Biology Now: Microbes, Plants, Fungi, and Protists Flashcards

Vocabulary flashcards covering Chapters 15 and 16 of Biology Now 4th Edition with Physiology, focusing on bacteria, archaea, protists, plants, and fungi.

Human Microbiome

The complete collection of microbes that live in and on human cells and bodies.

Stromatolites

Rock structures with distinct physical patterns indicative of ancient bacterial activity, with the oldest suggesting bacteria existed 3.7 billion years ago.

Prokaryotes

Single-celled organisms in the domains Bacteria and Archaea that possess a single loop of DNA and lack membrane-enclosed organelles.

Citizen Science

Projects in which members of the public participate in scientific research by contributing, collecting, or analyzing data in cooperation with professional scientists.

Bacillus

A rod-shaped bacterial or archaeal cell.

Coccus

A sphere-shaped bacterial or archaeal cell.

Spirochete

A corkscrew-shaped bacterial or archaeal cell.

Spirillum

A spiral-shaped bacterial or archaeal cell.

Vibrio

A comma-shaped bacterial or archaeal cell.

Capsule

A protective outer layer surrounding the cell wall of some prokaryotes that helps disease-causing bacteria evade the host immune system.

Pili

Short, hairlike projections on many prokaryotic cells used to link cells together or attach to surrounding surfaces.

Flagellum

A long, whiplike cellular structure used by certain prokaryotes to propel themselves through liquid environments.

Thermophiles

Organisms, often belonging to domain Archaea, known as 'heat lovers' because they thrive in extreme high-temperature environments.

Halophiles

Organisms, often belonging to domain Archaea, known as 'salt lovers' because they thrive in extremely salty environments.

Quorum Sensing

A cell-to-cell communication system that enables microbes to sense population density and coordinate group behavior.

Biofilms

Tough aggregate microbial communities formed by bacteria that coordinate their activities using quorum sensing.

Binary Fission

A method of asexual reproduction in prokaryotes in which parent cell DNA is duplicated and divided equally into two daughter cells.

Horizontal Gene Transfer

The process by which microbes capture foreign DNA fragments from their surroundings or other organisms and integrate them into their own genomes.

Bacterial Conjugation

A mechanism of genetic exchange in which one bacterium directly trades DNA with another bacterium.

Sporulation

The process by which certain bacteria form thick-walled, highly resilient structures called spores to survive boiling, freezing, and antibiotics.

Aerobes

Organisms that require oxygen to perform cellular metabolic functions and survive.

Anaerobes

Organisms that do not require oxygen for metabolic processes and can survive in oxygen-free environments.

Methanogens

Anaerobic prokaryotes that feed on hydrogen and produce methane gas as a byproduct.

Chemoheterotrophs

Heterotrophic organisms that consume organic molecules to obtain both energy and carbon.

Photoheterotrophs

Heterotrophic organisms that obtain carbon from organic compounds while deriving their energy from sunlight.

Chemoautotrophs

Autotrophic organisms that obtain carbon from carbon dioxide ($CO_2$) and energy from inorganic chemicals in their environment.

Photoautotrophs

Autotrophic producers that absorb light energy and fix carbon dioxide ($CO_2$) to produce organic compounds via photosynthesis.

Cyanobacteria

A group of aquatic photoautotrophic bacteria that evolved oxygenic photosynthesis, significantly increasing atmospheric oxygen gas levels around 2.1 billion years ago.

Nitrogen Fixation

The metabolic process in which specialized bacteria convert atmospheric nitrogen gas ($N_2$) into ammonia ($NH_3$), making nitrogen available to plants.

Decomposers

Consumer organisms that break down organic waste and dead organisms, releasing essential nutrient elements back into the ecosystem through nutrient cycling.

Dysbiosis

A state of microbial imbalance in or on the human body that can lead to disease or adverse health conditions.

Domain Eukarya

The domain of life comprising organisms with eukaryotic cells featuring a true double-membrane-bound nucleus and specialized membrane-bound organelles.

Protists

An artificial category of eukaryotes defined by exclusion, encompassing predominantly single-celled organisms that are not classified as plants, animals, or fungi.

Protozoans

A traditional category of nonphotosynthetic, motile protists.

Algae

Photosynthetic protists that may or may not be motile.

Pseudopodia

Temporary cellular extensions ('false feet') used by certain protists for movement and crawling.

Mixotrophs

Nutritional opportunist organisms that can utilize energy and carbon from various autotrophic and heterotrophic sources.

Plasmodium

A pathogenic protist transmitted to humans by mosquitoes that causes malaria.

Toxoplasma gondii

A pathogenic protist spread through undercooked food or cat feces, causing mild symptoms in adults but severe damage to developing fetuses.

Zygote

A single diploid cell resulting from the fusion of male and female gametes (sperm and egg).

Embryo

A multicellular structure that develops from the repeated mitotic division of a zygote.

Bryophytes

Simple nonvascular land plants, including liverworts and mosses, that grow close to the ground and absorb water through wicking action.

Vascular System

A specialized plant network of tubelike structures designed for the efficient transport of fluids throughout the plant body.

Lignin

An exceptionally strong biopolymer that cross-links cellulose fibers within plant cell walls to provide rigid structural support, enabling plants to grow tall.

Cellulose

A structural polysaccharide that provides mechanical strength to cell walls in green algae and terrestrial plants.

Pollen

A microscopic structure containing plant sperm cells that can be transported through the air, eliminating the requirement of free water for fertilization.

Seed

A plant structure comprising a protective outer coat, an embryo, and an internal nutrient reserve for initial growth before photosynthesis begins.

Gymnosperms

A lineage of seed plants, including cycads and conifers, that were the first group to evolve pollen and non-flowering seeds.

Angiosperms

Flowering plants, which constitute the most dominant and ecologically diverse lineage of terrestrial plants.

Flowers

Reproductive structures in angiosperms that facilitate sexual reproduction by attracting animal pollinators and uniting sperm and egg gametes.

Ovules

Egg-bearing structures inside the ovary of angiosperms that mature into seeds following fertilization.

CITES

The Convention on International Trade in Endangered Species, an international accord among over 175 countries regulating wildlife and plant trade to prevent extinction.

Fungi

Eukaryotic absorptive heterotrophs that release digestive enzymes externally into their environment and absorb the resulting breakdown products.

Zygomycetes

A major fungal lineage comprising various molds.

Ascomycetes

A diverse lineage of fungi, informally known as sac fungi, which includes yeasts and truffles.

Basidiomycetes

A fungal lineage informally designated as club fungi, containing typical mushroom-forming species.

Hyphae

Fine, transparent, branching cellular threads that form the primary nutrient-absorbing structures of a fungus.

Mycelium

The complete interconnected network of hyphae that constitutes the vegetative body of a fungus.

Spore

A resilient reproductive cell capable of persisting in a dormant state through unfavorable conditions before germinating into a new organism.

Mycorrhizal Fungi

Mutualistic fungi that associate with plant roots, supplying enhanced water and mineral uptake in exchange for photosynthetic carbohydrates.

Lichen

A mutualistic symbiotic partnership between a fungus and a photosynthetic organism, such as a green alga or cyanobacterium.