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pilus : surface appendage of some prokaryotes used for attachment to surfaces including other prokaryotes
https://openstax.org/books/biology/pages/22-key-terms
pseudopeptidoglycan : component of archaea cell walls that is similar to peptidoglycan in morphology but contains different sugars
https://openstax.org/books/biology/pages/22-key-terms
psychrophile : organism that grows at temperatures of -15 °C or lower
https://openstax.org/books/biology/pages/22-key-terms
radioresistant : organism that grows in high levels of radiation
https://openstax.org/books/biology/pages/22-key-terms
resuscitation : process by which prokaryotes that are in the VBNC state return to viability
https://openstax.org/books/biology/pages/22-key-terms
S-layer : surface-layer protein present on the outside of cell walls of archaea and bacteria
https://openstax.org/books/biology/pages/22-key-terms
serotype : strain of bacteria that carries a set of similar antigens on its cell surface, often many in a bacterial species
https://openstax.org/books/biology/pages/22-key-terms
stromatolite : layered sedimentary structure formed by precipitation of minerals by prokaryotes in microbial mats
https://openstax.org/books/biology/pages/22-key-terms
teichoic acid : polymer associated with the cell wall of Gram-positive bacteria
https://openstax.org/books/biology/pages/22-key-terms
thermophile : organism that lives at temperatures between 60–80 °C
https://openstax.org/books/biology/pages/22-key-terms
transduction : process by which a bacteriophage moves DNA from one prokaryote to another
https://openstax.org/books/biology/pages/22-key-terms
transformation : process by which a prokaryote takes in DNA found in its environment that is shed by other prokaryotes
https://openstax.org/books/biology/pages/22-key-terms
viable-but-non-culturable (VBNC) state : survival mechanism of bacteria facing environmental stress conditions
https://openstax.org/books/biology/pages/22-key-terms
zoonosis : disease that primarily infects animals that is transmitted to humans
https://openstax.org/books/biology/pages/22-key-terms
The oldest fossil evidence of eukaryotes is about 2 billion years old. Fossils older than this all appear to be prokaryotes. It is probable that today’s eukaryotes are descended from an ancestor that had a prokaryotic organization. The last common ancestor of today’s Eukarya had several characteristics, including c...
https://openstax.org/books/biology/pages/23-chapter-summary
Protists are extremely diverse in terms of their biological and ecological characteristics, partly because they are an artificial assemblage of phylogenetically unrelated groups. Protists display highly varied cell structures, several types of reproductive strategies, virtually every possible type of nutrition, and var...
https://openstax.org/books/biology/pages/23-chapter-summary
The process of classifying protists into meaningful groups is ongoing, but genetic data in the past 20 years have clarified many relationships that were previously unclear or mistaken. The majority view at present is to order all eukaryotes into six supergroups: Excavata, Chromalveolata, Rhizaria, Archaeplastida, Amoeb...
https://openstax.org/books/biology/pages/23-chapter-summary
Protists function at several levels of the ecological food web: as primary producers, as direct food sources, and as decomposers. In addition, many protists are parasites of plants and animals that can cause deadly human diseases or destroy valuable crops.
