Chapters 1 & 10 Flashcards

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1
Q

Microbiology

A

The study of “small organisms,” which are usually invisible to the naked eye; 20 nanometers: smallest virus - 3-4 um, largest - protozoans

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2
Q

Microbes

A

General term encompassing microorganisms and viruses; diverse in terms of their appearance, metabolism, physiology, reproduction, and genetics. Ex. bacteria, viruses, protist, fungi, helminthes (larva stages - parasitic worms)

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3
Q

Leeuwenhoek (1632-1723)

A
  • Inventor of the first microscope, which could magnify objects up to 300X
  • First to use microscopes to observe microorganisms in pond water (1674), which he called “animacules”
  • Created detailed descriptions of his findings (pond water, plants, insects, tooth scrapings, etc.) over the next 50 years
  • Considered to be the “father of microbiology”
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4
Q

Robert Hooke

A

Fist to describe “cellulae” (small rooms) in cork in 1665, which led to the formulation of the cell theory by others

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5
Q

Matthias Schleiden and Theodor Schwann

A

Independently published statements that “cells are the basic organizational unit of all living things” - The Cell Theory (1800s)

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6
Q

Spontaneous Generation

A

The discredited belief that organisms could arise from non-living matter (worms on meat/rats from hay)

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7
Q

Biogenesis

A

All living cells arise from other pre-existing living cells

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8
Q

Science

A

An organized body of knowledge about the natural world

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9
Q

Scientific Method

A

A series of steps used to gain information about the natural world:

  • Make an observation/identify a problem
  • Gather information about observation/problem
  • Formulate a hypothesis (educated guess)
  • Conduct a controlled experiment: contol group, experimental group, collect data
  • Conclusion: does your data support or refute the hypothesis
  • Peer review
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10
Q

The Progression of Scientific Ideas

A
  • Ideal hypothesis is generated
  • Experimentation: hypothesis confirmed or rejected
  • Peer review/Publication
  • If published, scientific community conducts further experimentation
  • If experimental data is consistent and reliable then, with time, the original hypothesis becomes a theory
  • Consistently supported theories, over long periods of time, can be elevated to scientific law or a constant fact of nature
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11
Q

Francisco Redi

A

In 1668, he covered rotting meat with fine gauze, showing that maggots developed only in meat that flies could reach to lay eggs; spontaneous generation would not be refuted for another 200 years because many insisted that only spontaneous generation of microorganisms was disproved

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12
Q

Needham’s Hypothesis, Experiment, and Conclusion

A
  • He boiled chicken broth, put it in a flask, and sealed it
  • If microbes grew, then it could only be because of spontaneous generation
  • Microbes grew, but we now know this was because the flask was not sterilized before adding the broth
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13
Q

Spallanzani’s Hypothesis, Experiment, and Conclusion

A
  • He put broth in a flask, boiled it, and sealed it creating a vacuum (no air)
  • No microbes in the cooled broth
  • Critics said he didn’t disprove spontaneous generation, only that it required air
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14
Q

Louis Pasteur’s Experiments

A
  • Argued against spontaneous generation; allowed the free passage of air, but prevented the entry of microbes
  • Boiled meat broth in a flask which sterilized it; swan neck flask created a seal with water and bacteria
  • No microbes developed until flask was tilted so some broth flowed into the curved neck
  • Gravity had caused microbes to settle at the low point of the neck, never reaching the base until washed in with the broth
  • Could not be replicated by other scientists who used vegetable broth which contains many endospores; original experiment used meat broth (luck) which contains few endospores
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15
Q

John Tyndall

A

Explained the conflicting results of Pasteur’s experiments, and proved him correct; He concluded that some microorganisms exist in two forms:

  • a cell form that is easily killed by boiling
  • a cell form that is heat resistant: endospores
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16
Q

3 Things Proved by Pasteur’s Experiments

A
  • No living things arise by spontaneous generation
  • Microbes are everywhere (even in air and dust)
  • The growth of microbes causes dead plant and animal tissue to decompose and food to spoil (led him to develop the technique of pasteurization which kept wine from spoiling)

*Also contributed to the development of vaccines

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17
Q

Germ Theory of Disease (late 1800s)

