BIO 201; CREIGHTON UNIVERSITY; UNIT 2 PLANT BIOLOGY

The net passive movement of molecules from an area of higher concentration to an area of lower concentration.

Diffusion of small, non-polar molecules (O2/CO2) or tiny polar molecules (water) directly across the phospholipid bilayer without the aid of a transport protein.

Passage of a substance through a barrier or membrane.

Passive movement of molecules (often polar molecules or ions) across a membrane with the help of a membrane transport protein (channel or carrier).

A transport protein that provides a hydrophilic pore or tunnel through the membrane, allowing specific ions or water to pass through very quickly down their concentration gradient.

A transport protein that binds to a specific molecule on one side of the membrane, changes its conformation, and then releases the molecule on the other side.

Active transport where the energy is derived directly from the hydrolysis of ATP (the Na+/K+ ATPase pump).

Active transport where the energy is stored in a pre-existing electrochemical gradient created by primary active transport.

A mathematical relationship stating that diffusion rate is proportional to surface area, concentration gradient, and membrane permeability, and inversely proportional to membrane thickness.

R ∝ (Area × Concentration Gradient) / Distance.

The combined force determining ion movement across a membrane—includes both the chemical concentration gradient and the electrical potential gradient.

The state where the electrical gradient exactly opposes the chemical gradient, resulting in no net ion movement.

The net passive movement of water across a semi-permeable membrane from lower solute concentration to higher solute concentration.

A measure of total solute particle concentration in a solution, expressed as osmoles per liter.

Having the same total solute concentration as another solution.

A solution with a lower osmolarity than another solution.

A solution with a higher osmolarity than another solution.

The potential energy of water relative to pure water; water moves from high to low water potential.

Ψtotal = Ψosmotic + Ψpressure + Ψmatrix.

The component of water potential due to dissolved solutes; always negative or zero.

The component of water potential caused by physical pressure on water; can be positive or negative.

The component of water potential due to water adhesion to solid surfaces like soil or cell walls.

French physiologist who proposed that internal conditions of the body must remain constant.

The fluid environment surrounding cells that must remain stable for survival.

All body fluid outside cells, including interstitial fluid and plasma.

The portion of ECF that directly bathes body cells.

The active process of maintaining a variable within a specific range.

The body’s tendency to maintain stable internal conditions.

Movement of a substance into a cell.

Movement of a substance out of a cell.

Mechanism where the system output reduces the original stimulus, maintaining stability.

Part of a feedback loop that processes information and sends commands to effectors.

Part of a feedback loop that carries out corrective actions to restore balance.

Rigid, protective structure outside the plasma membrane of plant, fungal, algal, and bacterial cells.

A glucose-based polysaccharide forming the main structural component of plant cell walls.

A complex polymer strengthening secondary cell walls, especially in vascular tissues.

Microscopic channels connecting plant cells for transport and communication.

Large, membrane-bound organelle for water storage and maintaining turgor pressure in plant cells.

Regions of actively dividing, undifferentiated plant cells responsible for growth.

Meristem tissue at root and shoot tips responsible for length growth.

Meristem tissue running parallel to stemsoots; includes vascular and cork cambium.

Ability of a plant cell to become any cell type and form a new plant.

Growth increasing the length of shoots and roots.

Growth increasing the girth of stems and roots.

Continuous plant growth with no predetermined size limit.

Simple tissues have one cell type; complex tissues have multiple.

Node—stem point where leaves or branches attach; internode—segment between nodes.

Protective cell layer covering the tip of the root meristem.

Tiny epidermal outgrowths that increase root surface area for absorption.

Above-ground roots providing structural support.

Specialized aerial roots growing upward for gas exchange.

Main plant axis, typically above ground, supporting leaves and flowers.

Horizontal stem growing along the soil surface.

Horizontal stem growing underground.

Enlarged underground storage stem.

Broad, flat part of a leaf.

Stalk attaching the leaf blade to the stem.

Short underground stem surrounded by storage leaves.

Thin, coiling structure for plant support and climbing.

Outermost protective plant covering.

Bulk of the plant body; includes cortex, pith, and mesophyll.

Transport tissue system forming veins and bundles.

Single outer layer of dermal tissue covering the plant.

Hair-like epidermal outgrowth.

Waxy, water-impermeable layer on epidermis.

Pore in epidermis regulating gas exchange, surrounded by guard cells.

Common plant cells, thin-walled, living, and totipotent.

Living cells with unevenly thickened walls for support.

Thick-walled, lignified, usually dead support cells.

Vascular tissue transporting water and minerals upward.

Vascular tissue transporting sugars throughout the plant.

Long, narrow xylem cell for water conduction via pits.

Short, wide xylem cell forming continuous tubes for water transport.

Main phloem cell conducting food; lacks nucleus.

Active phloem cell supporting sieve tube members.

Accumulated secondary xylem tissue.

Lateral meristem forming a ring in stems and roots.

Lateral meristem forming protective outer layers.

Visible wood rings marking yearly xylem growth.