https://openstax.org/books/biology/pages/23-chapter-summary
biological carbon pump : process by which inorganic carbon is fixed by photosynthetic species that then die and fall to the sea floor where they cannot be reached by saprobes and their carbon dioxide consumption cannot be returned to the atmosphere
https://openstax.org/books/biology/pages/23-key-terms
bioluminescence : generation and emission of light by an organism, as in dinoflagellates
https://openstax.org/books/biology/pages/23-key-terms
contractile vacuole : vesicle that fills with water (as it enters the cell by osmosis) and then contracts to squeeze water from the cell; an osmoregulatory vesicle
https://openstax.org/books/biology/pages/23-key-terms
cytoplasmic streaming : movement of cytoplasm into an extended pseudopod such that the entire cell is transported to the site of the pseudopod
https://openstax.org/books/biology/pages/23-key-terms
endosymbiosis : engulfment of one cell within another such that the engulfed cell survives, and both cells benefit; the process responsible for the evolution of mitochondria and chloroplasts in eukaryotes
https://openstax.org/books/biology/pages/23-key-terms
endosymbiotic theory : theory that states that eukaryotes may have been a product of one cell engulfing another, one living within another, and evolving over time until the separate cells were no longer recognizable as such
https://openstax.org/books/biology/pages/23-key-terms
hydrogenosome : organelle carried by parabasalids (Excavata) that functions anaerobically and outputs hydrogen gas as a byproduct; likely evolved from mitochondria
https://openstax.org/books/biology/pages/23-key-terms
kinetoplast : mass of DNA carried within the single, oversized mitochondrion, characteristic of kinetoplastids (phylum: Euglenozoa)
https://openstax.org/books/biology/pages/23-key-terms
mitosome : nonfunctional organelle carried in the cells of diplomonads (Excavata) that likely evolved from a mitochondrion
https://openstax.org/books/biology/pages/23-key-terms
mixotroph : organism that can obtain nutrition by autotrophic or heterotrophic means, usually facultatively
https://openstax.org/books/biology/pages/23-key-terms
pellicle : outer cell covering composed of interlocking protein strips that function like a flexible coat of armor, preventing cells from being torn or pierced without compromising their range of motion
https://openstax.org/books/biology/pages/23-key-terms
phagolysosome : cellular body formed by the union of a phagosome containing the ingested particle with a lysosome that contains hydrolytic enzymes
https://openstax.org/books/biology/pages/23-key-terms
plankton : diverse group of mostly microscopic organisms that drift in marine and freshwater systems and serve as a food source for larger aquatic organisms
https://openstax.org/books/biology/pages/23-key-terms
plastid : one of a group of related organelles in plant cells that are involved in the storage of starches, fats, proteins, and pigments
https://openstax.org/books/biology/pages/23-key-terms
raphe : slit in the silica shell of diatoms through which the protist secretes a stream of mucopolysaccharides for locomotion and attachment to substrates
https://openstax.org/books/biology/pages/23-key-terms
test : porous shell of a foram that is built from various organic materials and typically hardened with calcium carbonate
https://openstax.org/books/biology/pages/23-key-terms
Fungi are eukaryotic organisms that appeared on land more than 450 million years ago. They are heterotrophs and contain neither photosynthetic pigments such as chlorophyll, nor organelles such as chloroplasts. Because fungi feed on decaying and dead matter, they are saprobes. Fungi are important decomposers that releas...
https://openstax.org/books/biology/pages/24-chapter-summary
Chytridiomycota (chytrids) are considered the most primitive group of fungi. They are mostly aquatic, and their gametes are the only fungal cells known to have flagella. They reproduce both sexually and asexually; the asexual spores are called zoospores. Zygomycota (conjugated fungi) produce non-septated hyphae with ma...
https://openstax.org/books/biology/pages/24-chapter-summary
Fungi have colonized nearly all environments on Earth, but are frequently found in cool, dark, moist places with a supply of decaying material. Fungi are saprobes that decompose organic matter. Many successful mutualistic relationships involve a fungus and another organism. Many fungi establish complex mycorrhizal asso...
https://openstax.org/books/biology/pages/24-chapter-summary
Fungi establish parasitic relationships with plants and animals. Fungal diseases can decimate crops and spoil food during storage. Compounds produced by fungi can be toxic to humans and other animals. Mycoses are infections caused by fungi. Superficial mycoses affect the skin, whereas systemic mycoses spread through th...
https://openstax.org/books/biology/pages/24-chapter-summary
Fungi are important to everyday human life. Fungi are important decomposers in most ecosystems. Mycorrhizal fungi are essential for the growth of most plants. Fungi, as food, play a role in human nutrition in the form of mushrooms, and also as agents of fermentation in the production of bread, cheeses, alcoholic bevera...
