Chp. 16 - Microbial Life: Prokaryotes and Protists

Comprehensive vocabulary flashcards covering the characteristics, classification, and diversity of prokaryotes and protists as described in the lecture notes.

Prokaryotic Diameter

$$1-5\,\mu m$$

Eukaryotic Diameter

$$10-100\,\mu m$$

Prokaryotic Biomass

Estimated to be at least $10$ times greater than the collective biomass of all eukaryotes.

Prokaryotes Environmental Range

Thrive in habitats often lethal to eukaryotes, including environments that are cold, hot, salty, acidic, or alkaline.

Pathogens

Bacteria that causes disease.

Beneficial Bacteria

The hundreds of species on or in the human body that decompose dead skin cells, supply essential vitamins, and protect against pathogenic organisms.

Prokaryotes Ecological Role

Act as decomposers, recycling vital chemicals through ecosystems.

Common Shapes of Prokaryotes

Cocci, Bacilli, and Spiral

Cocci

Spherical prokaryotic cells.

Streptococci

Cocci occurring in chains.

Bacilli

Rod-shaped cells that may be thread-like.

The Two Spiral Prokaryotes

Spirilla and Spirochetes

Spirilla

Short and rigid spiral prokaryotes.

Spirochetes (Morphology)

Long and flexible spiral prokaryotes.

Prokaryote Cell Walls

Structures providing physical protection and preventing lysis in hypotonic environments.

Two Types of Gram Stains

Gram - positive and Gram - Negative

Gram-positive

Bacteria with simpler cell walls containing a relatively thick layer of peptidoglycan.

Gram-negative

Bacteria with complex cell walls containing less peptidoglycan; often more likely to be pathogenic.

Capsule

A sticky layer composed of proteins and polysaccharides that covers prokaryote cell walls, allowing adherence to substrates and protection from a host's immune system.

Flagella

Distinct structures from the eukaryotic version that enable prokaryotic movements.

Fimbriae (Pili)

Hair-like projections that allow cells to attach to surfaces or each other.

Binary Fission

The asexual reproduction method of prokaryotes that can produce a new generation within hours.

Prokaryotic Genome

Consists of one long circular chromosome containing approximately $\frac{1}{1000}$ as much DNA as a eukaryotic genome.

Prokaryote Reproduction

Asexual Reproduction via binary fission, that can produce a new generation within hours

Plasmids

Small circular DNA molecules that replicate independently of the primary chromosome and are often used for horizontal gene transfer.

Prokaryotes Genetic Variation

Spontaneous mutations allowing for rapid adaptation to environmental changes.

Endospores

Specialized dormant cells capable of surviving extreme conditions like intense heat or cold.

Phototrophs

Organisms that capture energy from sunlight.

Chemotrophs

Organisms that extract energy from chemical compounds.

Prokaryotic Nutritional Diversity

Phototrophs, Chemotrophs, Autotrophs, Heterotrophs, Photoautotrophs, Chemoautotrophs, Chemoheterotrophs

Autotrophs

Organisms that use $CO_2$ as a carbon source.

Heterotrophs

Organisms that obtain carbon from organic compounds in other organisms.

Photoautotrophs

Organisms like Oscillatoria that use sunlight for energy and $CO_2$ for carbon. Ex: Oscillatoria

Photoheterotrophs

Organisms like Rhodopseudomonas that use sunlight for energy and organic compounds for carbon. (Phodoseudomoras)

Chemoautotrophs

Organisms like rock-eating bacteria that extract energy from inorganic chemicals and use $CO_2$ for carbon. Ex: rock-eating bacteria

Chemoheterotrophs

Organisms like Bdellovibrio that use organic molecules for both energy and carbon. (Bdellouibrio)

Biofilms

Complex surface-coating colonies of one or more species with channels facilitating nutrient distribution and waste removal.

Biofilm Microbes

Communicate via chemical signals to coordinate defense and division of labor.

Bioremediation

The use of organisms to remove pollutants from soil, air, or water.

Impacts of Biofilms

Clogs pipes, corrodes industrial equipment, and causes medical infections.

Sludge Treatment

A sewage treatment method where anaerobic bacteria and archaea decompose solid matter.

Sewage Plants

Place where prokaryotes decompose organic matter

Liquid Treatment

A sewage treatment method where liquid is sprayed over a bed coated in aerobic biofilms to remove dissolved organics.

3-Domain View

The division of life into Bacteria, Archaea, and Eukarya.

Peptidoglycan

A substance present in the cell walls of Bacteria but absent in the cell walls of Archaea and Eukarya.

