Cells - 1 um Viruses - 0.1 um
What is a Pathogen?
Any microbe that causes disease
What is a microorganism?
Any organism too small to be seen with the naked eye (including bacteria, archaea, fungi, protozoa, algae,viruses)
What does the Germ theory state?
States that diseases may result from microbial infection.
What is Taxonomy?
Taxonomy is the classification, description, identification and naming of living organisms. Classification is the practice of organizing organisms into different groups based on their shared characteristics.
What does the cell theory state?
- All cells only come from other cells (the principle of biogenesis). - Cells are the fundamental units of organisms
What kind of information would I look up in Bergey's manual?
- Bergey's Manual of Determinative Bacteriology and Bergey's Manual of Systematic Bacteriology are the standard references for identifying and classifying different prokaryotes - Biochemical tests, DNA/RNA sequencing, serological tests
How are protozoa classified?
- Distinguished by their diverse locomotion: cilia, flagella, pseudopods, - Some are photosynthetic - Free living or parasitic - Some pathogens
What were the main contributions of Antony Van Leeuwenhoek to the field of microscopy?
- Dutch cloth merchant - considered the father of microbiology - was the first to develop a lens powerful enough to view microbes - is credited as the first person to observe (including bacteria, yeast and protists) which he called "animalcules" and "wee little beasties" - was also first to record microscopic observations of muscle fibers banded pattern, spermatozoa and blood flow in capillaries
What were the main contributions of Zachariah Janssen to the field of microscopy?
- Dutch spectacle maker, along with his dad, Hans, credited with first simple, microscope, compound microscope and telescope
What were the main contributions of Robert Hooke to the field of microscopy?
- English scientist, improved on compound microscope (coarse and fine adjustment, specimen holder, illuminator)
What was Joseph Lister's solution to the issue of deaths from postoperative infections?
- English surgeon - 1860 Noticed patients dying from postoperative infections - Using data gathered in operating rooms and from old bandages he picked up in the trash outside hospitals, proposed that surgical infections were due to substances in the air. - Used carbolic acid to wrap wounds and around the air - Led to antisepsis
Explain how the experiments of Francisco Redi and Louis Pasteur disproved the theory. How did these experiments differ from each other?
- Francesco Redi's experimental setup consisted of an open container, a container sealed with a cork top, and a container covered in mesh that let in air but not flies. Maggots only appeared on the meat in the open container. However, maggots were also found on the gauze of the gauze-covered container. Showed that only the open jar which flies could access produced maggots. Thus, decaying meat does not spontaneously produce maggots. Due to the simplicity of the experiment, people began to doubt spontaneous generation.
What were the main contributions of Louis Pasteur during this time?
- French chemist - is credited with numerous innovations that advanced the fields of microbiology and immunology - showed that individual microbial strains had unique properties - demonstrated that fermentation is caused by microorganisms - invented pasteurization, a process used to kill microorganisms responsible for spoilage - developed attenuation principle (basis of vaccines) for the treatment of diseases, including rabies and cholera in animals and humans.
What were the main contributions of Robert Koch during this time?
- German Physician - was the first to demonstrate the connection between a single isolated microbe and a known human disease (one microbe one disease- Koch postulates). - identified the specific microbes that causes anthrax, cholera and tuberculosis - awarded the Nobel Prize in Medicine or Physiology in 1905
What were the main contributions of Ernst Haeckel to the field of taxonomy?
- German biologist, philosopher and physician - Proposed a four kingdom model of taxonomy including two additional kingdoms, Protista and Monera
How has the phylogeny tree changed in the field of taxonomy in the late 20th century?
- Haeckel's and Whittaker's trees presented hypotheses about the phylogeny of different organisms based on readily observable characteristics. - But the advent of molecular genetics in the late 20th century revealed other ways to organize phylogenetic trees. Modern taxonomy relies heavily on comparing the nucleic acids or proteins from different organisms.
What were the main contributions of Carl Woese to the field of taxonomy?
- In the 1970s, American microbiologist Carl Woese and his collaborator George Fox created a genetics-based tree of life based on similarities and differences they observed in the gene sequences coding for small subunit rRNA of different organisms. - created a tree with three Domains above the level of Kingdom: Archaea, Bacteria, and Eukarya (Protista, Plantae, Fungi, Animalia)
How was John Snow able to pinpoint the source of a cholera outbreak in 1848?
- John Snow - English surgeon - 1848-1849 As cholera spread, Snow analyzed the death records attributed to cholera, - gathered information about the victims, and interviewed survivors in the neighborhood. - Produced a map plotting all the cholera cases in the London Soho district and observed a cluster near to the Broad Street pump. - When the pump's handle was removed, the number of cholera cases dropped significantly. - First case of public case measure to interrupt disease transmission - predicted mode of transmission of cholera: waterborne
How do we write the name of an organism using the binomial system?
