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