Cellular Transport and Plant Homeostasis

Practice vocabulary flashcards covering passive and active cellular transport, tonicity, homeostatic feedback loops, and plant leaf anatomy.

Concentration Gradient

The condition of having different amounts of molecules on either side of a membrane, causing molecules to move naturally toward the area where there are fewer molecules.

Diffusion

The passive transport of molecules from an area of high concentration to an area of low concentration without the use of ATP, continuing until dynamic equilibrium is reached.

Dynamic Equilibrium

The state reached through diffusion when all molecules are evenly spaced throughout an area and continue moving.

Passive Transport

Cellular transport that moves substances from high to low concentration without requiring cellular energy (ATP), such as diffusion, osmosis, and facilitated diffusion.

Osmosis

The diffusion of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration without requiring energy.

Facilitated Diffusion

A type of passive transport where particles that are too large to cross the membrane directly are carried through by proteins from high to low concentration without requiring energy.

Active Transport

The movement of substances against the concentration gradient from an area of low concentration to high concentration, requiring energy in the form of ATP.

Endocytosis

An active transport process requiring energy where the cell membrane folds inward, fuses together, and pinches off to form a vesicle, bringing large substances into the cell.

Phagocytosis

A form of endocytosis often referred to as 'cell eating' that involves bringing solid materials or food particles into the cell.

Pinocytosis

A form of endocytosis often referred to as 'cell drinking' that involves bringing liquid materials into the cell.

Exocytosis

An active transport process requiring energy where vesicles carry waste or undigested materials to the cell membrane, fuse with it, and secrete the contents out of the cell.

Hypertonic

A solution that has a higher concentration of solute and a lower concentration of free water compared to another solution.

Hypotonic

A solution that has a lower concentration of solute and a higher concentration of free water compared to another solution.

Isotonic

A state where the solute and free water concentrations are equal inside and outside the cell, resulting in no net movement of water.

Plasmolysis

The process in which the plasma membrane of a plant cell shrinks away from inside the cell wall due to water loss in a hypertonic environment.

Homeostasis

The continuous process by which an organism maintains a stable internal environment despite disruptions caused by internal and external environmental fluctuations.

Negative Feedback Loop

The most common type of feedback loop that limits chaos and prevents sudden bodily changes by correcting the set point and causing the opposite of the disruption to occur.

Positive Feedback Loop

An infrequent, short-duration regulatory loop that increases or intensifies an action in the body, producing more instability until an event (such as blood clotting or childbirth) is finished.

Nervous System

The body system responsible for rapid-response regulation to help maintain homeostasis.

Endocrine System

The body system responsible for slower-response regulation to help maintain homeostasis.

Baroreceptors

Sensory receptors located in the walls of arteries that stretch under blood pressure and signal the brain to adjust heart rate in a negative feedback mechanism.

Cuticle

The waxy upper layer of a plant leaf that provides protection.

Upper Epidermis

The protective leaf tissue layer beneath the cuticle that contains no chloroplasts.

Palisades Layer

A tightly packed layer of cells in a leaf where most photosynthesis takes place.

Spongy Mesophyll

A loosely packed leaf tissue layer with air spaces, very little photosynthesis, and vascular tissues including xylem and phloem.

Xylem

The vascular tube in a plant that functions as a water tube.

Phloem

The vascular tube in a plant that functions as a food tube.

Stomata

Small holes located mostly in the lower epidermis of a leaf that facilitate gas exchange and water loss.

Guard Cells

Specialized cells located in the lower epidermis that open and close the stomata to regulate plant homeostasis.

Transpiration

The process by which water exits leaf stomata as water vapor, helping regulate temperature, water, and molecular movement in plants.