Brock Biology of Microorganisms Chapter 1, Brock Biology of Microorganisms Chapter 1, Brock Biology of Microorganisms Chapter 5, Chapter 1 - Brock Biology of Microorganisms, Brock Biology of Microorganisms Chapter 2, Chapter 1 Microbiology Test bank
three domains (distinct lineages of microbial cells
-Bacteria (prok) -Archaea (prok) -Eukarya (euk)
endospore structure
-exosporium -spore coats -cortex -core -core wall (some)
The person who described the "wee animalcules" was
Antoni van Leeuwenhoek
Salvarsan
Arsenic compound to treat syphilis
Gluconacetobacter xylinus
Cotton production:
Developed by Carl Woese
Three domains based on cellular organization Bacteria Archaea Eukarya Protists Fungi Plants Animals
resolution
ability to distinguish two adjacent objects as distinct and separate
magnification
ability to make an object's image larger
-cidal agents
agents that kill microorganisms
Louise Pasteur developed the vaccine(s) for
anthrax, fowl cholera, and rabies
thermoplasmas
archaea that do not have cell walls
Microbes that live at high temperatures in hot springs are ________.
called extremophiles.
-taxis
directed movement in response to chemical or physical gradients
endosymbiotic hypothesis
idea that mitochondria nd chloroplasts descended from respiratory and phototrophic bacterial cells, respectively, association with non-phototrophic eukaryal hosts
metabolic model chemistry
idea that states that certain macromolecules and reactions are universal
30-300 colonies
ideal colony count for a good plate
growth
increase in the number of cells
Regarding early life on Earth
microbial life existed for billions of years before plant and animal life.
industrial microbiology
microbiology involved in the massive growth of naturally-occurring microbes to make low-cost products (ex antibiotics, enzymes, some chemicals)
Microbial ecology is the study of
microorganisms in their natural environments
The first documented description of a microorganism was of a ________ by ________.
mold / Robert Hooke
osmotaxis
response to ionic strength
bacillus
rod or cylindrical shape
Martinus Beijerinck
scientist who developed enrichment culture technique
Frederick Griffith
scientist who proved transformation with his mice and R/S strains; first to prove DNA was genetic material
Carl Woese
scientist who realized rRNA sequences could be used to infer evolutionary relationships
Emile Zuckerland and Linus Pauling
scientists that discovered molecular sequences and evolutionary relationships
James Watson, Francis Crick, Rosalind Franklin
scientists who first described the structure of DNA
Avery-MacLeoud-McCarty
scientists who proved transformation in vitro
autoclave
sealed device that uses steam under pressure; can kill endospores; high temp (not pressure) is what kills the microbes
metabolism
the chemical transformation of nutrients
cardinal remperatures
the minimum, optimum, and maximum temperatures at which an organism grows (typically less than 40 degrees C range)
microscopic cell count technique
which total cell count technique? -involves observing and counting cells present -works for dried on slides or liquid samples -counting chambers with squares etched in a slide for liquid samples DRAWBACKS: -cannot distinguish live vs. dead cells without stains -precision difficult -phase-contrast required if no stain -motile cells must be immobilied -debris often mistaken as cells USED IN: -natural samples -can provide phylogenetic info or metabolic properties -DAPI reacts with DNA
Rebecca Lancefield- Immunology
who discovered differences in the chemical composition of a polysaccharide in the cell walls of many pathogenic streptococci
D. smallpox
35) Which disease has been eliminated through the use of vaccines? A) tuberculosis B) measles C) rubella D) smallpox E) influenza
In what/which domain(s) of life is/are microorganisms represented?
Archaea, Bacteria, and Eukarya
Differential selection and reproduction of phenotypes occurs during a process called A) cellular differentiation. B) evolution. C) growth. D) transformation.
B
T/F Differentiation occurs only in multicellular organisms.
False
Escherichia coli
Pseudomonas putida a gene from the soil bacterium that converts the bacterial by product indole to indigo when this bacteria is added.
________ was the first to identify a new form of autotrophy in which energy is obtained from oxidizing inorganic compounds called ________.
Sergei Winogradsky / chemolithotrophy
biofilm stages of growth
Stage I: planktonic cells attach Stage II: sticky matrix forms
mitochondria
THE POWERHOUSE OF THE CELL -carry out respiration and oxidative phosphorylation for aerobic eukaryotes -1000+ per cell (few) -surrounded by two membranes
Pasteurization
The application of a high heat for a short time to kill harmful bacteria in beverages
T/F Both environmental conditions and nutrient resources strongly influence the composition of a microbial community.
True
~0.5 billion y.a.
When did plants and animals appear on Earth?
planktonic growth
growth as suspension
chemostat
most common type of continuous culture device
endoplasmic reticulum (ER)
network of membranes continuous with nuclear membrane
enzymes
protein catalysts
ribosomes
protein-synthesizing structures
phototaxis
response to light
Antoni van Leeuwenhoek
scientist to first describe bacteria using his lgiht microscope
A microbial cell's membrane is considered ________, because its internal constituents are maintained within the cell. However, it also imports and exports other molecules in response to its environment.
semipermeable
microbial ecology
the study of microbes in their natural environment
enrichment culture techniques
ways to isolate microbes using particular metabolic characteristics from nature
motility
when cells move by self-propulsion
D. using a sterile liquid and eliminating exposure to microorganisms
20) If you were setting up an experiment to disprove spontaneous generation in a liquid medium, which of the following would be essential to the experiment? A) supplying the liquid with nutrients B) starting with a liquid that contains microorganisms C) adding antibiotics to the liquid D) using a sterile liquid and eliminating exposure to microorganisms E) adding carbon dioxide to the liquid
A. Louis Pasteur
21) The arguments supporting spontaneous generation were finally disproved by A) Louis Pasteur. B) Francesco Redi. C) Rudolf Virchow. D) John Needham. E) Lazzaro Spallanzani
E all of the answer choices are correct
22) Regarding Louis Pasteurs experiments with the S-neck flask, which of the following statements is TRUE? A) Air exchange was involved. B) A food source was provided. C) The possibility of contamination was removed. D) All preexisting microorganisms were killed. E) All of the answer choices are correct.
Microbial sterilization is used to A) decrease the possibility of contaminants growing in a culture. B) kill bacteria but not necessarily viruses or other microbes. C) kill all microbes in or on objects. D) clean a work area.
C
Mycobacterium tuberculosis is very difficult to stain because of the A) presence of ribosomes in the cytoplasm. B) location of the DNA within the cell. C) large amounts of a waxy lipid present in its cell wall. D) lack of a cell wall.
C
Predict how Pasteur's conclusions on spontaneous generation with swan flasks would have changed if he worked with and maintained the flasks in a sterile laminar flow hood. A) Sterilization of the swan flask solutions would not have been necessary to reject spontaneous generation. If he did sterilize the flasks, the spontaneous generation hypothesis would have been supported. B) His incubation times would not have been sufficient to refute spontaneous generation. C) Pasteur's flasks never would have putrefied, and the experiment would not have refuted spontaneous generation. D) Viruses would have still been present, and his conclusion would have been unchanged.
C
The disease anthrax is caused by the pathogenic bacterium ________, which produces heat-resistant structures known as ________. A) Azotobacter chroococcum / endospores B) Azotobacter chroococcum / plasmids C) Bacillus anthracis / endospores D) Bacillus anthracis / plasmids
C
The first documented description of a microorganism was of a ________ by ________. A) bacterium / Ferdinand Cohn B) fungus / Robert Koch C) mold / Robert Hooke D) yeast / Martinus Beijerinck
C
Which of the following statements is FALSE? A) Microbial cells exist as single cells. B) Microbial cells carry out their life processes of growth independently. C) Microbial cells include both bacteria and viruses. D) Microbial cells exclude the cells of plants and animals.
