____ first described bacterial cells in a 1684 manuscript by referring to them as "wee animalcules."
Antoni van Leewenhoek
______ developed the culturing technique to enrich for a certain population of microbial cells.
____first to reveal how certain bacteria can obtain energy from inorganic compounds.
What are 4 postulates of Robert Koch? What was his greatest accomplishment in the field of medicine?
1. The disease-causing organism must always be present in animals suffering from the disease but not in healthy animals.
2. The organism must be cultivated in a pure culture away from the body
3. The isolated organism must cause the disease when inoculated into healthy susceptible animals.
4. The organism must be isolated from the newly infected animals and cultured again in the laboratory, after which it should be seen to be the same as the original organism.
-->His discovery of the causative agent of tuberculosis.
-->He developed techniques (solid media) for obtaining pure cultures of microbes. Some are still in existence today.
How do nodule-forming bacteria help agriculture?
A number of major crop plants are legumes. Legumes live in close association with bacteria that form structures called nodules on their roots. In the root nodules, these bacteria convert atmospheric nitrogen (N2) into ammonia (NH3) that the plants use as a nitrogen source for growth.
What is bioremediation?
Role of microbes in cleaning up pollutants to produce commercially valuable products by industrial microbiology and biotechnology
Frederick Sanger received Nobel Prize for which of their work in _____
structure and sequencing of proteins, DNA sequencing
What are Pasteur's contributions? Which vaccines he developed?
-Discovered that living organisms discriminate between optical isomers
-Discovered that alcoholic fermentation was a biologically mediated process (originally thought to be purely chemical)
-Disproved theory of spontaneous generation
-Led to the development of methods for controlling the growth of microorganisms (aseptic technique)
-Developed vaccines for anthrax, fowl cholera, and rabies
Why is Mycobacterium tuberculosis difficult to stain?
Because of the large amounts of a waxy lipid present in its cell wall
Which statement is generally NOT true?
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.
Microbial cells include both bacteria and viruses
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.
Differential selection and reproduction of phenotypes occurs during a process called
A specific molecule, used especially by evolutionary biologists, that is unique to a particular taxonomical group is called a
Fannie Hesse is credited with giving ________ the idea to use agar as a solidifying agent
Which of the following is NOT a major ecosystem?
D) other organisms, such as plants and animals
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) Microbial communities are assemblages of populations.
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 ________.
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) developed enrichment culture techniques
A Pasteur flask has a(n)
swan neck to prevent particulate matter from getting into the main body of the flask.
Robert Koch's greatest accomplishment in the field of medical bacteriology was with
Martinus Beijerinck was the first to isolate
A) green algae.
B) certain nitrogen-fixing root nodule bacteria.
C) certain sulfate-reducing bacteria.
Developments in the fields of immunology and medical microbiology were practical extensions of the work of
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.
Mycobacterium tuberculosis is very difficult to stain because of the
large amounts of a waxy lipid present in its cell wall
Microorganisms play key roles in the cycling of important nutrients in plant nutrition, particularly those of
C, N, and S
Difference between prokaryotic and eukaryotic cells
i.DNA enclosed in a membrane-bound nucleus
ii.Cells are generally larger and more complex
i.No membrane-enclosed organelles, no nucleus
ii.Generally smaller than eukaryotic cells
Types of microscopy used in research
a. Light microscopy
b. Differential Interference Contrast (DIC) Microscopy
c. Atomic Force Microscopy (AFM)
d. Confocal Scanning Laser Microscopy (CSLM)
e. Electron microscopy
i. Transmission Electron Microscopes (TEM)
ii. Scanning Electron Microscopes (SEM)
DAPI (4′,6-diamidino-2-phenylindole) is used for?
a. In Fluorescence Microscopy
i. Used to visualize specimens that fluoresce
1.Emit light of one color when illuminated with another color of light
ii. Cells fluoresce naturally (autofluorescence) or after they have been stained with a fluorescent dye like DAPI
iii. Widely used in microbial ecology for enumerating bacteria in natural samples
Which bacteria autofluorescence?
