microorganisms and microbiology Flashcards

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1
Q

microorganisms

A

organisms too small to be clearly seen by the unaided eye

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2
Q

prokaryotic cells

A

bacteria and archaea
their contents are not divided into compartments by membranes - open

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3
Q

eukaryotic cells

A

plants, animals, fungi
have a nucleus and other membrane-bound organelles that separate some cellular materials and processes from others

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4
Q

three domain system for microorganisms

A

bacteria
archaea
eukarya

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5
Q

bacteria

A
  • usually single-celled
  • most have cell wall with peptidoglycan
  • most lack a membrane-bound nucleus
  • live in extreme environments (including our bodies)
  • both disease causing and non-disease causing exist
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6
Q

archaea

A
  • distinguished from bacteria by unique rRNA sequences
  • have unique membrane lipids
  • many live in extreme environments
  • some have unusual metabolic characteristics
  • do not directly cause disease in humans
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7
Q

two classifications of eukarya

A

protists
fungi

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8
Q

protists

A
  • unicellular, but generally larger than bacteria and archaea
  • protozoa - animal like metabolism
  • algae - photosynthetic
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9
Q

fungi

A
  • unicellular or multicellular
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10
Q

viruses

A

acellular entities that must invade a host cell to multiply

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11
Q

viroids

A

infectious agents composed only of ribonucleic acid

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12
Q

satellites

A

composed of a nucleic acid enclosed in a protein shell
must coinfect a host cell with a virus, called a helper virus, to complete their life cycle

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13
Q

prions

A

infectious agents composed only of protein, responsible for causing neurological diseases such as scrapie and mad cow disease

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14
Q

ribozymes

A

catalytic RNA molecules
RNA molecules that form peptide bonds

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15
Q

RNA world

A

describes the precellular stage in the evolution of life
- must of had lipid membrane formed around RNA

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16
Q

evidence of RNA world hypothesis

A
  • most cellular RNA in modern cells exists in and is associated with the ribosome to construct proteins
  • rRNA catalyzes peptide bond formation in protein synthesis
  • similar structures indicate RNA may be precursor to double stranded DNA
  • the energy source of current cells is a ribonucleotide (ATP)
  • RNA can regulate gene expression
17
Q

last universal common ancestor

A
  • most recent organism from which all three types of life arose
  • archaea and eukarya evolved independently of bacteria
18
Q

taxonomy

A

science of classifying living things
- classification
- nomenclature
- identification

19
Q

strain

A

descendants of a single, pure microbial culture
- can be characterized biochemically, morphologically, or pathogenically

20
Q

microbiology

A

study of microorganisms and the tools used for the study

21
Q

pure culture

A

aka axenic culture
isolated strain - removed from their normal habitats and grown in isolation

22
Q

francesco stelluti

A

earliest microscopic observation
bees and weeviles btw 1625 and 1630

23
Q

robert hooke

A

published drawing of the fungus Mucor in 1665

24
Q

antony van leeuwenhoek

A

first person to observe microorganisms accurately
1632-1723

25
Q

spontaneous generation

A

belief that living organisms could develop for nonliving matter
- discredited by francesco redi 1626-1697 - showed maggots on decaying meat came from fly eggs

26
Q

john needham

A

based on observation that boiled hay gives rise to microorganisms
- thought life from nonliving material
1713-1781

27
Q

lazzaro spallanzani

A

proved that they hay itself didn’t make microorganisms if in sealed environment
1729-1799

28
Q

louis pasteur

A
  • swan-neck flask experiments
    discredited spontaneous generation
29
Q

john tyndall

A

demonstrated that dust carries microorganisms
no dust = nutrient broths remained sterile, even if directly exposed to air
also provided evidence for the existence of exceptionally heat-resistant forms of bacteria
- discredited spontaneous generation
1820-1893

30
Q

ferdinand cohn

A

showed heat-resistant bacteria could produce endospores
- discredited spontaneous generation
1828-1989

31
Q

4 bodily-fluid humors infectious diseases were believed to be due to

A

blood, phlegm, yellow bile (choler), and black bile (melancholy)

32
Q

scientist who found early evidence for the relationship between microorganisms and disease

A
  • agostine bassi (1773-1856)
    showed a disease of silkworms was caused by a fungus
  • M. J. berkeley (1803-1889)
    demonstrated the potato blight of ireland was casued by a protozoan
  • heinrich de bary (1831-1888)
    showed fungi caused crop disease
  • louis pasteur (1882-1895)
    demonstrated microorganisms carried out fermentation
  • joseph lister (1827-1912)
    provided indirect evidence that microorganisms were the causal agents of disease
    developed an antiseptic surgery system to prevent microorganisms from entering wounds
33
Q

robert koch

A

1843-1910
koch’s postulates - provides the causal relationship btw a microorganisms and a specific disease
- demonstrated that mycobacterium tuberculosis causes tuberculosis

34
Q

limitations of koch’s postulates

A
  • some organisms cannot be grown in pure culture bc they rely on host cells
  • lack animal model
  • using humans in completing the postulates is unethical
  • molecular and genetic evidence may replace and overcome these limits
35
Q

steps in koch’s postulates

A
  1. the microorganisms must be present in every case of the disease but absent from healthy organisms
  2. the suspected microorganism must be isolated and grown in a pure culture
  3. the same disease must result when the isolated microorganisms is inoculated into a healthy host
  4. the same microorganisms must be isolated again from the diseased host
36
Q

immunological studies

A
  • edward jenner (1749-1823)
    used vaccination procedure to protect against smallpox
  • emil von behring (1854-1917) and shibasaburo kitasato (1852-1931)
    developed antitoxins (antibodies) for diphtheria
  • elie metchnikoff (1845-1916)
    discovered first immune system cells - phagocytic cells in blood engulf bacteria