RNA Sequences

Bacteria have some unique domain, Archaea have some unique & some matching Eukarya, Eukarya have some unique & some matching Archaea

Extreme Halophiles

Archaea that thrive in highly saline environments.

RNA Polymerase

Bacteria have on kind that’s small and simple, Archaea and Eukarya have several complex kinds

Extreme Thermophiles

Archaea that thrive in very hot water.

Introns

Rare in bacteria, Present in some genes in Archaea, present in Eukarya

Methanogens

Archaea living in anaerobic environments (landfills, digestive tracts) that release methane as waste.

Histones

Absent in bacteria, Present in some archaea species, present in Eukarya

Proteobacteria

A domain of Gram-negative bacteria sharing specific rRNA sequences, including Thromargarita Namibiensis and Rhizobium.

Extreme environments inhabited by Archaea

Extreme halophiles, extreme thermophiles, methanogens

Gram-positive Bacteria

A highly diverse domain of bacteria including Actinomycetes in soil and Streptomyces.

Extreme Halophiles

Thrive in highly saline environments

Cyanobacteria

Bacteria known as blue-green algae that perform plant-like, oxygen-generating photosynthesis; includes Anabaena.

Chlamydias

Bacteria that are obligate intracellular parasites of eukaryotic cells; includes Chlamydia trachomatis.

Anabaena

Cyanobacteria that have specialized nitrogen-fixing cells

Spirochetes (Domain Bacteria)

Helical pathogens such as Treponema pallidum and Borrelia sp.

Chlamydia Trachomatis

Chlamydias that cause blindness and is most common STI in U.S.

Exotoxins

Extremely powerful proteins secreted by bacteria into the environment.

Endotoxins

Lipid components of the Gram-negative outer-membrane; example includes Salmonella.

Koch's Postulates

Four criteria used to prove a bacterium causes a disease, famously used for Helicobacter pylori and peptic ulcers.

Biological Weapons

Pathogens such as Bacillus anthracis, Yersinia Destis, and Clostridium botulinum.

Protists

A diverse collection of primarily unicellular eukaryotes that are not plants, animals, or fungi.

Algae

The autotrophic mode of protists.

Protozoans

The heterotrophic mode of protists that consume bacteria or other protists.

Mixotrophs

Protists that use both photosynthesis and heterotrophy.

Endosymbiont Theory

The proposal that mitochondria and chloroplasts originated as small prokaryotes living inside larger host cells.

Parasites

Heterotrophic protist derives nutrition from living hosts

Secondary Endosymbiosis

The process where an autotrophic eukaryotic protist was engulfed by a heterotrophic eukaryotic protist.

The Major Protists Supergroups

Chromalveolates, Rhizaria, Excavata, Unikota, Archaeplastids

Chromalveolates

Diatoms, Dinoflagellates, Brown Algae, Water Molds, Ciliates, Parasites

Diatoms

Unicellular algae with silica walls whose fossilized remains appear in fossil fuels.

Dinoflagellates

Marine plankton that can be autotrophs, heterotrophs, or mixotrophs.

Brown Algae

Large multicellular autotrophs like kelp

Water Molds

Unicellular heterotrophs

Ciliates

Uses cilia for movement/feeding

Parasites

Includes plasmodium which causes malaria

Rhizaria

Foraminiferans, Radiolarians,

Foraminiferans

Rhizaria that have porous calcium carbonate shells called tests.

Radiolarians

Mostly marine Rhizaria with internal silica skeletons.

Excavata

A group with modified mitochondria and anaerobic glycolysis including Giardia intestinalis, Trichomonas vaginalis, and Trypanosoma.

Unikotas

Amoebozoans o Slime Molds(Plasmodial & cellular)

Amoebozoans

Unikota featuring lobe-shaped pseudopodia.

Plasmodial Slime Molds

A type of Unikota that exists as a single multinucleate mass called a plasmodium.

Cellular Slime Molds

A type of Unikota that exists as solitary cells but swarms into a slug-like aggregate when food is scarce.

Archaepastids

Red Algae, Green Algae, Alternation of Generations

Red Algae

Multicellular Archaeplastids found in coral reefs and used for Nori and Agar.

Green Algae

Unicellular, colonial, or multicellular

Alternation of Generations

A life cycle featuring a diploid sporophyte ($2n$) and a haploid gametophyte ($1n$).

Lineages of evolved Multicellurarity

Brown Algae, Fungi&Animals, Red and Green Algae

Ancestry

Evidence suggests choanoflagellates are the closest living protist relatives of animals, which nucleariids are the closest relatives of fungi

Choanoflagellates

Protists considered the closest living relatives of animals.

Nucleariids

Protists considered the closest relatives of fungi.