C
Which scientific objective is LEAST related to microbial genetics? A) determining the ancestral origin of a recently discovered bacterium B) identifying mutations in a bacterial population C) identifying quorum sensing interactions among bacteria D) manipulating a microorganism for bioremediation
C
Describe two capabilities of microbes that exemplify their dynamic nature in interacting with their environment.
Answers could possibly include cell-cell communication, ability to move (motility), ability to differentiate, and exchange of materials (any two).
List three contributions of Ferdinand Cohn to the development of microbiology.
Answers could possibly include: founding bacteriology as a separate science, studying Beggiatoa, discovering the genus Bacillus (along with its endospore formation and its life cycle), and devising methods to prevent contamination.
Explain why infectious diseases are much less lethal in developed countries than in underdeveloped countries.
Answers will vary but should emphasize ways in which increased knowledge about microbial pathogenesis has influenced preventative care (e.g., sanitation) and treatment (e.g., antimicrobial drugs).
Compare and contrast the functions microbes serve in the digestive systems of both humans and rumens (e.g., cattle).
Answers will vary but should focus on humans having a high cell localized density in the colon (large intestine), whereas rumens have higher microbial populations in the rumen. Microbes in both systems aid in digestion and improve nutrition/health of the host.
Explain why microbial cells are excellent models for understanding cell function in higher organisms.
Answers will vary but should include commonality of function, biochemical and genetic similarities, and ease and speed with which they can be grown in large quantities.
Explain how you would use Robert Koch's postulates to determine that Streptococcus pyogenes is the causative agent of streptococcal pharyngitis ("strep throat").
Answers will vary but will need to detail how S. pyogenes will be subjected to all four postulates.
Compare and contrast the leading causes of death in 1900 with the leading causes of death today. What roles have microbiologists played in the dramatic changes that are evident?
Answers will vary, but a focus should be that pathogens that killed people in the early 1900s are now treatable due to knowledge learned from microbiologists.
Microbes were first formally observed during the mid-1600s, but the cell theory was not enunciated until 1839. Write a brief essay explaining why microbiology did not become a formally recognized science until Louis Pasteur's and Robert Koch's time.
Answers will vary, but a theme should be the lack of powerful microscopy tools. Without sufficient microscopes individual cells could not be seen, but the activities of microorganisms could be observed, such as the production of ethanol in Louis Pasteur's experiments on fermentation.
Explain the nature and function of an enrichment culture.
Answers will vary, but an enrichment culture uses media, chemicals, or culture conditions to select for or encourage the growth of organisms with specific characteristics. An answer could describe providing only carbon dioxide as a source of carbon to select for autotrophs, for example.
The text states that antibiotics are derived from microorganisms. What is the benefit to an antibiotic-producing microorganism of producing an antibiotic in its natural habitat?
Answers will vary, but it must first be stated the antibiotic-producing microbe would need to be resistant to the antibiotic. This should then follow into a discussion on how antibiotic production could be viewed as a way to persist in the environment, such as maintaining dominance in a community over others.
Provide evidence supporting the statement that an "ecosystem is controlled by microbial activities."
Answers will vary, but one example could be oxygen depletion, where a loss of oxygen would then favor anaerobic microorganisms.
Using specific examples, explain why it is sometimes impossible to satisfy Robert Koch's postulates.
Answers will vary, but one issue is the consideration for a model animal host that will react to the (human) pathogen in the same manner as in a human host. For example, a chicken would not show flu-like symptoms when infected with the influenza virus. Another issue is the inability to cultivate some microorganisms outside of the host.
________ was the first to describe microorganisms, while ________ was the first person to see bacteria.
Robert Hooke / Antoni van Leeuwenhoek
Developments in the fields of immunology and medical microbiology were practical extensions of the work of
Robert Koch
Walther Hesse and _____________ pioneered the use of agar as a solidifying agent
Robert Koch
Microbial biochemistry most specifically involves the discovery of microbial ________ and the ________ they perform.
biomolecules / functions
The process whereby microorganisms are used to help clean up pollution created by human activities is known as
bioremediation
The production of human proteins (e.g., insulin) by genetically engineered microorganisms is an example of ________, a subdiscipline of microbiology.
biotechnology
cytoplasmic membrane
Surrounds the cytoplasm, separates it from the environment and is selective with in take and out take of wast
Microbial biochemistry involves the discovery of microbial ________ and the ________ they perform. A) biomolecules / functions B) enzymes / catalyses C) metabolic pathways / reactions D) biomolecules, enzymes, and metabolic pathways / functions
D
Microbial ecology is the study of A) microbial processes in the rhizosphere that benefit plant growth. B) the diversity and activities of microorganisms. C) the grouping and classifying of microorganisms. D) microorganisms in their natural environments.
D
Microorganisms play key roles in the cycling of important nutrients in plant nutrition, particularly those of A) carbon. B) nitrogen. C) sulfur. D) carbon, nitrogen, and sulfur.
D
Most prokaryotic cells reside A) on Earth's surface. B) in lakes, rivers, and oceans. C) in and on nonprokaryotic organisms (including humans and other animals). D) in the oceanic and terrestrial subsurfaces.
D
Protein catalysts involved in the acceleration of the rate of chemical reactions are called A) catalytic converters. B) growth agents. C) evolutionary molecules. D) enzymes.
D
T/F Treponema pallidum, a bacterium associated with syphilis, is not considered a pathogen because to date it remains unculturable in the lab, and, therefore, Koch's postulates are unable to be fulfilled.
False
T/F Metabolism is a unifying characteristic of all cellular organisms.
True
T/F Not only do some microorganisms tolerate extremely hot temperatures, some actually require high temperatures for optimal growth.
True
T/F Sergei Winogradsky worked with bacteria involved in cycling nitrogen and sulfur.
True
T/F The discipline of microbiology is intimately associated with biochemistry and genetics, because cells are both biochemical catalysts and genetic coding devices.
True
T/F The environment in which a microbial population lives is called its habitat.
True
T/F The environment in which a microbial population lives is its habitat.
True
T/F Today, the enrichment culture technique developed over a century ago by Martinus Beijerinck remains a feasible approach to discovering bacteria capable of degrading pollutants.
True
Bacteria
Prokaryotes "Prenucleus" Single-celled Peptidoglycan cell walls Divide via binary fission Derive nutrition from organic or inorganic chemicals or photosynthesis
peritrichous flagella
Multiple flagella may be randomly distributed over the entire bacterial cell
Archaea (ar-KE-ah)
Prokaryotes Lack peptidoglycan cell walls Often live in extreme environments Include: Methanogens Extreme halophiles Extreme thermophiles
Microorganisms play key roles in the cycling of important nutrients in plant nutrition, particularly those of
carbon, nitrogen, and sulfur
phospholipid molecule
composed of a glycerol backbone, two fatty acid chains, and a phosphate group, a polar head. - chain is made with a lot of Hydrogen bonding to Carbon no sub chains _ polar hydrophilic head that exposed to environment -fatty acid tail that points in wards that hydrophobic area
spirillum
curved or spiral shape
Approximately two billion years ago, ________ were primarily responsible for initially oxygenating Earth.
cyanobacteria
Cyanobacteria and purple sulfur bacteria both obtain energy from light. However, only the ________ are capable of releasing ________.
cyanobacteria / oxygen
phylogenetic tree
depicts phylogeny of all cells
Robert Koch contributed to the field of microbiology by being the first person to
develop the tuberculin test, formulate four postulates for definitively linking a specific microorganism to a specific disease, and use agar as a solidifying agent in growth media
Which of the following is NOT an accomplishment of Louis Pasteur?
developed enrichment culture techniques
Some microorganisms can undergo ________ in which various cell types can become specialized and arise from one parent cell type.
differentiation
transmission electron microscopes (TEM)
e-microscope type: -specimens are stained with high atomic weight substances that scatter e- well and improve contrast -negative staining allows direct observation of intact cells/components
scanning electron microscopes (SEM)
e-microscope type: -specimens coated with heavy metals (ex. gold) -scattered e- collected to produce image -only surface can be visualized
Biological catalysts involved in the acceleration of the rate of chemical reactions are called
enzymes
Differential selection and reproduction of phenotypes occurs during a process called
evolution
Which of the following is/are characteristic of all cellular organisms?