A

Microbes cause disease, and specific microbes cause specific diseases; previously thought to be caused by “bad air” or linked to superstitions or religion (punishment)

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18
Q

Ignaz Semmelweis (1850)

A
  • Noted that the rate of childbirth infections were greater at teaching clinics than when staffed by midwives
  • Doctors went from mother to mother - microbes from infected patients could spread to other patients
  • Midwives only worked with one patient
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19
Q

Joseph Lister

A
  • Believed pus around wounds was caused by microorganisms and that if they were killed the wounds might heal faster
  • Dressed wounds in phenol soaked cloths, reducing the rate of infection and speeding up the healing process
  • Proposed and practiced the idea of antiseptic surgery (sprayed phenol of the patients)
  • Phenol is not only toxic to most microorganisms, but humans as well (powerful carcinogenic); no longer used as an antiseptic
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20
Q

Robert Koch (late 1870s)

A
  • Studied anthrax: disease of cattle/sheep but also in humans
  • Observed that microbes were present in all blood samples of infected animals
  • Isolated and cultivated these microbes (Bacillus anthracis)
  • Injected healthy animal with cultured bacteria and it became infected; blood sample showed same microbes
  • Proved that particular microbes cause particular diseases
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21
Q

Koch’s 4 Postulates Concerning Disease and Microorganisms

A
  • The suspect agent must be present in every individual with the disease
  • The suspect agent must be isolated and grown in pure culture
  • The pure culture must cause the disease when injected into a healthy, experimental animal
  • The suspect agent must be re-isolated from the experimental animal and re-identified in pure culture (eliminates coincidence)
22
Q

Free-Living Organisms

A

An organism that is not directly dependent on another organism for survival

23
Q

Autotrophs

A

Organisms that:

  • Use inorganic molecules or photons (light particles) to create cellular energy (ATP)
  • Use CO2 as their principle source of carbon atoms to create new organic molecules necessary for maintaining their life
24
Q

Photoautotrophs

A

Use light energy to create ATP, and CO2 for their carbon source

25
Q

Chemoautotrophs

A

Use inorganic molecules (e.g. hydrogen sulfide gas) to create ATP and CO2 as their carbon source

26
Q

Heterotrohps

A

Organisms that:

  • Use organic molecules from other organisms to create cellular energy (ATP)
  • Use organic molecules in other organisms to create new organic molecules necessary for maintaining their life
27
Q

Decomposers

A

Organisms that use simple organic molecules from dead organisms:

  • Use organic molecules from dead molecules to create cellular energy (ATP)
  • Use organic molecules form other dead organisms to create new organic molecules necessary for maintaining their life
28
Q

Symbiosis

A

Occurs when two organisms live together

  • symbiont: smaller organism
  • host: larger organism
29
Q

Mutualistic Symbiosis

A

Both the symbiont and the host benefit from the relationship; acid producing bacteria in the vagina retards growth of yeast while human provides a location, warmth, nutrition, and growth

30
Q

Commensalistic Symbiosis

A

The symbiont receives a benefit from the relationship but does not harm the host

31
Q

Parasitic Symbiosis

A

The symbiont benefits by the relationship but the host is harmed by it

32
Q

Exotic Parasites

A

A pathogen not typically found in the human body, but can invade and cause harm; most flu and cold viruses are not usually found in the human body, they must be introduced by a host

33
Q

Opportunistic (Endemic) Parasites

A

Pathogens that are normal residents of the human body, but only inflict harm to the host when its immunity is weakened; streptococcus pneumonia

34
Q

Taxonomy

A

The classification and identification of organisms

35
Q

Classification

A

The orderly arrangement of organisms into groups that have similar characteristics; all schemes are constantly under review and are subject to change

36
Q

Kingdom

A

The broadest classification of organisms; species in the classification level can be very different

37
Q

Questions Determining an Organisms Kingdom Classification

A
  • How many cells does the organism have? Unicellular or Multicellular
  • Does the cell(s) have a nucleus? Prokaryotic or Eukaryotic
  • How does the organism get its energy and nutrients? Autotroph or Heterotroph
  • Cell wall composition? Cellulose, Peptidoglycan, or Chitin
38
Q