https://openstax.org/books/biology/pages/24-chapter-summary
arbuscular mycorrhiza : mycorrhizal association in which the fungal hyphae enter the root cells and form extensive networks
https://openstax.org/books/biology/pages/24-key-terms
Arbuscular mycorrhizae : mycorrhizae commonly involving Glomeromycetes in which the fungal hyphae penetrate the cell walls of the plant root cells (but not the cell membranes)
https://openstax.org/books/biology/pages/24-key-terms
ascocarp : fruiting body of ascomycetes
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Ascomycota : (also, sac fungi) phylum of fungi that store spores in a sac called ascus
https://openstax.org/books/biology/pages/24-key-terms
basidiocarp : fruiting body that protrudes from the ground and bears the basidia
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Basidiomycota : (also, club fungi) phylum of fungi that produce club-shaped structures (basidia) that contain spores
https://openstax.org/books/biology/pages/24-key-terms
basidium : club-shaped fruiting body of basidiomycetes
https://openstax.org/books/biology/pages/24-key-terms
Chytridiomycota : (also, chytrids) primitive phylum of fungi that live in water and produce gametes with flagella
https://openstax.org/books/biology/pages/24-key-terms
coenocytic hypha : single hypha that lacks septa and contains many nuclei
https://openstax.org/books/biology/pages/24-key-terms
commensalism : symbiotic relationship in which one member benefits while the other member is not affected
https://openstax.org/books/biology/pages/24-key-terms
Deuteromycota : former form phylum of fungi that do not have a known sexual reproductive cycle (presently members of two phyla: Ascomycota and Basidiomycota)
https://openstax.org/books/biology/pages/24-key-terms
ectomycorrhiza : mycorrhizal fungi that surround the roots with a mantle and have a Hartig net that extends into the roots between cells
https://openstax.org/books/biology/pages/24-key-terms
Ectomycorrhizae : mycorrhizae in which the fungal hyphae do not penetrate the root cells of the plant
https://openstax.org/books/biology/pages/24-key-terms
faculative anaerobes : organisms that can perform both aerobic and anaerobic respiration and can survive in oxygen-rich and oxygen-poor environment
https://openstax.org/books/biology/pages/24-key-terms
Glomeromycota : phylum of fungi that form symbiotic relationships with the roots of trees
https://openstax.org/books/biology/pages/24-key-terms
haustoria : modified hyphae on many parasitic fungi that penetrate the tissues of their hosts, release digestive enzymes, and/or absorb nutrients from the host
https://openstax.org/books/biology/pages/24-key-terms
heterothallic : describes when only one mating type is present in an individual mycelium
https://openstax.org/books/biology/pages/24-key-terms
homothallic : describes when both mating types are present in mycelium
https://openstax.org/books/biology/pages/24-key-terms
hypha : fungal filament composed of one or more cells
https://openstax.org/books/biology/pages/24-key-terms
karyogamy : fusion of nuclei
https://openstax.org/books/biology/pages/24-key-terms
lichen : close association of a fungus with a photosynthetic alga or bacterium that benefits both partners
https://openstax.org/books/biology/pages/24-key-terms
mold : tangle of visible mycelia with a fuzzy appearance
https://openstax.org/books/biology/pages/24-key-terms
mycelium : mass of fungal hyphae
https://openstax.org/books/biology/pages/24-key-terms
mycetismus : ingestion of toxins in poisonous mushrooms
https://openstax.org/books/biology/pages/24-key-terms
mycology : scientific study of fungi
https://openstax.org/books/biology/pages/24-key-terms
mycorrhiza : mutualistic association between fungi and vascular plant roots
https://openstax.org/books/biology/pages/24-key-terms
mycorrhizae : a mutualistic relationship between a plant and a fungus. Mycorrhizae are connections between fungal hyphae, which provide soil minerals to the plant, and plant roots, which provide carbohydrates to the fungus
https://openstax.org/books/biology/pages/24-key-terms
mycosis : fungal infection
https://openstax.org/books/biology/pages/24-key-terms
mycotoxicosis : poisoning by a fungal toxin released in food
https://openstax.org/books/biology/pages/24-key-terms
obligate aerobes : organisms, such as humans, that must perform aerobic respiration to survive
https://openstax.org/books/biology/pages/24-key-terms
obligate anaerobes : organisms that only perform anaerobic respiration and often cannot survive in the presence of oxygen
https://openstax.org/books/biology/pages/24-key-terms
parasitism : symbiotic relationship in which one member of the association benefits at the expense of the other
https://openstax.org/books/biology/pages/24-key-terms
plasmogamy : fusion of cytoplasm
https://openstax.org/books/biology/pages/24-key-terms