evolution
instantaneous growth rate constant (k)
expresses rate of growth at any given instant (initial increases is slow but gains speed)
plasmids
extrachromosomal DNA that confers special properties (like antibiotic resistance) (found in prokaryotes)
thylakoids
flattened membrane discs that contain chlorophyll and ATP synthetic components; form proton motive force
cristae
folded internal membrane of the mitochondria
Bacillus anthracis deficient in its ability to differentiate would not be able to
form endospores
Martinus Beijerinck was the first to isolate
green algae, certain nitrogen-fixing root nodule bacteria, and certain sulfate-reducing bacteria.
exponential growth
growth of a microbial population in which cell numbers double within a specific time inteval
biofilms
growths on submerged surfaces (ex. pipes storage tanks, implanted medical devices)
Robert Koch received the 1905 Nobel Prize in Physiology or Medicine for
identifying Mycobacterium tuberculosis as the causative agent of tuberculosis
electron micrograph
image of an e-microscope
stroma
in chloroplasts, this contains large amounts of Rubusico (key for Calvin Cycle)
What field focuses specifically on the use of microbes to make products, such as antibiotics, on a large scale?
industrial ecology
The discovery of antibiotics and other important chemicals led to the field of
industrial microbiology
dilution rate
measured in F/V (F: flow is rate of adding fresh medium and removing spent medium/V: culture volume)
differential media
media that contains an indicator, usually a dye, that detects particular metabolic reactions during growth
selective media
media that contains compounds that selectively inhibit growth of some microbes but not others
cisternae
membrane-bound sacs in golgi complex
organelles
membrane-enclosed structures within a cell
radiation
method of sterilization used in the medical field and food industry (approved by WHO)
glove box
method that can flush or consume oxygen (reducing technique)
microbes as disease agents
microbes that present as bacterial and viral pathogens
electron microscopes
microscopes that use electrons instead of visible light to image cells and structures
phase-contrast microscopy
microscopy that improves image contrast of unstained, live cells utilizing a phase ring; appears as dark cells on a light background
confocal scanning laser microscopy (CSLM)
microscopy that uses a computerized microscope and a laser source to generate 3D image; computer takes pics of layers and compiles them into 3D images
differential interference contrast (DIC) microscopy
microscopy that uses a polarizer to create two distinct beams of polarized light; affords a 3D appearance
compound light microscopy
microscopy that uses visible light to illuminate cells
fluorescence microscopy
microscopy used to see specimens that emit light after illumination with different wavelengths; appear to glow on black background due to filters; used in microbial ecology
dark-field microscopy
microscopy where light reaches the specimen from the sides after being scattered by specimen; image appears light on dark background; good for seeing motility
bright-field scope microscopy
microscopy where specimens are visualized because of differences in contrast between specimen and surroundings; pigmented microbes add contrast
Archaea and Bacteria are unified as prokaryotes in lacking ________ which Eukarya contain, such as mitochondria.
nuclei and membrane-enclosed organelles
total maginfication
objective magnification x ocular magnification
polar flagella
one or more of this arising from one or both poles of a cell
cell wall
organelle only present in some microbes; provides extra protection and strength
dyes
organic compounds that bind to specific cellular materials
thermophiles
organisms classified by high growth optima; found in hot environments (45-80 dC)
psychrophiles
organisms classified by low growth optima; found in cold environments
mesophiles
organisms classified by midrange growth optima; most commonly studied organisms
hyperthermophiles
organisms classified by very high growth optima; found in extremely hot environments (ex. hot springs, deep-sea hydrothermal vents) (greater than 80 dC ranges; only prokaryotes)
extreme halophiles
organisms that REQUIRE very high levels of NaCl (15-30%); mostly Archaea
obligate anaerobes
organisms that are inhibited or killed by oxygen presence (ex. some Bacteria, Archaea, fungi, and protozoa)
facultative organisms
organisms that can live with or without oxygen
halotolerant
organisms that can tolerate some additional dissolved solutes but generally grow best in their absence
microaerophiles
organisms that can use oxygen only when it is present at reduced levels compared to air; due to limited respiration or oxygen sensitivity
anaerobes
organisms that cannot respire oxygen
halophiles
organisms that grow best at Aw=0.98 (seawater); have specific requirements for NaCl
alkaliphiles
organisms that grow best at high pH (8 or greater) -found in soda lakes and high-carbonate soils -used commercially in detergents -some have Na+ motive force as opposed to H+
acidophiles
organisms that grow best at low pH (<5.5) -cyto membrane stability so important here -some are obligate to this range
neutrophiles
organisms that grow optimally at pH 5.5-7.9
extremophiles
organisms that grow under very hot or very cold conditions
osmophiles
organisms that live in environments high in sugar as solute
extremophiles
organisms that live in habitats too harsh for other life forms (ex. hot springs, glaciers, high salt, acidity, alkalinity, pressure)
Xerophiles
organisms that live in very dry environments
Chemolithotrophy involves
oxidation of inorganic compounds
synthesis of flagella
steps to synthesize ??: (several genes required; filament grows from tip) 1) MS ring made first 2)other proteins and hook are made next
hopanoids
sterol-like molecules that help strengthen some bacterial cell walls
osmosis
water diffused from high to low concentrations
steady state:
what it's called when cell density and substrate concentration do not change over time
transcription
when DNA information is converted into RNA
translation
when RNA is used by ribosome to make protein
positive water balance
when cytoplasm has a higher solute concentration than the surrounding environment; water will move INTO cell
negative water balance
when cytoplasm has lower solute concentration than surrounding environment; water will flow OUT of cell unless cell has preventative mechanisms in place
differentiation
when microbes modify internal structures to form specialized cells
intercellular communication
when microbes respond to other microbes
spread plate method
plating method where sample is put on surface (topside) of medium
basic dyes
positively charged dyes that bind strongly to negatively-charged cell components (ex. nucleic acids, acidic polysaccharides, etc.) Examples are methylene blue, crystal violet, and safranin
cold shock proteins (chaperones)
proteins that help resist cold environments
min: 0 dC growth optima: less than or equal to 15 dC max: less than or equal to 20 dC
psychrophile cardinal temps
can grow at 0 dC but have optima of 20-40 dC
psychrotolerant cardinal ranges
Sergei Winogradsky
scientist -demonstrated that specific bacteria are linked to specific biogeochemical transformations -proposed concept of chemolithography -showed chemolithographs use carbon from CO2 (autotrophy) -first to show nitrogen fixations and nitrification
Robert Hooke
scientist to first describe microbes
A microbial cell's membrane is considered ________, because its internal constituents are maintained within the cell. However, it also imports and exports other molecules in response to its environment. A) differential B) microselective C) rigid D) semipermeable
D
Applied microbiology deals with important practical problems in A) medicine. B) agriculture. C) industry. D) medicine, agriculture, and industry.
D
Archaea and Bacteria are unified as prokaryotes in lacking ________ which Eukarya contain, such as golgi. A) membranes B) nuclei C) membrane-enclosed organelles D) nuclei and membrane-enclosed organelles
D
Basic microbiology can be used to A) probe the fundamental processes of life. B) study characteristics of cells of multicellular organisms. C) model our understanding of cellular processes in multicellular organisms, including humans. D) probe the fundamental processes of life, study characteristics of cells of multicellular organisms, and model our understanding of cellular processes in multicellular organisms, including humans.
D
Deduce why viruses are excluded from the ribosomal RNA-based tree of life. A) Some viruses contain multiple strands of RNA. B) Their genetic elements cannot be sequenced. C) They can infect other organisms, which complicates the genetic comparisons. D) They lack ribosomal RNA.
