MICROBIO 2 Flashcards
most common shapes of bacteria
cocci, bacilli, spiro/spiral
spherical bacterial cells
cocci/coccus
cocci divides and remain together to form pairs
diplococci/diplococcus
Long chains of cocci result when cells adhere after repeated divisions in one plane; this pattern is seen in the genera
Streptococcus, Enterococcus, and Lactococcus
divides in random planes to generate irregular grapelike clumps
Staphylococcus
often divide in two planes to form square groups of four cells called tetrads
Micrococcus
cocci divide in three planes producing cubical packets of eight cells.
Sarcina
rod shaped bacteria
bacillus/bacilli
so short and wide that they resemble cocci.
coccobacilli
are curved to form distinctive commas or incomplete spirals
vibrios
characteristically form long multinucleate filaments or hyphae that
may branch to produce a network called a mycelium
Actinomycetes
Actinomycetes characteristically form long multinucleate filaments or hyphae that
may branch to produce a network called a _____
mycelium
shaped like long rods twisted into spirals or helices; they are called ______if rigid and _____
spirilla, spirochetes
oval- to pear-shaped, produces a bud at the end of a long hypha
Hyphomicrobium
produce nonliving stalks
Gallionella
some bacteria are variable in shape and lack a
single, characteristic
pleomorphic
used for locomotion
flagella
have a thick peptidoglycan layer and no outer lipid membrane, appear blue or purple after Gram staining
gram-positive bacteria
an amphipathic phospholipid often found in
bacterial membranes.
Phosphatidylethanolamine,
are surrounded by a thin peptidoglycan cell wall, which itself is surrounded by an outer membrane containing lipopolysaccharide
Gram-negative bacteria
Selectively permeable barrier, mechanical
boundary of cell, nutrient and waste
transport, location of many metabolic
processes (respiration, photosynthesis),
detection of environmental cues for
chemotaxis
plasma membrane
Buoyancy for floating in aquatic
environments
gas vacuole
protein synthesis
ribosomes
storage of carbon, phosphate and other and other substances
inclusion bodies
localization of genetic material (DNA)
nucleoid
Buoyancy for floating in aquatic
environments
periplasmic space
Gives bacteria shape and protection from
lysis in dilute solutions
cell wall
Resistance to phagocytosis, adherence to
surfaces
capsules and slime layers
Attachment to surfaces, bacterial mating
fimbriae, pili
Survival under harsh environmental
conditions
endospore
The polar ends interact with water and are
________
hydrophilic
the nonpolar ________ends are insoluble in water and tend to associate with one another
hydrophobic
_______ are synthesized from the same precursors as steroids.
Hopanoids
many bacterial membranes do contain pentacyclic sterol-like molecules
called _____________
hopanoids
The most widely accepted current model for membrane structure is the____________ of S. Jonathan Singer and Garth Nicholson (figure 3.7)
fluid mosaic model
______________are loosely connected to the membrane and can be easily removed.
Peripheral proteins
_______________, like membrane lipids, are amphipathic; their hydrophobic regions are buried in the lipid while the hydrophilic portions project from the membrane surface
Integral proteins
are invaginations of the plasma membrane in the shape of vesicles, tubules, or
lamellae
Mesosomes
granules of organic or inorganic material that often are clearly visible in a light microscope, is present in the cytoplasmic matrix
inclusion bodies
is a polymer of glucose units
composed of long chains formed by a(1→4) glycosidic bonds and branching chains connected to them by a(1→6) glycosidic
bonds .
Glycogen
contains B-hydroxybutyrate molecules joined by ester bonds between the carboxyl and hydroxyl groups of adjacent molecules.
Poly-B -hydroxybutyrate (PHB)
Cyanobacteria have two distinctive organic inclusion bodies
CYANOPHYCIN GRANULES, CARBOXYSOMES
are composed of large polypeptides containing approximately equal amounts of the amino acids arginine and aspartic acid
Cyanophycin granules
present in many
cyanobacteria, nitrifying bacteria, and thiobacilli.
Carboxysomes
Gas vacuoles are aggregates of enormous numbers of small, hollow, cylindrical structures called
gas vesicles
_____________ or murein is an enormous polymer composed of many identical subunits.
Peptidoglycan
homogeneous cell wall of ____________ is composed primarily of peptidoglycan
gram-positive bacteria
The most abundant membrane protein is __________, a small lipoprotein covalently joined to the underlying peptidoglycan and embedded in the outer membrane by its hydrophobic end.
