Unit 7
Nucleus
In eukaryotic cells , the large organelle containing the chromosomes and surrounded by a double membrane
Capsule
protective layer outside the cell wall of some bacteria
Symbiont
Organism in a symbiotic relationship with another organism
Coccus
a bacterium that has a spherical shape
Bacillus
a bacterium with a rod shape
Spirillum
a bacterium with a twisted shape
Staph
a group of bacterial cells arranged in a bunch
Strep
a group of bacterial cells arranged in a chain
Mixotroph
an organism that can use a mix of different sources of energy and carbon
Binary fission
asexual reproduction used by prokaryotes; used to produce two identical cells from one cell.
Extremophile
bacterium or archaean that thrives in an "extreme" environment (e.g., high-salt, high- temperature, low-temperatu
Spore
reproductive cell dispersed by a fungus during asexual and sexual reproduction
Tree of Life
A diagram depicting the genealogical relationships of all living organisms on Earth, with a single ancestral species at the base.
Plasmid
A small, usually circular, supercoiled DNA molecule independent of the cell's main chromosome(s) in prokaryotes and some eukaryotes.
Chitin
A structural polysaccharide found in cell walls of fungi and many algae, and in external skeletons of insects and crustaceans
Domain
A taxonomic category, based on similarities in basic cellular biochemistry, above the kingdom level.
Endosymbiosis
An association between species in which one lives inside the cell or cells of the other
Paraphyletic group
An evolutionary unit that includes an ancestral population and some but not all of its descendants
Saprobe
An organism that feeds primarily on dead organisms.
Parasite
An organism that lives on or in a host species and that damages its host.
Symbiosis
Any close and prolonged physical relationship between individuals of two different species
Organelle
Any discrete, membrane-bound structure within a cell (e.g., mitochondrion) that has a characteristic structure and functions
Protist
Any eukaryote that is not a green plant, animal, or fungus. Protists are diverse paraphyletic group. Most are unicellular but some are multicellular or form aggregations called colonies
Sexual Reproduction
Any form of reproduction in which genes from two parents are combined via fusion of gametes, producing offspring that are genetically distinct from both parents
Asexual reproduction
Any form of reproduction resulting in offspring that are genetically identical to the parent.
Autotroph
Any organism that can synthesize reduce organic compounds from simple inorganic sources such as CO2 or CH4. Most plants and some bacteria and archaea are autotrophs
Heterotroph
Any organism that cannot synthesize reduced organic compounds and must obtain them from eating other organisms.
Gram negative
Describing bacteria that look pink when treated with a Gram stain. These bacteria have a cell wall composed of a thin layer of peptidoglycan and an outer phospholipid layer
Gram Positive
Describing bacteria that look purple when treated with a Gram stain. These bacteria have cell walls composed of a thick layer of peptidoglycan
Fungus
A lineage of eukaryotes that typically have a filamentous body and obtain nutrients by absorption.
Cyanobacteria
A lineage of photosynthesis bacteria formerly known as blue-green algae. Likely the first life-forms to carry out oxygenic photosynthesis
Animal
A member of a major lineage of eukaryotes (Animalia) whose members typically have a complex, large, multicellular body, eat other organisms, and are mobile
Prokaryote
A member of the domain Bacteria or Archaea; a unicellular organism lacking a nucleus and organelles
Eukaryote
A member of the domain Eukarya; an organism whose cells contain a nucleus, numerous membrane-bo
Cell Wall
A protective layer located outside the plasma membrane and usually composed of polysaccharides. Not found in all cells. Found in algae, plants, bacteria, fungi, and some other groups.
Synapomorphy
A shared derived trait found in two or more taxa that is present in their most recent common ancestor but is missing in more distant ancestors. Useful for inferring evolutionary relationships
Archaea
One of the three taxonomic domains of life consisting of unicellular prokaryotes distinguished by cell walls made of certain polysaccharides not found in bacterial or eukaryotic cell walls and ribosomes and RNA polymerase similar to those of eukaryotes. Usually live in extreme environments
Bacteria
Prokaryotic organisms characterized by lack of a membrane-enclosed nucleus, predominantly unicellular
Eukarya
The domain comprised of eukaryotes (organisms whose cells contain a nucleus). an organism whose cells contain a nucleus, numerous membrane-bound organelles, and an extensive cytoskeleton. May be unicellular or multicellular.
Plant (Plantae)
The monophyletic group that includes red and green algae and land plants.
Infolding Theory]
The theory that the nuclear membrane and ER arose through infolding of the plasma membrane in an ancient cell