D
Determine which outcome is LEAST likely for a microorganism being motile. A) avoidance of predation by bacteriovores B) maintaining osmotic balance within a salt gradient C) movement towards growth substrates D) transfer of plasmids to progeny
D
Developments in the fields of immunology and medical microbiology were practical extensions of the work of A) Sergei Winogradsky. B) Antoni van Leeuwenhoek. C) Joseph Lister. D) Robert Koch.
D
Deduce why viruses are excluded from the ribosomal RNA- based tree of life
they lack ribosomal RNA (rRNA)
gut microbiome
this digests complex carbohydrates in humans and synthesizes vitamins and other nutrients (microbes involved in this)
measuring chemotaxis
this involves inserting a capillary tube containing an attractant or a repellant in a medium of motile bacteria and seeing where microbes gravitate
enriched media
this media contains complex media plus highly nutritious materials (ex. serum or blood)
spirochetes
tightly coiled shape, appendaged bacteria, and filamentous bacteria (includes budding bacteria)
generation time
time required for microbial cells to double in number (can be affected by nutrition, genetics, and temperature)
decimal reduction time (D)
time required to reduce viability of microbe by tenfold
thermal death time
time to kill all cells at a given temperature; affected by population size
T/F Metabolism is a unifying characteristic of all cellular organisms.
true
The structure that confers structural strength on the cell is known as the A) cytoplasmic membrane. B) cell wall. C) ribosome. D) cytoplasm.
B
ionizing radiation
-EM radiation that produces ions and other reactive molecules upon collision -used to sterilize surgical supplies, plastic labware, drugs, fresh produce, meat
Approximately two billion years ago, ________ were primarily responsible for initially oxygenating Earth. A) algae B) Archaea C) cyanobacteria D) purple sulfur bacteria
C
In what/which domain(s) of life is/are microorganisms represented? A) Archaea B) Bacteria C) Eukarya D) Archaea, Bacteria, and Eukarya
D
Louis Pasteur developed the vaccine(s) for A) anthrax. B) fowl cholera. C) rabies. D) anthrax, fowl cholera, and rabies.
D
T/F According to our present understanding, each of the three major domains has what is known as its own universal ancestor.
False
T/F All microorganisms require molecular oxygen to carry on life functions.
False
T/F Electron microscopes have less resolving power (resolution) than light microscopes.
False
T/F Most microorganisms are pathogenic.
False
T/F The bubonic plague was caused by Yersinia pestis, a highly pathogenic virus.
False
lophotrichous flagella
Several flagella (tuft) can extend from one end or both ends of the cell
Spontaneous generation
The hypothesis that life arises from nonliving matter; a "vital force" is necessary for life
water activity (a sub w)
-pure water availability -ratio of vapor pressure of air in equilibrium with a substance or solution to the vapor pressure of pure water -range is 0-1 (no free water to pure water)
ultraviolet (UV) radiation (220-300 nm)
-radiation with sufficient energy to cause modifications and breaks in DNA -can help decontaminate surfaces, but can't penetrate solid, opaque, or light-absorbing surfaces
chemotaxis
-response to chemicals -exhibit "run and tumble" behavior
compatible solutes
-solutes used by a cell to maintain positive water balance (pumping solutes from environment into cell, synthesizing cytoplasmic solutes) -highly water soluble
Microbial sterilization is used to
kill all microbes in or on objects
Answer: TRUE
2) A student has obtained a sample of pond water for study. Using the high-power lens, he observes several cells with nuclei. He can conclude that the cells are NOT bacteria.
D. Mushroom
2) Each of the following organisms would be considered a microbe EXCEPT A) yeast. B) protozoan. C) bacterium. D) mushroom. E) virus.
disinfectants vs. sanitizers vs. antiseptics
(choose sanitizer, disinfectant, or antiseptic) 1) destroys all microorganisms, including endospores 2) reduce microbial numbers but do not sterilize 3) kill or inhibit microbial growth but are nontoxic enough to be applied to living tissues
toxic byproducts of oxygen
- superoxide anion (O2-) - hydrogen peroxide (H2O2) -hydroxyl radical (•OH) (enzymes can neutralize most of these for us)
B. Jenner
30) Which physician is first associated with vaccination? A) Ehrlich B) Jenner C) Lister D) Koch E) Escherich
What doesn't peripheral membrane cross the cell membrane ?
-They are hydrophilic - The cells is negatively charged in side the cell so they are probably negatively charged
hamus/hami
-archaeal "grappling hooks" help surface attachment, forming biofilms -resemble pili except for barbed terminus
capsules and slime layers
-assist in surface attachment -develop and maintain biofilms -protect against phagocytosis -prevent dehydration/dessication
biofilms
-attach polysaccharide matrix containing embedded bacteria -form in stages -prevent harmful chemicals (like antibiotics) from penetrating -prevent protists from grazing -prevent washing away of cells -can affect human health, water distribution cycles, and fuel storage
Why use continuous culture?
-can maintain exponential growth phase for weeks/months -used to study physiology, microbial ecology and evolution, enrichment and isolation of bacteria from nature
sources of radiation
-cathode ray tubes -X-rays -radioactive nucleotides
chloroplasts
-chlorophyll-containing organelle found in phototrophic eukaryotes -have double membrane
gas vesicles
-confer buoyancy in planktonic cells -conical-shaped, gas-filled structures made of protein -impermeable to water and solutes composed of GvpA and GvpC -function by decreasing cell density
endospore features
-contains dipicolinic acid -enriched in Ca2+ -core has acid-soluble spore proteins that bind and protect DNA and function as carbon and energy source for outgrowth
nucleus
-contains the chromosomes -DNA wound around histones -enclosed by two membranes that interact with nucleoplasm and cytoplasm
culture growth rate and population density can be controlled by these two factors:
-dilution rate -concentration of a limiting nutrient
superoxide dismutase
-enzyme that neutralizes toxic byproducts of oxygen -converts superoxide anion to hydrogen peroxide, which then converted to water
superoxide reductase
-enzyme that neutralizes toxic byproducts of oxygen -in some strict anaerobes, converts superoxide anion to hydrogen peroxide WITHOUT producing molecular oxygen
catalase and peroxidase
-enzymes that neutralize toxic byproducts of oxygen -convert hydrogen peroxide to molecular oxygen and water
fimbriae and pili
-filamentous protein structures -help organisms stick to surfaces or form pellicles
hydrogenosomes
-found in anaerobic, strict fermenters -similar size to mitochondria -lack TCA cycle enzymes and cristae 0major function is oxidation of pyyruvate to H2 and CO2, producing CH4--> acetate is secreted
sessile growth
-growth when attached to surface -can develop into biofilms
archaella specifics
-half diameter of bacterial flagella -move by rotation -have different filament proteins with little homology to bacterial flagelin -similar to type IV pili
rough ER
-has ribosomes -major producer of glycoproteins and new membrane material
archaeal membranes
-have ether linkages in phospholipids of archaea (in contrast to ester links) -lipids have isoprenes, not fatty acids -some only have monolayer if lipids (not bilayer, especially in thermophilic)
endospores
-highly differentiated cells resistant to heat, harsh chemicals, and radiation -present only in GRAM POSITIVE bacteria -nearly 20 types
nucleolus
-inside nucleus -site of ribosomal RNA synthesis
smooth ER
-lacks ribosomes -participates in the synthesis of lipids and carbohydrate metabolism
advantages to being small
-larger surface area to cell volume ratio -grow faster -evolve faster ( due to mutations)
optical density (OD)
-measurement from a spectrophotometer at a specified wavelength -proportional to cell number within limits -standard curve established to relate to direct cell count
activities of microbial cells
-metabolism -motility -differentiation -intercellular communication -evolution -live in microbial communities
filtration
-method of sterilization that avoids the use of heat on sensitive liquids and gases -used for HEPA filters -membrane filters function like a sieve -nucleopore filters used in scanning microscopy
heat sterilization
-most widely used technique for controlling microbial growth
culture media
-nutrient solutions used to grow microbes in the laboratory -typically sterilized in an autoclave
viruses
-obligate parasites that only replicate within a host cell -do not carry out own metabolism -small genomes of double or single strand DNA or RNA -very diverse
aerobes
-organisms that require oxygen (respiration) and grow at full oxygen tensions (~21%) -require extensive aeration (shaking, bubbling) to grow in lab
Bacteria cytoplasmic membrane
-phospholipid bi layer with embedded proteins -Hydrophobic and philic - Inside cell negative and out side +
pour plate method
-plating method where sample is mixed with medium before fully solidifying -can be used to find anaerobic bacteria
archaeal cell walls
-these walls do not have peptidoglycan -many, but not all, have pseudomurein
bacterial cell walls
-these walls have peptidoglycan -phospholipid bilayer having hydrophobic and hydropilic heads -
gliding motility
-this movement only executed by bacteria; not archaea -slower and smoother than swimming -movement typically occurs away from colong -requires surface contact
disc infusion assay
-uses solid media -where an antimicrobial agen is added to filter paper disc and then it diffuses into agar
endospore life cycle
-vegetative cell converted to non-growing, heat-resistant, light-refractive structure due to lack of essential nutrients (C and N, etc) -will beging growing again when conditions are met (triggered by signals due to genetics) -Steps are ACTIVATION, GERMINATION, OUTGROWTH
Structure phospolipid molecule
-water attracting head (polar) - fatty acid tall that has a lot of hydrocarbons -ester linkage (bilayer and Pro or Euk)
Phases of Microbial Growth Cycle
1) Lag phase 2) Exponential phase 3) Stationary phase 4) Death phase
E. Smog Production
1) Microorganisms are involved in each of the following processes EXCEPT A) infection. B) decomposition of organic material. C) O2 production. D) food production. E) smog production.
