Ch. 1 History of Microbiology Flashcards
list six reasons why microorganisms are important
- most populous and diverse group of organisms
- found everywhere on the planet
- play a mjor role in recycling essential elements
- source of nutrients and some carry out photosynthesis
- benefit society by production of food, beverages, antibiotics, and vitamins
- some cause disease in plants and animals
what defines a member of the microbial world?
organisms and acellular entities too small to be clearly seen by unaided eye
how large are MOST microorganisms?
less than 1mm, but some can be macroscopic
are microbes usually simple or complex?
relatively simple in their construction and lack highly differentiated cells and distinct tissues
what are the two types of microbes?
cellular and acellular
list 4 types of cellular microbes and give an example of each
- fungi: yeast molds
- protists: algae, protozoa, slime molds
- bacteria: E. coli
- archaea: mathanogens
list 4 types of acellular microbes and what they are composed of
- viruses: protein and nucleic acid
- viroids: RNA
- satellites: nucleic acid, often RNA
- prions: protein
list the 2 types of microbial cells
- prokaryotic
2. eukaryotic
define prokaryotic cells
lack a membrane-delimited nucleus
define eukaryotic cells
have a true membrane-enclosed nucleus, are more morphologically complex and are usually larger than prokaryotic cells
describe the classification scheme of microorganisms
3-domain system based on a comparison of ribosomal RNA genes
what are the 3 classifications of microorganisms
- bacteria (true bacteria)
- archaea
- eukarya (eukaryotes)
decribe domain bacteria (4)
- usually single-celled
- majority have a cell wall with peptidoglycan
- most lack a membrane-bound nucleus
- ubiquitous and SOME live in extreme environments
what distinguishes domain archaea from domain bacteria
unique RNA gene sequences
describe domain archaea (4)
- LACK peptidoglycan in cell walls
- have unique membrane lipids
- some have unusual metabolic characteristics
- many live in extreme environments
give 2 members of domain eukarya
- protists
2. fungi
describe the general size of protists
generally larger than bacteria and archaea
list 4 protists and give a feature of each
- algae: photosynthetic
- protozoa: may be motile “hunters, grazers”
- slime molds: 2 life cycle stages
- water molds: devastating diseases in plants
list 2 fungi and their amount of cells (general)
- yeath: unicellular
2. mold: multicellular
what do acellular infectious agents need to survive and live
a host
list 3 acellular infectious organisms
- viruses
- viroids and virusoids
- prions
what is the smallest of all microbes?
viruses
what do viruses require to replicate?
host cell
what do viruses cause?
a range of diseases and some cancers
what are viroids and virusoids?
infectious agents composed of RNA
what are prions?
infectious proteins
what did Antony von Leeuwenhoek do?
was the first person to observe and describe microorganisms accurately
what is spontaneous generation?
the idea that living organisms can develop from nonliving or decomposing matter
what did Francesco Redi do?
discredited spontaneous generation by showing that maggots on decaying meat came from fly eggs (covered and uncovered meats experiment)
describe John Needham’s experiment to see if spontaneous generations could be true for microbes, include results
put mutton broth in flasks, boiled the flasks, then sealed them
results: broth became cloudy and contained microorganisms
describe Lazzaro Spallanzani’s experiement to see if spontaneous generation could be true for microbes, include results
put muttom broth in flasks, sealed them, and then boiled them
results: NO growth of microorganisms
describe Louis Pasteur’s experiments concerning spontaneous generation, include results
- placed nutrient solution in swan-neck flasks (long curved necks)
- boiled solutions
- broke neck of one flask, left other intact, exposed both to air
results: no growth of microorganisms in intact flask, grwoth in broken flask
what was the importance of Pasteur’s experiments?
disproved spontaneous generation
was the role of microorganisms in disease immedieately obvious (historically?)
no
what was infectious disease originally thought to be caused by?
supernatural forces or an imbalance of the four bodily-fluuid humors
what was needed to establish the connection between microorganisms and disease?
development of techniques for studying microbes
what did the earliest microbe studies focus on?
plants and fungi
what did Joseph Lister do?
provided indirect evidence that microorganisms were causal agents of disease
how did Joseph Lister provide indirect evidence that microorganisms were causal agents of disease?
developed a system of surgery designed to prevent microorganisms from entering wounds and methods for treating instruments and surgical dressings
what was the result of Joseph Lister’s new surgery system?
his patients had fewer post op infections
who provided the final, definitive proof of the role of microorganisms in disease?
Robert Koch
what did Robert Koch do?
established the relationship between Bacillus anthracis and anthrax
how did Robert Koch do his thing?
using criteria deeloped by his teacher
who was Robert Koch’s teacher?
Jacob Henle
what did Robert Koch’s criteria become known as, and what are they?
Koch’s postulates: still used today to establish the link between a particular microorganism and a particular disease
list Koch’s 4 postulates
- the microorganism must be present in every case of the disease but absent from healthy individuals
- the suspected microorganisms must be isolated and grown in a pure culture
- the same disease must result when the isolated microorganism is inoculated into a healthy host
- the same microorganism must be isolated again from diseases host
give Koch’s experimentation involving the first postulate
developed a staining technique to examine human tissue; identified Mycobacterium tuberculosis in diseased tissue
give Koch’s experimentation involving the second postulate
grew M. tuberculosis in pure culture on coagulated blood serum
give Koch’s experimentatio involving the third postulate
injected cells from the pure culture of M.tuberculosis into guinea pigs, who subsequently died of tuberculosis
give Koch’s experimentation involving the fourth postulate
isolated M. tuberculosis in pure culture from the dead guinea pigs
give 6 instances where Koch’s postulates would NOT be useful
- subclinical diseases: no symptoms to track when inoculating host
- when genetics skews the disease: some symptomatic, some not
- for some microbes that can’t be grown in culture: like leprosy
- when the animal model is not effective or is not the same as human
- in the case of opportunistic agents or immunocomrpomised individuals
- if an organism gains virulens: process is changed
list 4 things that Koch’s work led to the discovery or development of
- agar
- petri dishes
- nutrient broth and nutrient agar
- methods for isolating organisms
list 4 discoveries that came out of the golden age of microbiology ushered in
- restriction endonucleases
- first novel recombinant molecule
3, DNA sequencing methods - bioinformatics and genomic sequencing and analysis
what is medical microbiology?
study of diseases of humans and animals
what is public health microbiology?
study of control and spread of communicable diseases
what is immunology?
study of how the immune system protects a host from pathogens
what is microbial ecology?
concerned with the relationship of organisms with their environment
what percentage of the earth’s microbial population have been cultured?
less than 1%
what is agricultural microbiology?
concerned with the impact of microorganisms on agriculture
list two fields within agricultural microbiology
- food safety microbiology
2. animal and plant pathogens
when did industrial microbiology begin?
in the 1800’s
what does industrial microbiology include?
- fermentation
- antibiotic production
- production of cheese, bread, etc.
what is microbial physiology?
studies metabolic pathways of microorganisms
what is molecular biology, microbial genetics, and bioinformatics?
study the nature of genetic information and how it regulates the development and function of cells and organisms
what is a model system of genetics?
microbes
