BIOL 1108: Prokaryotes, Early Eukaryotes, and Fungi Review

Comprehensive vocabulary flashcards covering prokaryotic diversity (bacteria and archaea), horizontal gene transfer, extremophiles, early eukaryotic diversity, endosymbiosis, protist life cycles, and fungal phyla.

Antoni van Leeuwenhoek

Known as the Father of Microbiology, he hand-crafted single-lens microscopes capable of $270\times$ magnification and discovered bacteria and protists in 1674, calling them animalcules.

Louis Pasteur

French scientist who disproved spontaneous generation using swan-neck flasks in 1859, establishing that microorganisms originate from environmental sources rather than non-living matter.

Koch's Postulates

A four-step experimental method established by Robert Koch to definitively demonstrate that a specific microorganism is the causative agent of a specific disease.

Gram Staining

A differential staining technique created by Hans Christian Gram that categorizes bacteria into Gram-positive (purple) or Gram-negative (pink) based on cell wall composition.

Peptidoglycan

A strong, flexible polymer found in bacterial cell walls made of repeating alternating units of NAG ($N$-acetylglucosamine) and NAM ($N$-acetylmuramic acid) connected by tetrapeptide crossbridges.

Gram-Positive Bacterial Cell Wall

A cell wall structure featuring a thick layer of peptidoglycan containing teichoic and lipoteichoic acids, lacking an outer membrane, and retaining crystal violet to stain purple.

Gram-Negative Bacterial Cell Wall

A complex cell wall featuring a thin layer of peptidoglycan inside a periplasmic space, surrounded by an outer membrane containing lipopolysaccharides (LPS), staining pink in the Gram procedure.

Archaea

A domain of prokaryotic organisms whose cell walls lack peptidoglycan, whose plasma membranes feature ether-linked lipids with branched hydrocarbon chains, and which frequently inhabit extreme environments.

Extremophile

An organism that is specialized to survive and thrive in physical or chemical conditions that are lethal to most other life forms.

Halophile

An extremophile optimized to grow in hypersaline conditions, typically requiring salt concentrations of $2\text{--}5\,M\text{ NaCl}$.

Thermophile

An extremophile that thrives at elevated temperatures ranging between $60^\circ\text{C}$ and $80^\circ\text{C}$.

Capsule

A highly organized, firmly bound gelatinous glycocalyx layer that enhances bacterial virulence by protecting the cell against host phagocytosis and immune detection.

Slime Layer

A diffuse, water-soluble, and loosely attached glycocalyx that aids bacteria in surface adherence and biofilm formation.

Endospore

A dormant, non-reproductive, and highly resistant survival cell produced inside certain bacterial species in response to adverse environmental conditions.

Binary Fission

The primary asexual reproductive process in prokaryotes where a single cell elongates, replicates its circular DNA, and divides into two identical daughter cells via a cytoskeletal FtsZ ring.

Autotroph

An organism that utilizes inorganic carbon dioxide ($CO_2$) as its sole carbon source to produce organic compounds.

Heterotroph

An organism that obtains carbon by ingesting or absorbing pre-existing organic molecules.

Phototroph

An organism that converts light energy into cellular ATP through photosynthesis.

Chemotroph

An organism that extracts energy from the oxidation of chemical compounds, either organic or inorganic.

Lithotroph

An organism that utilizes inorganic substances, such as $H_2$, $Fe^{2+}$, or $S$, as electron donors in metabolic pathways.

Horizontal Gene Transfer (HGT)

The non-reproductive transfer of genetic material between non-offspring organisms, facilitating rapid evolutionary adaptations across different bacterial strains.

Transformation

A mode of horizontal gene transfer where a competent bacterial cell directly absorbs free DNA fragments from its surrounding environment.

Transduction

A viral-mediated form of horizontal gene transfer in which a bacteriophage mistakenly packages host bacterial DNA and delivers it into a new host cell.

Conjugation

A contact-dependent horizontal gene transfer mechanism where genetic material passes directly from a donor bacterium to a recipient cell through a sex pilus.

Bernard Davis's U-Tube Experiment

A 1950 experiment using a U-shaped apparatus with a central membrane filter, demonstrating that direct cell-to-cell physical contact is strictly required for bacterial conjugation.