D. blood
42) Normal microbiota are typically found in and on all the following body locations EXCEPT the A) skin. B) mouth. C) colon. D) blood. E) upper respiratory system.
E. cilia, flagella and psuedopods
11) Protozoan motility structures include A) cilia. B) flagella. C) pseudopods. D) cilia and pseudopods only. E) cilia, flagella, and pseudopods.
A. cannot reproduce by themselves
12) Viruses are not considered living organisms because they A) cannot reproduce by themselves. B) are structurally very simple. C) can only be visualized using an electron microscope. D) are typically associated with disease. E) are ubiquitous in nature.
A. virus
13) The infectious agent that causes AIDS is a A) virus. B) bacterium. C) yeast. D) protozoan. E) mold.
A. animalia
14) Which of the following is NOT a domain in the three-domain system? A) animalia B) archaea C) bacteria D) eukarya
C. cellular organization
15) Classification of organisms into three domains is based on A) the presence of a cell wall. B) the number of cells in the organism. C) cellular organization. D) nutritional requirements. E) cellular proteins.
A. have diverse cell wall compositions
16) Archaea differ from bacteria in that archaea A) have diverse cell wall compositions. B) lack nuclei. C) use organic compounds for food. D) reproduce by binary fission. E) are prokaryotic
A. Robert Hooke
17) Who is credited with first observing cells? A) Robert Hooke B) Anton van Leeuwenhoek C) Robert Koch D) Louis Pasteur E) Carolus Linnaeus Answer: A
B. Anton van Leeuwenhoek
18) Who is credited with first observing microorganisms? A) Robert Hooke B) Anton van Leeuwenhoek C) Robert Koch D) Louis Pasteur E) Carolus Linnaeus
B. development of life forms from preexisting life forms
19) Biogenesis refers to the A) spontaneous generation of organisms from nonliving matter. B) development of life forms from preexisting life forms. C) development of aseptic technique. D) germ theory of disease.
A. fermentation
23) The microbial process of converting sugars to alcohol is known as A) fermentation. B) pasteurization. C) tyndallization. D) lyophilization. E) alcoholism.
C. Koch
24) Proof that a microbe could cause disease was provided by A) Pasteur. B) Lister. C) Koch. D) Wasserman. E) Semmelweis.
A. Lister
25) The use of phenol (carbolic acid) as a wound disinfectant was first practiced by A) Lister. B) Semmelweis. C) Pasteur. D) Holmes. E) Koch.
E. molds, yeast and mushrooms
26) Mycology is the study of A) mycoplasma. B) mushrooms. C) protozoa. D) molds. E) molds, yeast, and mushrooms.
C. obtain a sample of blood or other body fluid from a disease animal
27) The first step for directly linking a microbe to a specific disease according to Kochs postulates is to A) culture the blood or other body fluid from a diseased animal using nutrient medium. B) inject a sample of blood or other body fluid from a diseased animal into a healthy animal. C) obtain a sample of blood or other body fluid from a diseased animal. D) compare the blood of a sick animal to blood obtained from a healthy animal. E) isolate microbes from the blood of healthy animals.
A. determination of the cause of a new emerging disease by scientists studying disease transmission
28) In which of the following situations would Kochs postulates be utilized? A) determination of the cause of a new emerging disease by scientists studying disease transmission B) development of a new antibiotic in a pharmaceutical lab C) determination of the cause of cancer in a patient D) formulation of a vaccine against a new pathogen in a genetic engineering lab E) whenever the scientific method is used to investigate a microbiological problem Answer: A
B. Anthrax
29) Robert Koch identified the cause of A) smallpox. B) anthrax. C) diphtheria. D) AIDS. E) tuberculosis.
D. Pathogen
3) The term used to describe a disease-causing microorganism is A) microbe. B) bacterium. C) virus. D) pathogen. E) infection.
typical natural environment pH for microbes
3-9 (but outliers exist)
Microbial cells first evolved on Earth approximately ________ billion years ago.
3.8 to 4.3
C. Ehrlich
33) Who was the first scientist to pursue a magic bullet modern chemotherapy (antibiotics) that could be used to treat infectious disease? A) Jenner B) Pasteur C) Ehrlich D) Lister E) Semmelweis
E. DNA resulting when genes from one organism and inserted into another organism
36) Recombinant DNA refers to the A) study of bacterial ribosomes. B) study of the function of genes. C) interaction between human and bacterial cells. D) synthesis of proteins from genes. E) DNA resulting when genes from one organism are inserted into another organism.
Answer: TRUE
4) Anton van Leeuwenhoek was the first microbiologist to use a microscope to examine environmental samples for the presence of microorganisms.
E. riboflavin, acetone and insulin
4) Common commercial benefits of microorganisms include synthesis of A) riboflavin. B) acetone. C) insulin. D) aspirin. E) riboflavin, acetone and insulin.
A. Compared to free-living bacteria, biofilms are more sensitive to antibiotics.
43) Which of the following statements about biofilms is FALSE? A) Compared to free-living bacteria, biofilms are more sensitive to antibiotics. B) Biofilms in pipes can block the flow of water. C) Biofilms in your body protect mucous membranes from harmful microbes. D) Biofilms on medical devices cause infections. E) Biofilms on rocks provide food for animal life
A. enzymes
5) Commercial utilization of microbial products has become increasingly popular due to their environmentally friendly nature. Production of these products which are readily degraded and, thus, non-toxic typically utilizes A) enzymes. B) organic acids. C) organic solvents. D) soap. E) alcohol.
Answer: FALSE
5) Spontaneous generation refers to living cells arising only from other living cells.
Answer: TRUE
6) Microbes are associated with life-sustaining benefits as well as life-threatening diseases.
D. Carolus Linnaeus
6) The formal system for classifying and naming organisms was developed by A) Robert Koch. B) Ignaz Semmelweis. C) Aristotle. D) Carolus Linnaeus. E) Louis Pasteur.
C. species
7) In the name Staphylococcus aureus, aureus is the A) genus. B) domain name. C) species. D) kingdom. E) family name.
B. a nucleus
8) A prokaryotic cell may possess each of the following cellular components EXCEPT A) flagella. B) a nucleus. C) ribosomes. D) a cell wall. E) a cell membrane.