saprobe : organism that derives nutrients from decaying organic matter; also saprophyte
https://openstax.org/books/biology/pages/24-key-terms
septa : cell wall division between hyphae
https://openstax.org/books/biology/pages/24-key-terms
soredia : clusters of algal cells and mycelia that allow lichens to propagate
https://openstax.org/books/biology/pages/24-key-terms
sporangium : reproductive sac that contains spores
https://openstax.org/books/biology/pages/24-key-terms
spore : a haploid cell that can undergo mitosis to form a multicellular, haploid individua
https://openstax.org/books/biology/pages/24-key-terms
thallus : vegetative body of a fungus
https://openstax.org/books/biology/pages/24-key-terms
yeast : general term used to describe unicellular fungi
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Zygomycota : (also, conjugated fungi) phylum of fungi that form a zygote contained in a zygospore
https://openstax.org/books/biology/pages/24-key-terms
zygospore : structure with thick cell wall that contains the zygote in zygomycetes
https://openstax.org/books/biology/pages/24-key-terms
Land plants acquired traits that made it possible to colonize land and survive out of the water. All land plants share the following characteristics: alternation of generations, with the haploid plant called a gametophyte, and the diploid plant called a sporophyte; protection of the embryo, formation of haploid spores ...
https://openstax.org/books/biology/pages/25-chapter-summary
Green algae share more traits with land plants than other algae, according to structure and DNA analysis. Charales form sporopollenin and precursors of lignin, phragmoplasts, and have flagellated sperm. They do not exhibit alternation of generations.
https://openstax.org/books/biology/pages/25-chapter-summary
Seedless nonvascular plants are small, having the gametophyte as the dominant stage of the lifecycle. Without a vascular system and roots, they absorb water and nutrients on all their exposed surfaces. Collectively known as bryophytes, the three main groups include the liverworts, the hornworts, and the mosses. Liverwo...
https://openstax.org/books/biology/pages/25-chapter-summary
Vascular systems consist of xylem tissue, which transports water and minerals, and phloem tissue, which transports sugars and proteins. With the development of the vascular system, there appeared leaves to act as large photosynthetic organs, and roots to access water from the ground. Small uncomplicated leaves are micr...
https://openstax.org/books/biology/pages/25-chapter-summary
The seedless vascular plants include club mosses, which are the most primitive; whisk ferns, which lost leaves and roots by reductive evolution; and horsetails and ferns. Ferns are the most advanced group of seedless vascular plants. They are distinguished by large leaves called fronds and small sporangia-containing st...
https://openstax.org/books/biology/pages/25-chapter-summary
Mosses play an essential role in the balance of the ecosystems; they are pioneering species that colonize bare or devastated environments and make it possible for a succession to occur. They contribute to the enrichment of the soil and provide shelter and nutrients for animals in hostile environments. Mosses and ferns ...
https://openstax.org/books/biology/pages/25-chapter-summary
adventitious : describes an organ that grows in an unusual place, such as a roots growing from the side of a stem
https://openstax.org/books/biology/pages/25-key-terms
antheridium : male gametangium
https://openstax.org/books/biology/pages/25-key-terms
archegonium : female gametangium
https://openstax.org/books/biology/pages/25-key-terms
capsule : case of the sporangium in mosses
https://openstax.org/books/biology/pages/25-key-terms
charophyte : other term for green algae; considered the closest relative of land plants
https://openstax.org/books/biology/pages/25-key-terms
club mosses : earliest group of seedless vascular plants
https://openstax.org/books/biology/pages/25-key-terms
diplontic : diploid stage is the dominant stage
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embryophyte : other name for land plant; embryo is protected and nourished by the sporophyte
https://openstax.org/books/biology/pages/25-key-terms
extant : still-living species
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extinct : no longer existing species
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fern : seedless vascular plant that produces large fronds; the most advanced group of seedless vascular plants
https://openstax.org/books/biology/pages/25-key-terms
gametangium : structure on the gametophyte in which gametes are produced
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gemma : (plural, gemmae) leaf fragment that spreads for asexual reproduction
https://openstax.org/books/biology/pages/25-key-terms