Plant and Animal Structure and Function

Comprehensive vocabulary flashcards covering plant and animal anatomy, tissue types, nutritional strategies, photosynthesis, and digestive systems.

Shoot System

The organ system of a plant comprising vegetative (non-reproductive) structures like stems and leaves, as well as reproductive structures including flowers and fruits.

Root System

The predominantly underground plant organ system that anchors the plant and absorbs water and inorganic minerals from the soil.

Dermal Tissue

The outer protective covering of a plant; the epidermis mediates gas exchange on aerial organs (stems and leaves) and facilitates water and ion uptake on roots.

Xylem

Vascular tissue comprised of non-living outer cells without end walls that carries water and inorganic minerals unidirectionally upwards from the roots to the stems and leaves.

Phloem

Vascular tissue made of living cells connected by perforated end walls (sieve plates) that transports organic molecules and dissolved sugars bidirectionally between leaves and other plant parts.

Vascular Bundles

Distinct vertical strands of xylem and phloem running the length of the stem, arranged in an organized outer ring in dicot stems and scattered throughout monocot stems.

Nodes

Specific points of attachment along a plant stem where leaves, aerial roots, and flowers emerge.

Internodes

The stem segments or intervals situated between two consecutive nodes.

Petiole

The structural stalk that attaches the leaf blade (lamina) to the plant stem.

Axillary Bud

A bud situated in the axil between the base of a leaf and the stem that can give rise to a branch or flower.

Apical Meristem

A zone of actively dividing undifferentiated cells located at the apex or growing tip of shoots and roots that drives primary growth.

Taproot System

A root system featuring a single prominent primary root that grows deep downward into the substrate with smaller lateral branches.

Fibrous Root System

A root architecture consisting of a dense network of numerous thin, similarly sized roots spreading out beneath the soil surface.

Root Hairs

Tubular, hair-like extensions of root epidermal cells that substantially expand the root surface area to optimize water and nutrient uptake.

Trichomes

Specialized hair-like outgrowths originating from epidermal cells on the aerial surfaces of plants.

Stomata

Microscopic epidermal apertures (singular: stoma) flanked by two guard cells that regulate uptake of $\text{CO}_2$ and the transpirational loss of water vapor and $\text{O}_2$.

Lamina

The broad, flattened photosynthetic portion of a leaf, commonly referred to as the leaf blade.

Sessile Leaf

A leaf that attaches directly to the plant stem without an intervening petiole.

Dichotomous Venation

A leaf venation pattern seen in plants like Ginkgo biloba where veins branch repeatedly into two roughly equal halves.

Palisade Mesophyll

The upper photosynthetic ground tissue layer in leaves composed of vertically elongated, tightly packed columnar cells containing abundant chloroplasts.

Spongy Mesophyll

The lower ground tissue layer of leaves composed of loosely organized, irregularly shaped cells interspersed with large air spaces that facilitate gas exchange.

Cuticle

A waxy hydrophobic layer coating the external surfaces of terrestrial plant epidermis that prevents desiccation.

Thylakoid Membrane

The internal disc-like membrane compartments within chloroplasts that contain photosynthetic pigments and carry out the light-dependent reactions.

Stroma

The aqueous fluid-filled matrix surrounding grana within a chloroplast where the light-independent Calvin cycle occurs.

Turgor Pressure

The hydrostatic pressure exerted by cell fluid against the rigid plant cell wall when placed in a hypotonic medium, keeping the plant upright.

Cellulose

The most abundant organic polymer on Earth, synthesized from glucose, that makes up over $30\%$ of plant matter and provides structural support to plant cell walls.

Humus

The organic fraction of soil consisting of living and dead microorganisms, along with decaying plant and animal residues.

Loam

Fertile soil containing a balanced mixture of sand, silt, and clay particles without a single dominant particle size.

Soil Composition

The volumetric profile of typical soil, consisting of approximately $40\text{ to }45\%$ inorganic mineral matter, $5\%$ organic matter, and $50\%$ water and air combined.

Water Table

The boundary depth below ground where porous rock and soil are completely saturated with groundwater.

Biological Nitrogen Fixation

The enzymatic conversion of atmospheric nitrogen ($\text{N}_2$) into ammonia ($\text{NH}_3$), performed exclusively by prokaryotes such as soil bacteria and cyanobacteria.

Mycorrhizae

Mutualistic symbiotic associations between fungi and plant roots where fungi enhance water and nutrient uptake in exchange for up to $20\%$ of the plant's photosynthetically derived carbohydrates.

Holoparasite

A completely parasitic plant (such as dodder) that lacks chlorophyll, cannot synthesize its own food, and directly invades a host's vascular tissues to extract nutrients.

Saprophyte

A plant lacking chlorophyll that derives nutrients from non-living organic matter by deploying enzymes, frequently relying on symbiotic fungi for digestion.

Epiphyte

A plant that grows physically anchored upon another plant for mechanical support without extracting nutritional resources from the host.

Radial Symmetry

A body organization pattern wherein body components are oriented around a central axis such that any 2-D longitudinal plane produces two mirror-image halves.

Bilateral Symmetry

A body plan possessing distinct left and right sides where only a single sagittal plane divides the animal into two mirror-image halves.

Basal Metabolic Rate (BMR)

The baseline rate of energy metabolism; smaller endothermic animals exhibit higher BMR per unit mass than larger ones to compensate for higher heat loss caused by higher surface area-to-volume ratios.

Epithelial Tissue

Animal tissue comprised of tightly packed cells that line internal cavities, external surfaces, and hollow tubes, classified by cell shape and layer count.

Connective Tissue

A primary animal tissue type consisting of cells such as fibroblasts embedded in an extracellular matrix containing collagen, reticular, or elastic fibers.

Skeletal Muscle

Striated, voluntarily controlled muscle tissue consisting of long, unbranched cells with multiple peripheral nuclei attached to bones.

Smooth Muscle

Non-striated, involuntary muscle tissue composed of spindle-shaped cells with a single centrally located nucleus found in visceral organ walls.

Cardiac Muscle

Striated, involuntarily controlled muscle tissue found exclusively in the heart, featuring branched fibers, single central nuclei, and intercalated discs.

Gastrovascular Cavity

An incomplete digestive tract with a single opening serving as both mouth and anus, found in simpler animals like planarians.

Alimentary Canal

A complete digestive system with two separate openings—a mouth for ingestion and an anus for egestion—enabling one-way digestive transit.

Ruminant Stomach

A specialized four-chambered stomach (comprising rumen, reticulum, omasum, and abomasum) adapted for microbial fermentation and regurgitation of tough plant matter.

Peristalsis

Rhythmic, coordinated waves of muscular contractions that propel food boluses down the esophagus and through the alimentary tract.

Chyme

The acidic, semi-fluid mixture of partially digested food, enzymes, water, and hydrochloric acid produced in the stomach and passed into the small intestine.

Villi

Finger-like mucosal folds lining the small intestine that increase luminal surface area to maximize nutrient absorption into capillaries and lacteals.

Bile

A digestive fluid synthesized by the liver and stored in the gallbladder that emulsifies dietary lipids into smaller droplets to enhance pancreatic lipase action.