A. organelles
9) Which of the following is NOT associated with viruses? A) organelles B) nucleic acid C) envelope D) chemical reactions E) protein coat
Exponential phase (also called logarithm phase)
??? Phase -cells in this phase are typically healthiest
Stationary phase
??? Phase -growth rate of population is zero -either an essential nutrient used up or waste products accumulate -metabolism continues at a greatly reduced rate -some cells grow while others die, balancing each other
Death phase
??? Phase -if incubation continues after cells reach stationary phase, the cells will eventually die -rate is exponentially regressing (slower than exponential growth) -cells can still remain viable for months or years
Lag phase
??? Phase -interval between inoculation of a culture and beginning of growth -time needed for biosynthesis of new enzymes (gene expression required) and to produce required metabolite before growth can begin
A Pasteur flask has a(n) A) swan neck to prevent particulate matter from getting into the main body of the flask. B) double neck so two substances may be added at the same time. C) secondary opening at the base to allow for drainage. D) inverted upper edge to prevent spillage while swirling.
A
Bioremediation ________ by introducing pollutant-consuming microorganisms or specific nutrients that help microorganisms degrade pollutants. A) accelerates the natural cleanup process B) exploits genetic exchange mechanisms C) invokes microbial evolution D) uses chemotaxis of biodegrading microorganisms
A
Major classes of macromolecules present in all living microorganisms include A) amino acids, carbohydrates, lipids, and nucleic acids. B) cell wall, cytoplasmic membrane, nucleoid, and ribosomes. C) genes, proteins, and vitamins. D) inorganic and organic compounds.
A
Regarding early life on Earth, A) microbial life existed for billions of years before plant and animal life. B) microbial life existed long before animals but has been around for about the same amount of time as plants. C) microbial life, plant life, and animal life all appeared at about the same time. D) it is impossible to determine which type of life first appeared.
A
Some microorganisms can undergo ________ in which various cell types can become specialized and arise from one parent cell type. A) differentiation B) genetic exchange C) maturation D) mutagensis
A
The discovery of antibiotics and other important chemicals led to the field of A) industrial microbiology. B) agricultural microbiology. C) marine microbiology. D) aquatic microbiology.
A
The largest mass of living material on Earth comes from A) microorganisms. B) plants. C) animals. D) plants and animals together.
A
The theory of spontaneous generation was refuted by the work of A) Louis Pasteur. B) Robert Koch. C) Robert Hooke. D) Antoni van Leeuwenhoek.
A
Transparent double-sided dishes used for growing microbes are most commonly called A) Petri dishes. B) baker dishes. C) sterilization plates. D) culture medium plates.
A
amphitrichous flagella
A single flagellum (or multiple flagella; see below) can extend from both ends of the cell
Viruses
Acellular Consist of DNA or RNA core Core is surrounded by a protein coat Coat may be enclosed in a lipid envelope Are replicated only when they are in a living host cell Inert outside living hosts
Ignaz Semmelweis
Advocated handwashing to prevent transmission of puerperal fever from one obstetrical patient to another
Compare and contrast the works of Louis Pasteur and Robert Koch in terms of both applied techniques and basic science.
Answers will vary, but should highlight the differences between basic scientific research in which fundamental ideas are discovered opposed to the usage of microbiological principles to solve larger questions. Examples of Pasteur's basic science contributions are his work showing that fermentation was mediated by microorganisms and the preferential metabolism of particular optical isomers by microbes. Pasteur also applied his ideas to develop sterilization techniques. Robert Koch focused more on the application of microbiology to identify the cause of tuberculosis by developing pure culturing techniques and the four postulates to link microbes to a disease.
How would the presence of endospores in Louis Pasteur's nutrient solutions have affected his conclusions about spontaneous generation?
Answers will vary, but ultimately this could have confounded Pasteur if the endospores sometimes went into a vegetative growth phase and other times no growth was observed.
The production of human proteins (e.g., insulin) by genetically engineered microorganisms is an example of ________, a subdiscipline of microbiology. A) applied microbiology B) biotechnology C) industrial microbiology D) molecular microbiology
B
A pure culture A) is sterile. B) is a population of identical cells. C) is made of a clearly defined chemical medium. D) contains one microbial cell.
B
An ecosystem includes ________ along with ________. A) macroorganisms / microorganisms B) living organisms / their chemical and physical environments C) pathogenic organisms / non-pathogenic organisms D) single celled organisms / multi-cellular organisms
B
Chemolithotrophy involves A) oxidation of organic compounds. B) oxidation of inorganic compounds. C) reduction of organic compounds. D) metabolic autotrophy.
B
Cyanobacteria and purple bacteria both obtain energy from light. However, only the ________ are capable of releasing ________. A) cyanobacteria / organic compounds B) cyanobacteria / oxygen C) purple bacteria / organic compounds D) purple bacteria / oxygen
B
Louis Pasteur's most famous success was his work on A) Mycobacterium tuberculosis. B) the rabies vaccine. C) optical isomers. D) cultivation of E. coli.
B
Microbes playing a role in nitrogen fixation in plants live in ________, while those playing a role in the digestive tract of certain herbivores live in ________. A) rumens / nodules B) nodules / rumens C) nodules / fortrans D) fortrans / rumens
B
Microbial cells first evolved on Earth approximately ________ billion years ago. A) 1.6 to 1.8 B) 3.8 to 3.9 C) 5.4 to 5.6 D) 7.0 to 7.2
B
Microbial control in wastewaters would most logically be a part of A) microbial genetics. B) aquatic microbiology. C) medical microbiology. D) bacterial energetics.
B
Robert Koch received the 1905 Nobel Prize in Physiology or Medicine for A) developing a smallpox vaccination. B) identifying Mycobacterium tuberculosis as the causative agent of tuberculosis. C) making an effective rabies vaccine. D) developing a smallpox vaccination, identifying Mycobacterium tuberculosis as the causative agent of tuberculosis, and making an effective rabies vaccine.
B
The person who described the "wee animalcules" was A) Robert Hooke. B) Antoni van Leeuwenhoek. C) Louis Pasteur. D) Ferdinand Cohn.
B
Which of the following is NOT an accomplishment of Louis Pasteur? A) determined that the alcohol-making process was mediated by microbial fermentation and thus refuted the theory of spontaneous generation B) developed enrichment culture techniques C) developed heat sterilization techniques that involved the creation of a specialized swan-necked flask D) developed the first rabies vaccine and treated thousands of individuals
B
Which of the following is/are characteristic of ALL cellular organisms? A) communication B) evolution C) motility D) communication, evolution, and motility
B
Which statement is TRUE? A) Populations are assemblages of microbial communities. B) Microbial communities are assemblages of populations. C) Habitats are assemblages of microbial communities. D) Populations are assemblages of habitats.
B
Bacillus anthracis deficient in its ability to differentiate would not be able to A) chemotax towards growth substrates. B) create vessicles. C) form endospores. D) grow without additional supplemented nutrients.
C
The disease anthrax is caused by the pathogenic bacterium ________, which produces heat- resistant structures known as ________.
Bacillus anthracis / endospores
Fannie Hesse is credited with giving ________ the idea to use agar as a solidifying agent. A) Louis Pasteur B) Ferdinand Cohn C) Robert Koch D) Sergei Winogradsky
C
Groups of cells derived from a single parent cell by successive cell divisions are known as microbial ________ and which live in environments known as microbial ________. A) communities / habitats B) communities / ecosystems C) populations / habitats D) populations / ecosystems
C
Mushroom peroxidase
Bleaching method safer than chlorine and can be easily removed from fabric and wastewater by enzymes
Lazzaro Spallanzani
Boiled nutrient solutions in sealed flasks; no microbial growth - proving biogenesis
________ was the first to describe microorganisms, while ________ was the first person to see bacteria. A) Antoni van Leeuwenhoek / Robert Hook B) Antoni van Leeuwenhoek / Robert Koch C) Robert Hooke / Antoni van Leeuwenhoek D) Robert Koch / Antoni van Leeuwenhoek
C
Describe beneficial and harmful ways in which microorganisms interact with agricultural crops.
