Ch. 1 - Evolution Of Microorganisms And Microbiology Flashcards
(90 cards)
1
Q
What are the beneficial roles of bacteria?
A
- they have a global impact and maintain human health
- they breakdown dead plant and animal material which cycles elements in the biosphere
- they are used extensively and industry to make bread, cheese, antibiotic’s, vitamins, enzymes, and other products
2
Q
What does the domain eukarya include?
A
Microorganisms classified as protists or fungi; animals and plants are also placed in this domain
3
Q
Microorganisms
A
Organisms and acellular biological entities too small to be seen clearly by the unaided eye
4
Q
Viruses
A
- Acellular entities that must invade a host cell to multiply
- composed only of proteins and a nucleic acid
- can be extremely small
- cause many animal and plant diseases and have caused epidemics that have shaped human history
5
Q
What are the simplest viruses composed of?
A
Proteins and a nucleic acid
6
Q
How do viruses multiply?
A
They must enter host cells
7
Q
What group of organisms has the greatest number of taxa?
A
Microbes
8
Q
What is the main difference between prokaryotic and eukaryotic cells?
A
Prokaryotic cells lack a nucleus and membrane-bound organelles
•they also have plasmids which contain their DNA as opposed to chromosomes
9
Q
What are enzymes?
A
Catalytic proteins that speed up the myriad of chemical reactions that occur in cells
10
Q
Bacteria
A
- usually single celled organisms
- most have cell walls that contain the structural molecule peptidoglycan
- most exhibit typical prokaryotic cell structure (i.e., they lack a membrane-bound nucleus), a few members of the unusual phylum Planctomycetes have their genetic material surrounded by a membrane
- lack a nucleus and membrane bound organelles
11
Q
What entities in the field of microbiology are considered cellular?
A
•Fungi -yeast -molds •protists -algae -Protozoa -slime molds •bacteria -escherichia coli •archaea -methanogens
12
Q
What entities in the field of microbiology are considered acellular?
A
•viruses -consists of: protein and nucleic acid •virolds - consists of: RNA •satellites -consists of: nucleic acid, often RNA •prions -consists of: protein
13
Q
How can some microorganisms be macroscopic?
A
Because they are multicellular
14
Q
What are the three characteristics of cellular microbes?
A
- usually smaller than 1 mm in diameter
- often unicellular
- If multicellular, lack differentiated tissues
15
Q
What is the role of membrane-bound organelles in eukaryotic cells?
A
Separate some cellular materials and processes from others
16
Q
What are the five kingdoms of life?
A
- monera
- protista
- fungi
- animalia
- plantae
17
Q
LUCA
A
Last Universal Common Ancestor
18
Q
3 domains of cellular organisms
A
- Bacteria
- Archaea
- Eukarya
19
Q
Bacteria roles
A
- making of bread and cheese
- cycle elements in biosphere
- break down dead plant material
- produce vitamins and minerals
20
Q
Archaea features
A
- distinctive rRNA sequence
- lack peptidoglycans in their cell walls
- unique membrane lipids
- some have unusual metabolic characteristics, such as methanogens, which generate methane (natural) gas
- found in extreme environments, including high temps (thermophiles) and high salt concentrations (extreme halophiles)
21
Q
Protists
A
Eukaryotic organisms
22
Q
What was present in the atmosphere of early Earth?
A
•water vapor •carbon dioxide •nitrogen •in the oceans: -hydrogen -methane -carboxylic acids
23
Q
What are the roles of proteins?
A
•structural
•catalytic
-enzymes
24
Q
Ribozymes
A
Catalytic RNA molecules; can do both cellular work and replicate itself
25
What is the importance of cyanobacteria?
* released oxygen into earths atmosphere
| * allowed for aerobic respiration
26
Endosymbiotic hypothesis
•The origin of three eukaryotic organelles:
-mitochondria
-chloroplasts
-hydrogenesomes
• an interaction between two organisms in which one organism lives inside the other
• has been modified to suggest that the host became dependent on the gas hydrogen produced by the symbiont
27
How does the Endosymbiotic hypotheses occur?