- Linnaeus developed system to identify organisms by genus and species. - Both names italicized, only genus capitalized - Ex: Escherichia coli - The abbreviated form is simply the first initial of the genus, followed by a period and the full name of the species. - Ex: E. coli
How did Ignaz Semmelweis resolve the maternal mortality rates?
- Med students had spent mornings dissecting cadavers. - Deducted that med students were transferring disease - Ordered the med students to wash their hands with chloride of lime before entering the delivery room - Mortality rate - 2%
What are some subfields of Microbiology?
- Microbiology is a broad term that encompasses the study of all different types of microorganisms. - Bacteriology is the study of bacteria - Mycology is the study of fungi - Protozoology is the study of protozoa - Parasitology is the study of helminths and other parasites - Virology is the study of viruses. - Immunology, is the study of the immune system, is often included in the study of microbiology because host-pathogen interactions are central to our understanding of infectious disease processes. - Microbiologists can also specialize in certain areas of microbiology, such as clinical microbiology, environmental microbiology, applied microbiology, or food microbiology.
Reminder : Viruses do not fall within any of the three domains of life.
- Microorganisms differ from each other not only in size, but also in structure, habitat, metabolism, and many other characteristics. - Unicellular, multicellular, and acellular - Microorganisms are found in each of the three domains of life: Archaea, Bacteria, and Eukarya.
What are Helminths?
- Multicellular parasitic worms - fall within the field of microbiology because diseases caused by helminths involve microscopic eggs and larvae. - Nematodes, cestodes, trematodes - Ex: guinea worm, or Dracunculus medinensis
What is Mold?
- Multinucleated - Molds are made up of long filaments that form visible colonies . - Molds are found in many different environments, from soil to rotting food to dank bathroom corners. - Molds play a critical role in the decomposition of dead plants and animals. - Some molds can cause allergies, and others produce disease-causing metabolites called mycotoxins. - Molds have been used to make pharmaceuticals, including penicillin, which is one of the most commonly prescribed antibiotics, and cyclosporine, used to prevent organ rejection following a transplant.
Why study microbiology? 3 reasons?
- No living creature can separate itself from interaction with microbes - We use them to help create pharmaceuticals, clean up hazardous waste, and make food products. - Some cause infection and disease.
What were the main contributions of Robert Whitaker to the field of taxonomy?
- Proposed a five kingdom tree model, adding fungi - Proposed the empire or superkingdom tree level - a level of categorization above the kingdom level - to distinguish between organisms that have membrane-bound nuclei in their cells (eukaryotes) and those that do not (prokaryotes) - Empire Prokaryota contained Kingdom Monera - Empire Eukaryota contained Fungi, Protista, Plantae and Animalia
What was Florence Nightingale's major contribution to the field of epidemiology?
- Recorded statistics on epidemic typhus in the English civilian and military populations. - 1858 Published a 1000 page report using statistical comparisons to demonstrate that diseases, poor food, and unsanitary conditions were killing soldiers. - Her work resulted in reforms in the British Army and she became the first female member to the Statistical Society.
What was Robert Hooke's important discovery when observing cork under the microscope?
- Robert Hooke (1635-1703) - English scientist - First to draw microorganisms - Published Micrographia - Coined term "cells"(from cork)
Who was William Halsteu?
- Surgeon at John Hopskin - Invented Latex Gloves
What are some unique characteristics of Fungi?
- There are more than 1000 known species - Most grow best in warm, moist places - decomposers ; are not photosynthetic - Their cell walls are usually made out of chitin - Provide antibiotics - Have unicellular (yeast) or multinucleated (mold) forms
What is Yeast?
- Unicellular - Yeasts are found in many different environments, from the deep sea to the human navel. - Some yeasts have beneficial uses, such as causing bread to rise and beverages to ferment; but yeasts can also cause food to spoil. - Some cause disease like vaginal yeast infections and oral thrush.
What makes up the structure of a virus? Why are viruses not considered alive?
- Viruses are acellular microorganisms are not composed of cells - Cannot grow in pure culture - Consists of core of genetic material—either DNA or RNA—surrounded by a protein coat - Differ by shape, size, and genetic material - By incorporating themselves into a host cell, viruses are able to take over the host's cellular mechanisms to multiply and infect other hosts. - Viruses can infect all types of cells, from human cells to the cells of other microorganisms. - In humans, viruses are responsible for numerous diseases, from the common cold to deadly Ebola
What is a phylogenetic tree?
- With advances in technology, other scientists gradually made refinements to the Linnaean system and eventually created new systems for classifying organisms. - In the 1800s, there was a growing interest in developing taxonomies that took into account the evolutionary relationships, or phylogenies, of all different species of organisms on earth. - One way to depict these relationships is via a diagram called a phylogenetic tree (or tree of life). In these diagrams, groups of organisms are arranged by how closely related they are thought to be. - Linnaeus' tree of life contained just two main branches for all living things: the animal and plant kingdoms.
What were the main contributions of Carolus Linnaeus to the field of taxonomy?