Certain microbes are beneficial to crops when they produce nutrients (e.g., NH 4+, SO42-) usable by a crop from a substrate that was unusable. Other microbes can cause diseases in plants, much like pathogens cause disease in humans.
Rudolf Virchow
Challenged the case for spontaneous generation with the concept of biogenesis
Antibiotics
Chemicals produced by bacteria and dungi to inhibit or kill other microbes
Martinus Beijerinck was the first to isolate A) green algae. B) certain nitrogen-fixing root nodule bacteria. C) certain sulfate-reducing bacteria. D) green algae, certain nitrogen-fixing root nodule bacteria, and certain sulfate-reducing bacteria.
D
Robert Koch contributed to the field of microbiology by being the first person to A) develop the tuberculin test. B) formulate four postulates for definitively linking a specific microorganism to a specific disease. C) use agar as a solidifying agent in growth media. D) develop the tuberculin test, formulate four postulates for definitively linking a specific microorganism to a specific disease, and use agar as a solidifying agent in growth media.
D
The process whereby microorganisms are used to help clean up pollution created by human activities is known as A) bioaugmentation. B) biodegradation. C) bioengineering. D) bioremediation
D
The science of grouping and classifying microorganisms is known as A) microbial physiology. B) proteomics. C) metabolomics. D) microbial systematics.
D
________ produced by microbial fermentation of glucose from cellulose or cornstarch is becoming a more important component of biofuels in the United States, and specialized ________ are needed to make this a commercially available product. A) Biodiesel / biotechnologists B) Biodiesel / industrial microbiologists C) Ethanol / biotechnologists D) Ethanol / industrial microbiologists
D
________ was the first to identify a new form of autotrophy in which energy is obtained from oxidizing inorganic compounds called ________. A) Martinus Beijerinck / heteroautotrophy B) Martinus Beijerinck / chemolithotrophy C) Sergei Winogradsky / heteroautotrophy D) Sergei Winogradsky / chemolithotrophy
D
Multicellular Animal Parasites
Eukaryotes Multicellular animals Not strictly microorganisms Parasitic flatworms and roundworms are called helminths Some microscopic stages in their life cycles
Louis Pasteur
Demonstrated that microorganisms are present in the air used S-shaped flasks Keep microbes out but let air in Broth in flasks showed no signs of life Neck of flask traps microbes Microorganisms originate in air or fluids, not mystical forces
Robert Koch
Discovered that a bacterium causes anthrax and provided the experimental steps, to demonstrate that a specific microbe causes a specific disease
Domain: Eukarya
Domain: ??? -plants, animals, fungi -first were unicellular, but now multicellular -at least six kingdoms -large diversity
Domain: Archaea
Domain: ??? -prokaryotes -less morphological diversity -mostly undifferentiated cells 1-10 micrometers long -5 well-described phylogenies -have the most extremophiles, but have non-extremophiles, too -lack known parasites or pathogens of plants/animals
Domain: Bacteria
Domain: ??? -prokaryotes -usually undifferentiated single cells 1-10 micrometers but can vary -30 major phylogenetic lineages, very diverse
Fungi
Eukaryotes Distinct nucleus Chitin cell walls Absorb organic chemicals for energy Yeasts are unicellular Molds and mushrooms are multicellular Molds consist of masses of mycelia, which are composed of filaments called hyphae
Trichoderma fungus
Enzymes used to soften and fade denim by digesting some of the cellulose in cotton
Koch's postulates
Established experimental steps for directly linking a specific microbe to a specific disease
________ produced by microbial fermentation of glucose from cellulose or cornstarch is becoming a more important component of biofuels in the United States, and specialized ________ are needed to make this a commercially available product.
Ethanol / industrial microbiologists
Protozoa
Eukaryotes Absorb or ingest organic chemicals May be motile via pseudopods, cilia, or flagella Free-living or parasitic (derive nutrients from a living host)
Algae
Eukaryotes Cellulose cell walls Found in freshwater, saltwater, and soil Use photosynthesis for energy Produce oxygen and carbohydrates
The explosive chemical trinitrotoluene (TNT) can remain in soils after use and is hazardous to humans. Propose an experiment in which TNT-degrading microorganisms could be isolated for purposes of bioremediation. Also indicate what experimental evidence would be useful to isolate TNT-degrading microorganisms.
Experimental designs will vary, but one example would be to use the enrichment culture technique with soil from an ammunition site. While adding TNT to the enrichment culture, a key piece of experimental evidence could be the loss of TNT in the culture to initiate isolation attempts.
What does it mean to have high surface area to volume.
Have more area out side the cell then inside. IE, humans have more volume over all then we do on our surface. we ingest or nutrients unlike most prokaryotic that rely on there surface area to take in nutrients and let go wast.
Edward Jenner
Inoculated a person with cowpox virus, who was then immune from smallpox Vaccination is derived from the Latin word vacca, meaning cow The protection is called immunity
Why is it important to use cultivation-independent methods to help understand microbial diversity?
It allows researchers to identify species that cannot be grown in culture.
Why is ribosomal RNA especially useful for the study of phylogenetic relationships?
It is highly conserved.
Who was the first researcher to provide direct experimental data that supported the germ theory to explain infectious disease?
Koch
The theory of spontaneous generation was refuted by the work of
Louis Pasteur
Biofilms
Microbes attach to solid surfaces and grow into masses They will grow on rocks, pipes, teeth, and medical implants Can cause infections and are often resistant to antibiotics
Which of the following statements is FALSE?
Microbial cells include both bacteria and viruses.
Which of the following statements is correct?
Microorganisms are significant contributors to the total biomass on Earth.
Which statement about the relationship between microbes and humans is FALSE?
Most microbes are pathogenic.
Predict how Pasteur's conclusions on spontaneous generation with swan flasks would have changed if he worked with and maintained the flasks in a sterile laminar flow hood.
Pasteur's flasks never would have putrefied (decayed/rotted), and the experiment would not have refuted spontaneous generation.
Why is it incorrect to say that an object is partially sterile?
Sterile means the absence of all living organisms. Something is either sterile or it is not. Other terms are used to describe objects that have been cleaned but are not sterile, such as disinfected.
A. bacillus
The bacterial shape of the cells in the scanning electron micrograph shown in Figure 1.1 would best be described as
Explain why only anaerobic bacteria inhabited Earth for the first two billion years of its existence.
The key idea is an anoxic environment will not allow aerobic organisms to survive.
Answer: FALSE
The process of pasteurization to reduce food spoilage utilizes high heat to kill all bacteria present.
what forces may be involved in setting the morphology ?
They cell may be small and have a high surface to volume ratio that helps optimize nutrient uptake, motility like swimming so it might be spiral or gliding
What type of microscope would you use to visualize the internal structures of a chloroplast? Support your answer with evidence based on the size of the structures you want to see and the resolution and magnification power of different types of microscopes.
Transmission electron microscopy would be necessary to visualize the internal structures of a chloroplast. Chloroplasts are less than 5 μm in diameter and the internal membranes are only 10 nm thick. Light microscopes only have a resolution of 200 nm, thus any structure less than 200 nm will not be visible. Individual chloroplasts could be seen with a light microscope, but not the structures inside. Scanning electron microscopy can only see external features because electrons cannot penetrate the cell, thus the cell must be sectioned and prepared for transmission electron microscopy to see the inside of the chloroplasts.
The Great Plate Count Anomaly
What it's called when direct microscopic counts of natural samples reveal far more organisms than those recoverable on plates WHY? -microscopic methods count dead cells, whereas viable methods do not -different organisms may have vastly different requirements for growth
~3.6 billion y.a.
When did the first anoxygenic phototrophs appear?
3.8-4.3 billion y.a.
When did the first cells appear on Earth?
~2.6 billion y.a.
When was O2 introduced to the Earth's atmosphere?