Nitrogen Fixation

The biological process in which specialized prokaryotes convert atmospheric dinitrogen gas ($N_2$) into biologically accessible ammonia ($NH_3$).

Bioremediation

The deliberate application of naturally occurring bacteria to break down or clean up environmental pollutants and toxic waste.

Endosymbiotic Theory

The theory championed by Lynn Margulis proposing that eukaryotic mitochondria and chloroplasts originated as free-living aerobic and photosynthetic bacteria that were engulfed by ancestral host cells.

Secondary Endosymbiosis

An evolutionary event where a heterotrophic eukaryote engulfs another eukaryotic cell that already possesses a primary endosymbiotic plastid.

Phagotrophy

A heterotrophic feeding mechanism where single-celled organisms ingest solid food particles or organisms via phagocytosis.

Osmotrophy

A nutritional strategy in which organisms absorb small, dissolved organic compounds directly across the cell membrane.

Mixotrophy

A metabolic strategy enabling an organism to switch between or simultaneously utilize photoautotrophy and heterotrophy (phagotrophy/osmotrophy) based on environmental conditions.

Zygotic Life Cycle

A haploid-dominant life cycle in which the vegetative organism is haploid ($N$) and the diploid zygote ($2N$) immediately undergoes meiosis.

Sporic Life Cycle

Also called alternation of generations, a life cycle characterized by alternating multicellular haploid gametophyte ($N$) and multicellular diploid sporophyte ($2N$) generations.

Gametic Life Cycle

A diploid-dominant life cycle where the multicellular body is diploid ($2N$) and the only haploid ($N$) phase consists of unicellular gametes produced by meiosis.

Chlorophyta

The phylum of green algae containing chlorophylls $a$ and $b$, storing energy as starch, and representing the closest algal relatives of land plants.

Rhodophyta

The phylum of multicellular red algae whose accessory pigment phycoerythrin absorbs blue light, enabling them to thrive in deeper marine waters.

Phaeophyta

The phylum of multicellular brown algae containing fucoxanthin and chlorophylls $a$ and $c$, storing carbohydrates as laminarin, and including giant kelps.

Diatoms

Unicellular photosynthetic phytoplankton characterized by silica ($SiO_2$) cell walls called frustules that consist of two overlapping valves.

Chitin

A tough, nitrogen-containing polysaccharide that forms the structural cell walls of fungi and the exoskeletons of arthropods.

Mycelium

The vegetative body structure of a multicellular fungus composed of a massed network of branching filaments called hyphae.

Septate Hyphae

Fungal hyphae partitioned into individual cells by internal cross-walls called septa, which contain pores for cytoplasmic movement.

Coenocytic Hyphae

Also called aseptate hyphae, fungal filaments that lack cross-walls and exist as continuous multinucleate tubes of cytoplasm.

Plasmogamy

The initial step of fungal sexual reproduction in which the cytoplasms of two compatible haploid ($N$) hyphae fuse without the immediate fusion of their nuclei.

Dikaryotic Stage

A unique fungal life cycle phase (designated $n + n$) where cells contain two distinct, coexisting haploid nuclei following plasmogamy.

Karyogamy

The step in fungal sexual reproduction where two haploid nuclei in a dikaryotic cell fuse to form a single diploid ($2N$) zygote nucleus.

Chytridiomycota

The most ancestral phylum of fungi, distinguished by aquatic habitats and the production of flagellated, motile zoospores.

Zygomycota

A phylum of terrestrial fungi with coenocytic hyphae that produce thick-walled multinucleate zygosporangia during sexual reproduction.

Glomeromycota

A phylum of obligate symbiotic fungi that form arbuscular mycorrhizae inside plant root cells to exchange nutrients with host plants.

Ascomycota

Sac fungi, the largest fungal phylum, characterized by producing sexual ascospores inside sac-like structures called asci within an ascocarp.

Basidiomycota

Club fungi, a major phylum including mushrooms and puffballs that produce sexual basidiospores on club-shaped cells called basidia.

Mycorrhizae

Mutualistic symbiotic associations between soil fungi and plant roots where the fungus increases water/mineral absorption and the plant provides carbohydrates.

Lichen

A mutualistic organism composed of a structural fungus (mycobiont) living in close partnership with a photosynthetic green alga or cyanobacterium (photobiont).