•overtime a bacterial endosymbiont of an ancestral cell in the eukaryotic linage lost ability to live independently becoming either:
- mitochondrion if aerobic respiration was used
- chloroplast if photosynthesis was used
28
Hydrogen hypothesis
* modified for mitochondrion
| * asserts that endosymbiont was anaerobic bacteria that produced H2 and CO2 as end products of metabolism
29
How do most eukaryotic species increase diversity?
By reproducing sexually
30
How do most bacterial and archaeal species increase their diversity?
Horizontal gene transfer
| * they do not reproduce sexually
31
How does horizontal gene transfer occur?
* Genetic information from a donor organism is transferred to a recipient, creating a new genotype
* Thus genetic information can be passed from one generation to the next as well as between individuals of the same generation and even between different microbial species
32
Strains
* consists of the descendants of a single, pure microbial culture
* strains within a species may be described in a number of different ways
33
How do microbiologists name microbes?
* by using the binomial system of the 18th century biologist Carl Linnaeus
* The first part of the name which is capitalized is the generic name (i.e., The name of the genus to which the microbe belongs)
* The second part of the name which is uncapitalized is the species epithet
34
Pure or axenic culture
A distinct feature of microbiology in which microbiologist remove microorganisms from their normal habitats and culture them isolated from other microbes
35
Who is Robert Hooke?
* He is credited with publishing the first drawings of micro organisms in the scientific literature
* "Micrographia" was his book; One of the designs discussed in this book was probably a prototype for the microscopes built and used by the amateur microscopist Anthony van Leeuwenhoek
36
Who was Anthony van Leeuwenhoek?
* spent his spare time constructing simple microscope's composed of double convex glass lenses held between two silver plates
* his microscopes could magnify about 50 to 300 times, and he may have illuminated his liquid specimens by placing them between two pieces of glass and shining light on them at a 45° angle to the specimen plane
37
Spontaneous generation
• The belief that living organisms could develop from nonliving matter
38
Who was Felix Pouchet?
* he claimed to have carried out experiments conclusively proving that microbial growth could occur without air contamination
* his claim provoked Louis Pastuer to settle the matter of spontaneous generation
39
When did support for the idea that microorganisms cause disease occur?
Began to accumulate in the early 19th century from diverse fields
40
Who was Louis Pasteur?
* he demonstrated that all fermentations were due to the activities of specific yeasts and bacteria, and he published several papers on fermentation between 1857 and 1860
* made contributions to the field of medical microbiology and also food and dairy microbiology
41
Who was Joseph Lister?
* he provided indirect evidence for the germ theory of disease on the prevention of wound infections
* he developed a system of anti-septic surgery designed to prevent microorganisms from entering wounds
* Instruments for heat sterilized, and phenol was used on surgical dressings and at times sprayed over the surgical area
* The approach was remarkably successful and transformed surgery
42
Protozoa
* Unicellular, animal like Protists that are usually motile
* function as the principal hunters and grazers of the microbial world
* obtain nutrients by ingesting organic matter and other microbes
* can be found in many different environments, and some are normal inhabitants of the intestinal tract of animals, where they aid in digestion of complex matter such as cellulose
* A few cause disease in humans and other animals
43
Biovars
Variant strains characterized by biochemical or physiological differences
44
Morphovars
Strains which differ morphologically
45
Serovars
Strains that have distinctive properties that can be detected by antibodies
46
Pathovars
Pathogenic strains distinguished by the plants in which they cause disease
47
Koch's postulates
* Robert Koch's criteria for proving the causal relationship between a microorganism and a specific disease
* conducted an experiment injecting anthrax into healthy mice
48
Who was the first to use pure culture methods?
•Robert Koch during his studies on bacterial disease
49
Fungi roles
* making bread rise
* producing antibiotics
* decomposing dead organisms
* Mycorrhizal fungi- improve growth of plants in poor soils
* cause disease in plants and animals
* not photosynthetic
50
Who was Sergei Winogradsky?
* Made many contributions to soil microbiology
* he discovered that soil bacteria could oxidize iron, sulfur, and ammonia to obtain energy and that many of these bacteria could incorporate carbon dioxide into organic matter much as photosynthetic organisms do
* He also isolated anaerobic nitrogen fixing soil bacteria and studied the decomposition of cellulose
51
Major fields in microbiology
* medical microbiology
* immunology
* microbial ecology
* agricultural microbiology
* food and dairy microbiology
* industrial microbiology
52
How did industrial microbiology develop?
