Final Exam Review: Microbiology, Ecology, and Conservation

Vocabulary flashcards covering microbiology, fungal biology, biodiversity, and conservation concepts likely to appear on the final exam.

Heterotrophic Bacteria

Bacteria that obtain carbon and energy by consuming organic compounds produced by other organisms.

Decomposer

An organism (often a heterotrophic bacterium or fungus) that breaks down dead organic material, recycling nutrients back into ecosystems.

Gram-Positive Bacteria

Bacteria with a thick peptidoglycan cell wall that retains crystal‐violet stain, appearing purple; often more sensitive to antibiotics like penicillin.

Gram-Negative Bacteria

Bacteria with a thin peptidoglycan layer and an outer membrane containing lipopolysaccharide; do not retain crystal-violet stain, appearing pink and often more antibiotic-resistant.

Horizontal Gene Transfer (HGT)

Movement of genes between organisms other than by vertical transmission (parent to offspring).

Transformation

HGT mechanism in which bacteria take up free DNA from their surroundings.

Transduction

HGT mechanism where bacteriophages transfer DNA from one bacterium to another.

Conjugation

HGT mechanism involving direct cell-to-cell contact and DNA transfer via a pilus.

Obligate Aerobe

Organism that requires O₂ for cellular respiration and cannot grow without it.

Obligate Anaerobe

Organism that is poisoned by O₂ and lives by fermentation or anaerobic respiration.

Facultative Anaerobe

Organism that can make ATP by aerobic respiration when O₂ is present but switches to fermentation or anaerobic respiration when O₂ is absent.

Biofilm

A structured community of microorganisms encased in extracellular polymeric substances and attached to a surface.

Taxis

Directed movement of an organism toward or away from a stimulus (e.g., chemotaxis toward nutrients).

Endospore

Dormant, highly resistant bacterial cell formed under stress, capable of surviving extreme conditions.

Extremophile

Microbe that thrives in physically or chemically extreme environments (e.g., high heat, salinity, acidity).

Virulence Factor

Any molecule or structure that enhances a pathogen’s ability to cause disease (e.g., toxins, adhesion proteins, capsules).

Heterotrophic Protist

Protist that feeds on organic matter; includes disease agents like Plasmodium (malaria) and Giardia (giardiasis).

Mushroom

The macroscopic, spore-producing fruiting body of many basidiomycete fungi.

Mold

Multicellular filamentous fungus that grows as a network of hyphae on substrates.

Yeast

Unicellular fungus that reproduces by budding or fission.

Hypha (plural: Hyphae)

A filamentous cell of a fungus; the basic structural unit of mycelium.

Mycelium

Interwoven mass of fungal hyphae that forms the vegetative body of a fungus.

Septate Hyphae

Fungal hyphae divided by cross-walls (septa) into individual, connected cells.

Aseptate (Coenocytic) Hyphae

Fungal hyphae lacking septa, forming a continuous multinucleate cytoplasm.

Ergotism

Poisoning caused by ingestion of alkaloids produced by the fungus Claviceps purpurea on grains; symptoms include convulsions and hallucinations.

Mycorrhizae

Mutualistic association between fungal hyphae and plant roots that enhances nutrient uptake.

Ringworm

Cutaneous fungal infection (dermatophytosis) causing circular lesions on skin.

Genetic Diversity

Variation in genes within a species or population.

Species Diversity

Number and relative abundance of species in an ecosystem or on Earth.

Ecosystem Diversity

Variety of ecosystems within a region or the planet.

Ecosystem Services

Benefits humans gain from ecosystems, including provisioning, regulating, cultural, and supporting services.

Provisioning Services

Ecosystem products such as food, water, timber, and medicines.

Regulating Services

Ecosystem processes that regulate climate, floods, disease, and water quality.

Habitat Loss

Destruction or fragmentation of natural habitats; the leading cause (#1) of species declines and extinctions.

Invasive Species

Non-native species that spread rapidly and outcompete native species, threatening biodiversity.

Overexploitation

Unsustainable harvesting of wild organisms leading to population declines.

Climate Change

Long-term alteration of temperature and typical weather patterns, largely driven by human greenhouse gas emissions.

Pollution

Introduction of harmful substances or energy into the environment, impacting organisms and ecosystems.

Minimum Viable Population (MVP)

Smallest population size at which a species can sustain its numbers and survive long-term.

Endangered Species

Species at risk of extinction throughout all or a significant portion of its range.

Threatened Species

Species likely to become endangered in the near future.

Extinction Vortex

Downward population spiral where inbreeding and genetic drift reduce genetic diversity, lowering fitness and leading to further declines.

Critical Load

Maximum amount of a nutrient (e.g., nitrogen, phosphorus) that an ecosystem can absorb without damaging effects.

Greenhouse Effect

Warming of Earth’s surface due to atmospheric gases (CO₂, CH₄, etc.) trapping outgoing infrared radiation.

Bioaccumulation

Build-up of a substance (often a persistent toxin like mercury or DDT) in an organism over time.

Biomagnification

Increase in concentration of a substance at successive trophic levels of a food chain.

Conservation Biology

Scientific study aimed at understanding and protecting Earth’s biodiversity through habitat preservation, species management, and restoration.