introduction Flashcards
studying
stromatolites
a laminated microbial mat
which can become fossilized and is typically
built from layers of filamentous
microorganisms
banded iron formation
iron oxide–rich
ancient sedimentary rocks containing
zones of oxidized iron (Fe3+) formed
by oxidation of Fe2+ by O2 produced
by cyanobacteria
phylogeny
evolutionary history
ribosomal RNA (rRNA)
RNA molecules
found in the small and large subunits of the
ribosome
recombination
resorting or rearrangement of DNA fragments resulting in a new
sequence
archaellum
a long, thin cellular appendage
present in many Archaea that rotates and is
responsible for swimming motility
basal body
the “motor” portion of the
bacterial flagellum, embedded in the
cytoplasmic membrane and cell wall
capsule
a polysaccharide or protein
outermost layer, usually rather slimy,
present on some bacteria
chemotaxis
directed movement of
an organism toward (positive chemotaxis)
or away from (negative chemotaxis) a
chemical gradient
cristae
the internal membranes of a
mitochondrion
cytoskeleton
the cellular scaffolding typical
of eukaryotic cells in which microtubules,
microfilaments, and intermediate filaments
define the cell’s shape
dipicolinic acid
a substance unique to
endospores that confers heat resistance on
these structures
endospore
a highly heat-resistant,
thick-walled, differentiated structure
produced by certain gram-positive Bacteria
gas vesicles
gas-filled cytoplasmic structures
bounded by protein and conferring
buoyancy on cells
histones
highly basic proteins that compact
and wind DNA in the nucleus of eukaryotic
cells
hydrogenosome
an organelle of
endosymbiotic origin present in certain
microbial eukaryotes that oxidizes pyruvate
to H2, CO2, and acetate, and couples this to
ATP synthesis
intermediate filament
a filamentous
polymer of fibrous keratin proteins,
supercoiled into thicker fibers, that functions
in maintaining cell shape and the positioning
of certain organelles in the eukaryotic cell
lipopolysaccharide
a combination
of lipid with polysaccharide and protein
that forms the major portion of the outer
membrane in gram-negative Bacteria
lysosome
an organelle containing digestive
enzymes for hydrolysis of proteins, fats, and
polysaccharides
magnetosome
a particle of magnetite
(Fe3O4) enclosed by a nonunit membrane in
the cytoplasm of magnetotactic Bacteria
microfilament
a filamentous polymer of
the protein actin that helps maintain the
shape of a eukaryotic cell
microtubule
a filamentous polymer of
the proteins α-tubulin and β-tubulin that
functions in eukaryotic cell shape and
motility
outer membrane
e a phospholipid- and
polysaccharide-containing unit membrane
that lies external to the peptidoglycan layer
in cells of gram-negative Bacteria
periplasm
a gel-like region between the outer
surface of the cytoplasmic membrane and
the inner surface of the lipopolysaccharide
layer of gram-negative Bacteria
peptidoglycan
a polysaccharide
composed of alternating repeats of
N-acetylglucosamine and N-acetylmuramic acid arranged in adjacent layers and
cross-linked by short peptides
peritrichous flagellation
having flagella
located in many places around the surface
of the cell
phototaxis
movement of an organism
toward light
pili
thin, filamentous structures that extend
from the surface of a cell and, depending
on type, facilitate cell attachment, genetic
exchange, or twitching motility
polar flagelation
having flagella
emanating from one or both poles of
the cell
PHB (poly beta hydroxybutyric acid)
a common storage material of prokaryotic
cells consisting of a polymer of
β-hydroxybutyrate or another β-alkanoic
acid or mixtures of β-alkanoic acids
S layer
an outermost cell surface layer
composed of protein or glycoprotein
present on some Bacteria and Archaea
stroma
the lumen of the chloroplast,
surrounded by the inner membrane
teichoic acid
a phosphorylated polyalcohol
found in the cell wall of some gram-positive
Bacteria
thylakoid
a membrane layer containing the
photosynthetic pigments in chloroplasts