Braun’s lipoprotein
When the layer is well organized and not easily washed off
capsule
_________ is a zone of diffuse, unorganized
material that is removed easily
slime layer
____________ is a network of polysaccharides extending from the surface of bacteria and other cells (in this sense it could encompass both capsules and slime layers).
glycocalyx
Many gram-negative bacteria have short, fine, hairlike appendages that are thinner than flagella and not involved in motility.
fimbriae
They are genetically determined by sex factors or conjugative plasmids and
are required for bacterial mating
sex pili
The spore often is surrounded by a thin, delicate covering called the
exosporium
it lies beneath the exosporium, is composed of several protein layers, and may be fairly thick. It is impermeable and responsible for the spore’s resistance to chemicals
spore coat
it occupies as much as half the
spore volume, rests beneath the spore coat. It is made of a peptidoglycan that is less cross-linked than that in vegetative cells.
cortex
is inside the cortex and surrounds the protoplast or core
spore cell wall (or core wall)
function as storage reservoirs for phosphate, an important
component of cell constituents such as nucleic acids.
volutin granules
energy source in reaction, they appear red or a different shade of blue when stained with the blue dyes methylene blue or toluidine blue
metachromatic granules
This is the unit of the sedimentation coefficient, a
measure of the sedimentation velocity in a centrifuge; the faster
a particle travels when centrifuged,
Svedberg unit
are layered or stratified rocks,
often domed, that are formed by incorporation of mineral sediments into microbial mats
Stromatolites
3 primary domains
bacteria, archaea, eucarya
The procaryotic
chromosome is located in an irregularly shaped region called
nucleoid
bacteria that have more than one chromosome
vibrio cholerae
cytoplasm shrivels up and pulls away from the cell wall.
plasmolysis
it attacks peptidoglycan by hydrolyzing the bond that connects N-acetylmuramic acid with carbon four of N-acetylglucosamine
lysozyme
Eucaryotic organisms with primarily glycerol fatty acyl diester membrane lipids and eucaryotic rRNA belong to the
Eucarya
domain ___________ contains procaryotic cells with bacterial rRNA and membrane lipids that are primarily diacyl glycerol diesters.
Bacteria
are layered or stratified rocks,
often domed, that are formed by incorporation of mineral sediments into microbial mats
Stromatolites
3 primary groups
Bacteria, Archaea, and Eucarya
Eucaryotic organisms with primarily glycerol fatty
acyl diester membrane lipids and eucaryotic rRNA belong to the
Eucarya
contains procaryotic cells with
bacterial rRNA and membrane lipids that are primarily diacyl
glycerol diesters.
Bacteria
Procaryotes having isoprenoid glycerol diether
or diglycerol tetraether lipids in their membranes and archaeal rRNA compose the third domain,
archaea
A__________ is a population of organisms that is
distinguishable from at least some other populations within a particular taxonomic category
strain
One strain of a species is designated
as the
type strain
The development of computers has made possible the quantitative approach known as
numerical taxonomy
Organisms with great
similarity are grouped together and separated from dissimilar organisms such groups of organisms are called
phenons/phenoms
The simple matching coefficients, or other association coefficients, are then arranged to form a
similarity matrix.
, most of the ________ that have
been isolated are extremely thermophilic, and many are acidophiles and sulfur dependent
crenarchaeotes
they grow best at acid pH values and high temperatures.
thermoacidophiles
______________are strict anaerobes that obtain energy by converting CO2, H2, formate, methanol, acetate, and other compounds to
either methane or methane and CO2.
Methanogens
ability to produce methane anaerobically
methanogens
thrive in anaerobic environments rich in organic
matter: the rumen and intestinal system of animals, freshwater and
marine sediments, swamps and marshes, hot springs, anaerobic
sludge digesters, and even within anaerobic protozoa.
Methanogens
They are aerobic
chemoheterotrophs with respiratory metabolism and require
complex nutrients, usually proteins and amino acids, for growth.
extreme halophiles or halobacteria
distinguishing trait of this family is its ab solute dependence on a high concentration of NaCl
halophiles/halobacteria
one flagellum
monotrichous
one flagellum on each pole
amphitrichous
cluster of flagella at one or both sides
lophotrichous
Flagella are
spread fairly evenly over the whole surface
peritrichous
are thermoacidophiles
that lack cell walls.
Thermoplasmata
grows in refuse piles of coal mines
Thermoplasma
The phylum _________, which is thought to represent the deepest
or oldest branch of bacteria, contains one class, one order, and
five genera.
Aquificae
are both thermophilic chemolithoautotrophs, it has been suggested that the bacterial ancestor was
probably thermophilic and chemolithoautotrophic
Aquifex
and Hydrogenobacter
is an autotroph and generates energy by oxidizing donors such as hydrogen, thiosulfate, and sulfur with oxygen as the acceptor
Aquifex
3 groups of photosynthetic bacteria
the purple bacteria, the green bacteria, and the cyanobacteria
They use water as an electron donor and generate oxygen during photosynthesis.
oxygenic
photosynthesis
they are unable to
use water as an electron source, they employ reduced molecules
such as hydrogen sulfide, sulfur, hydrogen, and organic matter as
their electron source for the generation of NADH and NADPH
anoxygenic photosynthesis
major representative of
the photosynthetic green nonsulfur bacteria.
chloroflexus
a filamentous, gliding, thermophilic bacterium that often is isolated from
neutral to alkaline hot springs where it grows in the form of
orange-reddish mats, usually in association with cyanobacteria.
chloroflexus
, links the filament to its basal body and acts as a flexible coupling
hook
Movement toward chemical attractants and away from repellents is known as
chemotaxis.