Cells that contain naturally fluorescent substances such as chlorophyll or other fluorescing components
What is the difference between autotrophy and hetrotrophy?
a. All cells require carbon as a major nutrient
i. Use carbon dioxide as their carbon source
ii. Sometimes referred to as primary producers
i. Require one or more organic molecules for their carbon source
ii. Feed directly on autotrophs or live off products produced by autotrophs
Name bacteria which are chemolithotrophs and chemoorganotrphs
i. Obtain their energy from the oxidation of organic molecules
ii. Aerobes use oxygen to obtain energy
iii. Anaerobes obtain energy in the absence of oxygen
i. Obtain their energy from the oxidation of inorganic molecules
ii. Process found only in prokaryotes
Name the bacteria that lacks cell wall?
a. Mycoplasma = major genus of pathogenic bacteria
b. Some Archaea like thermoplasma and ferroplasma
What is endosymbiotic theory?
Idea that a chemoorganotrophic bacterium and a cyanobacterium were stably incorporated into another cell type to give rise, respectively, to the mitochondria and chloroplasts of modern-day eukaryotes
What is the difference between TEM and SEM?
Transmission Electron Microscopy (TEM)
i. Electromagnets function as lenses
ii. System operates in a vacuum
iii. High magnification and resolution (0.2 nm)
iv. Enables visualization of structures at the molecular level
v. Specimen must be very thin (20-60 nm) and be stained
Scanning Electron Microscopy (SEM)
i. Specimen is coated with a thin film of heavy metal (e.g., gold)
ii. An electron beam scans the object
iii. Scattered electrons are collected by a detector and an image is produced
iv. Even very large specimens can be observed
v. Magnification range of 15×-100,000×
The Gram stain differentiates bacterial cells into gram positive and gram negative based on differences in the
cell wall structure
Organisms most likely to be found in extreme environments are (archaea, bacteria, fungi, viruses)
Which of the following organisms lives within the host cell as a means of avoiding destruction by the host's immune response?
Which statement is TRUE about the genus Natronobacterium?
A) They are halophilic and alkaliphilic.
B) They are halophilic and acidophilic.
C) They are alkaliphilic but not halophilic.
D) They are acidophilic but not halophilic.
A) They are halophilic and alkaliphilic.
In a lichen, the ________ is the phototrophic component, and the ________ provides the phototroph with an anchor and with protection from the elements
alga or cyanobacterium
Ribosomal RNA-based studies reveal that
all organisms are thought to have diverged from a common ancestral organism (LUCA) or community of organisms.
According to our present understanding, mitochondria and chloroplasts are ________ in origin.
RNA-based phylogenies have influenced which subdiscipline(s) of microbiology?
A) microbial classification
B) microbial ecology
C) clinical diagnostics
Which organism has unusual cell walls, can reassemble its chromosome after it has been damaged, and has an innate resistance to high levels of radiation?
How was it determined that mitochondria and chloroplasts of eukaryotes are actually ancestors of specific lineages of Bacteria?
The most common type of microscopy for laboratory courses in biology and microbiology is done with the ____ microscope
A tiny stylus positioned so close to a specimen that weak repulsive forces are established is used in
atomic force microscopy
If the magnification of an ocular lens of a particular microscope is 10× and the magnification of the objective on the same microscope is 47×, the total magnification achieved is
What type of microscopy has found widespread use in microbial ecology because of its ability to resolve the different layered components of a biofilm?
confocal scanning laser microscopy (CSLM)
Why is the presence of a cell wall significant from a clinical standpoint?
Animal cells do not have cell walls, so antibiotics that target cell walls can destroy invading microorganisms.
What is the difference between capsule and slime layers?