Bend prevented microbes from entering flask
Where were microbes not present in the flask
genome
a cell's full complement of genes
batch culture
a closed-system microbial culture of fixed volume
Bioremediation ________ by introducing pollutant-consuming microorganisms or specific nutrients that help microorganisms degrade pollutants.
accelerates the natural cleanup process
bactericidal agents
agents that bind tightly and kill bacteria cells
bacteriostatic agents
agents that inhibit biochemical processes in bacteria such as protein synthesis and bind weakly
-static agents
agents that inhibit microbe growth
bacteriolytic agents
agents that kill bacteria by lysis such as detergents
continuous culture
an open system microbial culture of fixed volume
aerotolerant anaerobes
anaerobes that can tolerate oxygen and grow in its presence even though they cannot respire it
gram-negative bacteria
appear pink when stained due to thin layer or peptidoglycan sandwiched between two lipid layers
gram-positive bacteria
appear purple-violet when stained due to a thicker layer of peptidoglycan in cells outside of their cell membranes
Microbial control in wastewaters would most logically be a part of
aquatic microbiology
cytoplasm
aqueous mixture of macromolecules, small organics, ions, and ribosomes inside the cell
zone of inhibition
area of NO GROWTH around filter disc in disc infusion assay
bioremediation
area of microbe use that cleans up pollutants
biotechnology
area of microbe use that genetically engineers microbes, making high-value products in very small amounts
dynein
attached to microtubules and uses ATP to drive motility
cytoplasmic (cell) membrane
barrier that separates the inside of the cell from the outside environment
binary fission
cell division following enlargement of a cell to twice its minimum size
morphology
cell shape
The structure that confers structural strength on the cell is known as the
cell wall
pure cultures
cells from only a single type of microorganism
culture
cells grown in/on nutrient medium
reducing agents
chemicals added to culture media to reduce oxygen content (ex. thioglycolate broth)
antimicrobial agents
chemicals that kill or inhibit growth
Louis Pasteur
chemist and microscopist -discovered living organisms discriminate between optical isomers -discovered alcoholic fermentation was a biologically (not just chemically) mediated process (from yeast) -disproved spontaneous generation -developed vaccines for anthrax, fowl cholera, and rabies
complex media
class of media composed of digests of microbial animal or plant products (ex. yeast and meat extracts)
defined media
class of media where the exact chemical composition is known
lysosomes
clean up waste in cells and use enzymes to dispose of them
turbidity
cloudiness (can occur in samples because cells scatter light); measured by a spectrophotometer
aseptic technique
collection of practices that allow preparation and maintenance of sterile chemicals
When medical devices are left in the body, bacteria may grow on them as ________, which makes them especially resistant to treatment.
communities
sporulation cycle
complex series of events; for over 200+ sprore-specific genes
disinfection
directly targets the removal of all pathogens, not necessarily all microorganisms
T/F All microorganisms require molecular oxygen to carry on life functions.
false
T/F Differentiation occurs only in multicellular organisms.
false
T/F Most microorganisms are pathogenic.
false
matrix
innermost area of mitochondrion; contains acid enzymes
cytoskeleton
internal cell structural support
A pure culture
is a population of identical cells
What does the morphology of an organism tell you?
it doesn't help predict physiology, ecology, phylogeny or other properties of a prokaryotic cell but it might tell you about it environment.
Mycobacterium tuberculosis is very difficult to stain because of the
large amounts of a waxlike lipids present in its cell wall
LUCA
last universal common ancestor
medium
liquid/solid mixture containing all required nutrients
cell
living compartment that interacts with the environment and other cells
microbial mats
multilayered sheets with different organisms in each layer (ex. hot springs, intertidal regions)
cell inclusions
not a true organelle, but help cells save materials for later if able -energy reserves -carbon reserves -enclosed by thin membrane -reduce osmotic stress
sterile
no living organisms present
Microbes playing a role in nitrogen fixation in plants live in ________, while those playing a role in the digestive tract of certain herbivores live in ________.
nodules / rumens
mitosis
normal form of nuclear division in eukaryotic cells; results in two diploid daughter cells
necessary intracellular pH for microbes
pH 6-9
septum
partition between dividing cells; pinches off between two daughter cells
mycoplasms
pathogenic bacteria related to gram-positive bacteria, but do not have cell walls
Transparent double-sided dishes used for growing microbes are most commonly called
petri dishes
Which of the following types of microscopy is especially effective for viewing details of internal structures within live cells?
phase-contrast microscopy
Robert Koch
physician and microbiologist -demonstrated link between microbes and infectious diseases -identified causative agents of anthrax, tuberculosis, and cholera -proposed postulates for telling if a pathogen was a causative agent -developed solid media for obtaining pure cultures -won Nobel Prize for Physiology and Medicine
Electron microscopy has greater ________ than light microscopy, because the wavelength of visible light is much larger than the wavelength of electrons.
resolution
scotophobotaxis
response involving entering darkness, cells subsequently tumbling, reversing direction, and heading back toward light
aerotaxis
response to oxygen
hydrotaxis
response to water
budding division
results from unequal cell growth and forms totally new daughter cell (also similarly involve stalks, hyphae, appendages, polar growth without differentiation of cell size)
minimum inhibitory concentration (MIC)
smallest amount of an agent needed to inhibit growth of a microorganism
colony-forming units
source of error in plating where clumps are reported instead of actual number of viable cells
meiosis
specialized form of nuclear division; results in four haploid gametes
coccus
spherical or ovoid shape
golgi complex
stacks of cisternae that function in concert with the ER (modifies products of ER destined for secretion)
differential stains
stains where different cells become different colors
flagella/archaella
structure that assists in swimming in Bacteria and Archaea, respectively (tiny rotating machines)
microbial diversity
study of microbes that focusses on non-medical aspects of microbiology in soil and water
pseudomurein
substance found in cell walls of certain methanogenic archaea; polysaccharide similar to peptidoglycan -penicillin and lysozyme would not work on these
ecosystem
term that refers to all living organisms plus physical and chemical constituents of their environment
phase ring
used in phase-contrast microscopy; amplifies differences in the refractive index of cell and surroundings
A Pasteur flask has a(n)
swan neck to prevent particulate matter from getting into the main body of the flask.
enrichment culture technique
technique that says microbes can be isolated from natural samples in a highly selective fashion by manipulating nutrient and incubation conditions (ex. nitrogen-fixing bacteria)
viable plate counts
the measurement of a living, reproducing population
Pasteurization
the process of using precisely controlled heat to reduce the microbial load in heat-sensitive liquids (does not kill ALL organisms, so different from sterilization)
Louis Pasteur's most famous success was his work on
the rabies vaccine
decontamination
the treatment of an object to make it safe to handle
phylogenetic stains
these can determine proportion of Bacteria and Archaea in a sample
chemoreceptors
these can sense attractants and repellants based on chemicals in an environment
microtubules
these filaments of cytoskeleton maintain cell shape and motility; move chromosomes and organelles (a & b tubulin)
intermediate filaments
these filaments of cytoskeleton that maintain cell shape and position of organelles (keratin proteins)
microfilaments
these filaments of cytoskeleton that maintain cell shape; involved in amoeboid motility and cell division (actin)
buffers
these help microbes maintain constant pH (like in yogurt or pickling things)
cryoprotectants
these prevent formation of ice crystals (ex. antifreeze, some solutes)
Which of the following types of microscopy could be used to visualize the layers of the cell membrane and the cell wall?
transmission electron microscopy
prokaryotes
type of cell: some Bacteria and Archaea, have no membrane-enclosed organelles; no nucleus
eukaryotes
type of cell: some plants, animals, algae, protozoa, fungi; contains organelles; has DNA-enclosed in a membrane-bound nucleus
linear chromosomes (and many more, up to billions of base pairs)
typical eukaryotic DNA shape
circular chromosomes that aggregate in the nucleoid region
typical prokaryotic DNA shape
polyhydroxyalkanoate (PHA)
use to make plastic