* did not begin until the 1800s
* developed in large part from Pasteur's work on alcoholic fermentations
* his success led to the development of pasteurization to preserve wine during storage
* his studies continued for almost 20 years
* One of his most important discoveries was that some fermentative microorganisms were anaerobic and could live only in the absence of oxygen, whereas others were able to live either aerobically or anaerobically
53
What is the main focus of an industrial microbiologist?
• The use of microbes in production
54
Who was Martinus Beijerinck?
* One of the great general microbiologist who made fundamental contributions not only to virology but to microbial ecology as well
* he isolated aerobic nitrogen fixing bacteria (Azotobacter spp.), a root nodule bacterium also capable of fixing nitrogen (genus Rhizobium), and sulfate reducing bacteria
55
Genome
All the genetic information that organism contains
56
Bioinformatics
* The application of computers to genetic sequence analysis gave rise to this
* manage the ever increasing amount of genetic information available for analysis
* also determine the function of genes and generate hypotheses that can be tested either in silico (I.e., the computer) or in the lab
57
Medical microbiology
* deals with diseases of humans and animals
* identifies the agents causing infections diseases and help plan measures for their control and elimination
* Frequently involved and tracking down new unidentified pathogens such as those causing the human version of mad cow disease, hantavirus pulmonary syndrome, and west Nile encephalitis
* also studied the ways in which microorganisms cause disease
58
Public health microbiology
* concerned with the control and spread of such communicable diseases
* Monitor the amount of diseases and populations
59
Immunology
* One of the fastest-growing areas in science
* much of the growth began with the discovery of HIV which specifically target cells of the immune system
* also deals with the nature and treatment of allergies and autoimmune disease such as rheumatoid arthritis
60
Microbial ecology
* Developed when early microbiologist chose to investigate the ecological role of micro organisms rather than the role in disease
* Today, a variety of approaches, including non-culture based techniques, are used to describe the vast diversity of microbes in terms of their morphology, physiology, and relationships with organisms and the components of their habitats
* The importance of microbes in global and local cycling of carbon, nitrogen, and sulfur is well documented; however, many questions are still unanswered
* Of particular interest is the role of microbes in both the production and removal of greenhouse gases such as carbon dioxide and methane
61
Agricultural microbiology
* main focus is crop and animal production
* A field related to both medical microbiology and microbial ecology
* Concerned with the impact of micro organisms on agriculture
* Microbes such as nitrogen fixing bacteria play critical roles in the nitrogen cycle and effect soil fertility
* Agricultural microbiologists work on methods to increase soil fertility and crop yields, study rumen microorganisms in order to increase meat and milk production, and try to combat plant and animal diseases
62
Two groups of organisms with prokaryotic cell architecture
* Bacteria
| * Archaea
63
Major types of protists
* Algae
* Protozoa
* Slime molds
* water molds
64
Algae
* photosynthetic
* they, together with cyanobacteria, produce about 75% of the planets oxygen and are the foundation of aquatic food chains
65
Slime molds
* Protists that behave like protozoa in one stage of their life cycle but like fungi in another
* in protozoan phase, they hunt for and engulf food particles, consuming decaying vegetation and other microbes
66
Water molds
* Protists that grow on the surface of freshwater and moist soil
* they feed on decaying vegetation such as logs and mulch
* some produce devastating plant infections including the great potato famine of Ireland
67
Fungi
* A diverse group of micro organisms that range from unicellular forms (yeasts) to molds and mushrooms
* Molds and mushrooms are multicellular fungi that form thin, threadlike structures called hyphae
* They absorb nutrients from there environment, including the organic molecules they use as sources of carbon and energy
68
Viroids
* acellular infection agent composed of RNA
| * cause numerous plant diseases
69
Satellites
* acellular infectious agent composed of RNA and nucleic acid
* Cause plant diseases and some important animal diseases such as hepatitis
70
Prions
* acellular infectious agents composed only of protein
| * are responsible for causing a variety of spongiform encephalopathies such as scrapie and mad cow disease
71
Extant organisms
* organisms present today, that are being used to explore the origin of life
* some have structures of molecules that represent "relics" of ancient life forms
* can provide scientist with ideas about the type of evidence to seek when testing hypotheses
72
What was the first direct evidence of primitive cellular life?