Capsules and Slime Layers
i. Polysaccharide layers
1.May be thick or thin, rigid or flexible
ii. Assist in attachment to surfaces
iii. Protect against phagocytosis
iv. Resist desiccation
Capsule = if the layer is organized in a tight matrix that excludes small particles, such as India ink
i. Typically adhere firmly to the cell wall, and some are even covalently linked to peptidoglycan
Slime layer = if the layer is more easily deformed, it will not exclude par-ticles and is more difficult to see
i. Are loosely attached and can be lost from the cell surface.
Function of lysozyme
destroys peptidoglycan by cleaving the B-1,2-glycosidic bonds between N-acteylglucosamine and N-acetylmuramic acid in peptidoglycan, thereby weakening the wall
i. Found in animal secretions including tears, saliva, and other body fluids, and functions as a major line of defense against bacterial infection
Function of autolysis
Beginning at the FtsZ ring, small gaps in the wall are made by enzymes
i. Function like lysozyme to hydrolyze the B-1,4-glycosidic bonds that connect N-acetylglucosamine and N- acetylmuramic acid in the peptidoglycan backbone
What is the composition of peptidoglycan?
i. Rigid layer that provides strength to cell wall
ii. Polysaccharide composed of
1. N-acetylglucosamine and N-acetylmuramic acid
2. Amino acids
3. Lysine or diaminopimelic acid (DAP)
4. Cross-linked differently in gram-negative bacteria and gram-positive bacteria
Translocases are responsible for?
-inserts integral membrane proteins into the membrane
What is/are the excess carbon and energy storage molecules in bacteria?
a. Glycogen granules
b. Poly-B-hydroxyalkanoate (PHA)
c. Granules of polyphosphate
An organism of the genus Staphylococcus is ________, while an organism of the genus Spirochaeta is ________.
Nutrients and waste products pass into and out of a cell in ________ proportion to the cell's size.
Sterols are virtually always present in? absent in?
present in eukaryotic membranes but absent in prokaryotic membranes
Bacteria have ____ linkages
Eukarya have ____ linkages
Archaea have _____ linkages
ester - bacteria
ester - eukarya
ether - archaea
Carrier-mediated transport is necessary when (3)
A) diffusion will not allow adequate amounts of a substance to enter the cell.
B) movement into the cell is against a concentration gradient.
C) the level of nutrients in nature is very low
The periplasm is a(n)
region between the cytoplasmic membrane and the outer membrane of gram-negative Bacteria.
The gram-positive wall contains a _____ peptidoglycan layer but is ____ complex than the gram-negative wall
_____ flagella are all over the bacterial cells
_____ flagella are tufts on the "ends" of bacterial cells
Which of the following statements is FALSE?
A) A flagellar protein subunit is flagellin.
B) In flagellar motion, the basal body acts as a motor.
C) Flagella rotate at a constant speed.
D) The hook is the wider region at the base of the flagellum.
C) Flagella rotate at a constant speed
Which of the following statements is/are TRUE?
A) Fimbriae are generally shorter and more numerous than flagella.
B) Fimbriae enable cells to stick to surfaces.
C) Pili serve as receptors and facilitate genetic exchange between prokaryotic cells.
D) All of the above are true.
all of the above
A major function of prokaryotic gas vesicles is to
confer buoyancy on cells by decreasing their density
What is the biological function of endospores?
They enable organisms to endure extremes of temperature, drying, and nutrient depletion
The tetraether molecule within the membrane structure of the ________ yields a lipid ________.
The prokaryotic transport system that involves a substrate-binding protein, a membrane-integrated transporter, and an ATP-hydrolyzing protein is
the ABC system
Negatively charged molecules that are partially responsible for the negative charge of the gram-positive bacterial cell surface are
Although the inner leaflet of the gram-negative outer membrane contains phospholipids, the outer leaflet of the outer membrane contains
One of the many types of proteins found in the cytoplasmic membrane is involved in the chemotactic response and is called a
When does endospore formation commence?
when bacterial growth ceases due to limitation of an essential nutrient