-Swedish botanist, zoologist and physician - developed a system for categorizing plants and animals - Linnaean taxonomy proposed in Systema Naturae - Linnaeus divided the natural world into three kingdoms: animal, plant, and mineral (the mineral kingdom was later abandoned) - The names of the levels in Linnaeus's original taxonomy were kingdom, class, order, family, genus, (plural: genera) and species - Developed binomial nomenclature for identifying organisms
What are some exceptions to Koch's postulates?
1) Microbe not always isolated outside the body •Virulent strains of Treponema pallidum (syphilis) never cultured on artificial media. •Mycobacterium leprae has never been grown on artificial media •Legionnaire's disease: inoculate victim's lung tissue into guineas pigs and then culture diseased guinea pig tissue into yolk sacs of chick embryos. 2) Some pathogens cause many diseases •Streptococcus pyogenes sore throat, skin infections, scarlet fever 3) Some agents that cause disease in humans have no other hosts •HIV: ethical dilemma of intentionally inoculating humans with infectious agents
What is the limitation of the human eye?
100 micrometers (um) is limitation of naked eye
What was the sewer the Romans built?
600 BC in Rome, they built aqueducts, which brought fresh water into the city, and a giant sewer, the Cloaca Maxima or "Greatest Sewer" which carried waste away and into the river tiber.
What is the significance of the attenuation principle?
Developed attenuation principle (basis of vaccines) for the treatment of diseases, including rabies and cholera in animals and humans
What is a infectious disease?
Disease resulting from the presence and activity of a microorganism
As discussed in class, what are the eight taxonomic ranks in order from highest to lowest?
Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species
What happened during Louis Pasteur's experiment?
Each experiment begins with sterilized broth. Any living things the broth may have contained have been destroyed by heat. With one flask open to air and the other flask sealed. The broth provides nutrients for the growth of unseen organisms in the air, life comes from other life. In open flask organisms appear and in closed flask no organisms appear. The critics believe sealing the flask prevents entry of the "life force" needed for spontaneous generation. Pasteur then invented the swan neck flask that will allow the "life force" in but will trap dust and microorganisms. "Life force" reaches broth but is free from any organisms because microorganisms are trapped in neck of flask. Pasteur has disproven spontaneous generation.
How did Hippocrates contribute to the early notions of disease?
Hippocrates was a Greek Physician and considered the "father of western medicine" Believed that disease had natural causes from within patients or their environments and not supernatural - first to prescribe medicine (willow bark) to patients - made oldest surviving medical book Hippocrates Corpus and Hippocrates oaths for medical students
What was the key finding of Ignaz Semmelweis during his inquiry into the births at Vienna General Hospital?
Semmelweis and blood poisoning - Ignaz Semmelweis- - Hungarian obstetrician - Between 1846 and 1848, meticulously recorded the number of births and maternal deaths at Vienna General hospital - Mortality rate- 13-18% in delivering mothers
What are Protists?
Includes Algae and Protozoa
How did Marcus Terentius Varro contribute to the early notions of disease?
Marcus Terentius Varro was a prolific Roman writer. Was one of the first people to propose the concept that things we cannot see can cause disease. Proposed that disease could be caused by "certain minute creatures... which cannot be seen by the eye".
Regarding the Golden Age of Microbiology, what two scientists that we discussed were pivotal in advancing our understanding of the unseen world?
The Golden Age of Microbiology spawned a host of new discoveries between 1857 and 1914. Two famous microbiologists, Louis Pasteur and Robert Koch, were especially active in advancing our understanding of the unseen world of microbes.
How did early civilizations handle the correlation between sewage and disease?
The ancient Greeks attributed disease to bad air "mal'aria" which they called "miasmatic odors" The Romans also believed in the miasma hypothesis and created a complex sanitation infrastructure to deal with sewage
What are the common shapes of Bacteria?
They are often described in terms of their general shape. Common shapes include spherical (coccus), rod-shaped (bacillus), or curved (spirillum, spirochete, or vibrio).
How did Thucydides contribute to the early notions of disease?
Thucydides was a Greek philosopher and historian and is considered the father of scientific history because he advocated for evidence based analysis of cause and effect reasoning. Observed that survivors of the Athenian plague were subsequently immune to the infection
What are the four Koch's postulates?
•German country doctor (1843-1910) •1875 Koch injected mice with blood from anthrax victimized sheep/cattle. To prove a microorganism causes disease. 1) Identical microbe must be present in all individuals with the same disease, but not in healthy ones. 2) Microbe must be cultured outside the body. 3) Microbe must induce disease when given to a healthy individual of the same species. 4) Identical microbe must be reisolated from the experimentally infected organism.
What is the modern focus of the germ theory of disease?
•Today •No longer just about finding the germ associated with a disease. •Now interested in the mechanisms of microbial agents. •New diseases popping out all the time and one disease may be associated with multiple organisms. •Antibiotic resistance