Handout 3 Flashcards
a catabolic pathway in which inorganic molecules other than oxygen accept electrons at the ‘downhill’ end of electron transport chain
anaerobic respiration
one of the five supergroups of eukaryotes proposed in a current hypothesis of the evolutionary history of eukaryotes; this monophyletic group, which includes red algae, green algae, and land plants, descended from and ancient protist ancestor that engulfed a cyanobacterium
archaeplastida
an organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. Autotrophs use energy from the sun or from oxidation of inorganic substances to make organic molecules from inroganic ones
autotroph
a method of asexual reproduction by “division in half”; in prokaryotes it
does not involve mitosis; where relevant in single-celled eukaryotes,
mitosis is part of the process.
binary fission
A surface-coating colony of one or more species of prokaryotes that
engage in metabolic co-operation.
biofilm
The use of organisms to detoxify and restore polluted and degraded
ecosystems.
bioremediation
(1) A leaf-like structure of a seaweed that provides most of the surface
area for photosynthesis. (2) The flattened portion of a typical leaf.
blade
A multicellular, photosynthetic protist with a characteristic colour that
results from carotenoids in its plastids; most are marine, and some have
a plant-like body (thallus)
brown alga
(1) In many prokaryotes, a dense and well-defined layer of
polysaccharide or protein that surrounds the cell wall and is sticky,
protecting the cell and enabling it to adhere to substrates or other cells.
(2) The sporangium of a bryophyte (moss, liverwort, or hornwort)
capsule
A protective layer external to the plasma membrane in the cells of
plants, prokaryotes, fungi, and some protists; polysaccharides such as
cellulose (in plants and some protists), chitin (in fungi), and
peptidoglycan (in bacteria) are important structural components.
cell wall
One of five supergroups of eukaryotes proposed in a current hypothesis
of the evolutionary history of eukaryotes; may have originated by
secondary endosymbiosis and include two large protist clades, the
alveolates and the stramenopiles.
chromalveolata
A short appendage containing microtubules in eukaryotic cells; a motile
version is specialized for locomotion or moving fluid past the cell; it is
formed from a core of nine outer doublet microtubules and two inner
single microtubules (the “9 + 2” arrangement) ensheathed in an
extension of the plasma membrane; a primary version is usually non-
motile and plays a sensory and signalling role; it lacks the two inner
microtubules (the “9 + 0” arrangement).
cilium
A symbiotic relationship in which one organism benefits but the other is
neither helped nor harmed.
commensalism
An organism that absorbs nutrients from non-living organic material
such as corpses, fallen plant material, and the wastes of living
organisms and converts them to inorganic forms
decomposer
A cell containing two sets of chromosomes (2n), one set inherited from
each parent
diploid cell
A protist that has modified mitochondria, two equal-sized nuclei, and
multiple flagella.
diplomonad
A thick-coated, resistant cell produced by some bacterial cells when
they are exposed to harsh conditions.
endospore
A toxic component of the outer membrane of certain gram-negative
bacteria that is released only when the bacteria die.
endotoxin
Member of a diverse clade of flagellated protists that includes
predatory heterotrophs, photosynthetic autotrophs, and pathogenic
parasites
euglenozoan
One of five supergroups of eukaryotes proposed in a current hypothesis
of the evolutionary history of eukaryotes; have unique cytoskeletal
features, and some species have an “excavated” feeding groove on one
side of the cell body.
excavata
A toxic protein that is secreted by a prokaryote or other pathogen and
that produces specific symptoms, even if the pathogen is no longer
present
exotoxin
An organism that lives in a highly saline environment, such as the Great
Salt Lake or the Dead Sea.
extreme halophile
An organism that thrives in hot environments (often 60-80°C or hotter).
extreme thermophile
An organism that lives in environmental conditions so extreme that few
other species can survive there; include “salt lovers” and “heat lovers”
extremophile
An organism that makes ATP by aerobic respiration if oxygen is present
but that switches to anaerobic respiration or fermentation if oxygen is
not present.
facultative anaerobe
A short, hair-like appendage of a prokaryotic cell that helps it adhere to
the substrate or to other cells
fimbria
A long cellular appendage specialized for locomotion; eukaryotic forms
have a core with nine outer doublet microtubules and two inner single
microtubules (the “9 + 2” arrangement) ensheathed in an extension of
the plasma membrane; prokaryotic forms have a different structure
flagellum
A bi-flagellated, photosynthetic protist named for its colour, which
results from its yellow and brown carotenoids
golden alga
Describing the group of bacteria that have a cell wall structurally more
complex and contains less peptidoglycan than the cell wall of (and are
often more toxic than) the other major type of gram-staining bacteria.
gram-negative
Describing the group of bacteria that have a cell wall structurally less
complex and contains more peptidoglycan than the cell wall of (and are usually less toxic than) the other type of major gram-staining bacteria
gram-positive
A method that distinguishes between two different kinds of bacterial
cell walls; may be used to help determine medical response to an
infection.
gram stain
A photosynthetic protist, named for green chloroplasts that are similar
in structure and pigment composition to those of land plants; they are a
paraphyletic group, some of whose members are more closely related
to land plants than they are to other members.
green alga
A cell containing only one set of chromosomes (n).
haploid cell
A specialized cell that engages in nitrogen fixation in some filamentous
cyanobacteria; also called a heterocyte.
heterocyst
A root-like structure that anchors a seaweed.
holdfast
The transfer of genes from one genome to another through
mechanisms such as transposable elements, plasmid exchange, viral
activity, and perhaps fusions of different organisms
horizontal gene transfer
The larger participant in a symbiotic relationship, often providing a
home and food source for the smaller participant.
host
Referring to a solution that, when surrounding a cell, will cause the cell
to lose water
hypertonic
Referring to a solution that, when surrounding a cell, will cause the cell
to take up water.
hypotonic
The collection and sequencing of DNA from a group of species, usually
an environmental sample of microorganisms. Computer software sorts
partial sequences and assembles them into genome sequences of
individual species making up the sample.
metagenomics
An organism that produces methane as a waste product of the way it
obtains energy; all known are in domain Archaea
methanogen
An organelle in eukaryotic cells that serves as the site of cellular
respiration; uses oxygen to break down organic molecules and
synthesize ATP
mitochondrion
An organism that is capable of both photosynthesis and heterotrophy.
mixotroph
A symbiotic relationship in which both participants benefit.
mutualism
The conversion of atmospheric nitrogen (N2) to ammonia (NH3); carried
out by certain prokaryotes, some of which have mutualistic
relationships with plants.
nitrogen fixation
A non-membrane-bounded region in a prokaryotic cell where the DNA
is concentrated.
nucleoid
An organism that requires oxygen for cellular respiration and cannot
live without it.
obligate aerobe