* 1977 The discovery of microbial fossils in the Swartkoppie chert
* chert is a type of granular sedimentary rock rich in silica
* About 3.5 billion years old
73
RNA world
* term coined by Walter Gilbert in 1986
* Used to describe a pre-cellular stage in the evolution of life in which RNA was capable of storing, copying, and expressing genetic information, as well as catalyzing other chemical reactions
* The discovery of ribozymes were a key discovery for this
74
Why is it believed that DNA Became the storage facility for genetic information?
It is more chemically stable than RNA
75
Who was Frederick Sanger?
* he introduced a method that has since been modified and adapted for use an automated systems
* Today entire genomes of organisms can be sequence in a matter of days
76
Stromatolites
•Layered rocks, often domed, that are formed by the incorporation of mineral sediments into layers of microbial mats
77
Universal phylogenetic tree
* developed by Norman Pace
* Based on comparisons of small subunit rRNA molecules, the rRNA found in the small subunit of the ribosome
* according to the tree, Archaea and Eukarya shared common ancestry but diverged and became separate domains
* other versions suggest that Eukarya evolved out of Archaea
78
Origin of mitochondria and chloroplasts
* both contain DNA and ribosomes; both are similar to bacterial DNA and ribosomes
* both organelles belong to the bacterial lineage based on SSU-rRNA analysis
* Rickettsia prowazekii - an obligate intercellular parasite in the cause of epidemic typhus; further evidence for origin of mitochondria comes from this
* Prochloron - and ancestor of cyanobacterial genus which contains species that live within marine invertebrates; chloroplasts of plants and green algae are thought to have descended from this
79
Species
* A group of interbreeding or potentially interbreeding natural populations that is reproductively isolated from other groups
* bacteria and Archaea species cannot be defined by this criterion, since they do not reproduce sexually
80
Who were Lucretius and Fracastoro?
•They suggested that disease was caused by invisible living creatures
81
Who was John Needham?
* reported the results of his experiments on spontaneous generation
* he boiled mutton broth in flasks that he then tightly stoppered
* eventually many of the flasks became cloudy and contained microorganisms
* He thought organic matter contained a vital force that could confer the properties of life on nonliving matter
82
Who was Lazzaro Spallanzani?
* Improved on Needham's experimental design by first ceiling glass flasks that contained water and seeds
* if the sealed flask's were placed in boiling water for about 45 minutes, no growth took place as long as the flasks remain sealed
* he proposed that air carried germs to the culture medium but also commented that the external air might be required for growth and animals already in the medium
* The supporters of spontaneous generation maintained that heating the air in seals flasks destroyed its ability to support life
83
Who was Theodore Schwann?
* He allowed air to enter a flask containing a sterile nutrient solution after an air had passed through a red hot tube
* The flask remained sterile
84
Who was Schroder and Dusch?
* allowed air to enter a flask of heat sterilized medium after it had passed through sterile cotton wool
* no growth occurred in the medium even though the air had not been heated
85
Who was John Tyndall?
* in 1877 he demonstrated that dust did indeed carry germs and that of dust were absent, broth remained sterile even if directly exposed to air
* provided evidence for the existence of heat resistant bacteria
86
Who was Ferdinand Cohn?
* discovered that heat resistant bacteria recognized by Tyndall were species capable of producing bacterial endospores
* he played an instrumental role in establishing a classification system for bacteria based on their morphology and physiology
87
Role of four humors
* blood, phlegm, yellow bile, and black bile
| * The role of these in disease had been widely excepted since the time of the Greek physician Galen
88
Agostino Bassi
* demonstrated in 1835 that a silkworm disease was due to a fungal infection
* also suggested that many diseases were due to microbial infection
89
M. J. Berkeley
•Proved that the great potato blight of Ireland was caused by a water mold
90
Heinrich de Bary
• showed that smut and rust fungi caused cereal crop diseases