Kingdom Monera/Prokaryotes

A
  • Prokaryotic
  • Unicellular
  • Chemoautotrophic or photoautotrophic or heterotrophic (decomposers, parasites, commensalistic, mutualistic)
  • Cell wall made from peptidoglycan in true bacteria
  • Ex: bacteria, blue-green algae, archeabacteria*
39
Q

Kingdom Protist

A
  • Eukaryotic
  • Unicellular
  • Photoautotrophic and/or heterotrophic
  • No cell walls
  • Ex: Amoebas, Paramecium
40
Q

Kingdom Fungi

A
  • Eukaryotic
  • Most are multicellular, but some are unicellular (yeast)
  • heterotrophic by absorption (strictly decomposers), secrete powerful enzymes that break down matter
  • Cell walls made from chitin
  • Ex: yeast, mold, mushrooms
41
Q

Plant Kingdom

A
  • Eukaryotic
  • Multicellular
  • Photoautotrophic: use photosynthesis to produce energy
  • Cell walls made from cellulose
  • Ex: mosses, ferns, conifers, flowering plants
42
Q

Animal Kingdom

A
  • Eukaryotic
  • Multicellular
  • Heterotrophic by consumption and digestion
  • No cell walls
  • Ex: coral, sponges, insects, reptiles, birds, mammals
43
Q

Carolus Linnaeus

A

In 1753, recommended the use of binomial nomenclature for the scientific naming of organisms; would reduce confusion in the scientific community; name would consist of two Latin words (dead language): genus name (always capitalized) and species name (never capitalized) which are either italicized or underlined; usually descriptive, honorary, or both

44
Q

Strains (Varieties)

A

Isolated sub-populations of bacteria that are of the same species but have slightly different characteristics

45
Q

Phylogenetic Tree

A

A branching diagram showing the inferred evolutionary relationship among organisms based upon similarities and differences in their physical and/or genetic characteristics

46
Q

Differences Between Domain Bacteria and Domain Archaea

A
  • Bacteria and Archaea are as genetically different as Bacteria and Eukarya
  • In Bacteria, the cell wall is made of peptidoglycan; Archaea have cell walls that are not made of peptidoglycan, composition varies greatly
  • Archaea can thrive in extreme environments: high salinity (10x ocean water), high or low temperatures (105’ C, 0’ C)
  • Archaea species rarely, if ever, cause disease
47
Q

Infectious Agents

A

An agent capable of causing an infection:

  • Capable of self-replications (some form of reproduction)
  • Free-living include bacteria, algae, fungi, protozoa, helminthes (larval stages)
  • Non-living include viruses, viroids, and prions
48
Q

Virus

A
  • Acellular: not considered prokaryotic or eukaryotic
  • A piece of DNA or RNA surrounded by a protective protein layer (capsid); no nucleus of organelles or cell membrane or cytoplasm
  • 1/10 to 1/1000 the size of an ordinary bacterial cell
  • nonmotile
49
Q

Viroid

A
  • A small piece of RNA that is not surrounded by a protein layer
  • Plant pathogens; uncertain for animals
  • Potato spindle tuber disease
50
Q

Prion

A
  • A small self-replicating protein, no RNA or DNA
  • Affect the structure of the brain or other neural tissue and all are currently untreatable and universally fatal
  • Bovine spongiform encephalopathy (“mad cow disease”)/Creutzfeldt-Jakob Disease (CJD)
51
Q

Microbe Functions Necessary for Human Life

A
  • Nitrogen Fixation: Bacteria convert nitrogen gas (N2) into a solid form that is usable by plants, then other organisms
  • Oxygen gas (O2) production
  • Biodegradation: Microorganisms can break down glucose and other organic debris in the process of decomposition, instead of it accumulating within the environment
52
Q

Economic Applications of Microbiology

A
  • Alcohol production; wine, beer, spirits (yeast)
  • Food production: vinegar, yogurt, cheese, bread
  • Drug production; Insulin, Interferon, ethanol, antibiotics
  • Bioremediation: Help clean up the environment; bacteria can often break down toxic or unwanted waste products (oil spills)
  • Agricultural: research has led to healthier livestock and disease-free crops