Lecture 5 pt 1 Cellular Transport, Junctions, and Energy Principles

Vocabulary practice flashcards covering membrane transport mechanisms, bulk transport, cell junctions, and thermodynamic principles based on the lecture transcript.

Osmosis

The diffusion of water across a differentially permeable membrane from a region of higher water concentration to a region of lower water concentration.

Osmotic Pressure

The pressure that develops in a system due to osmosis; greater osmotic pressure increases the rate of water diffusion.

Aquaporin

A specific channel protein in the plasma membrane that facilitates the entry of water into the cell.

Carrier Protein

A membrane protein that specifically binds molecules or ions and undergoes a conformational change in shape to transport them across the membrane.

Facilitated Transport

The passive movement of molecules (such as glucose and amino acids) down their concentration gradient via carrier or channel proteins without requiring ATP.

Active Transport

The movement of molecules against their concentration gradient across a cell membrane, requiring carrier proteins and energy in the form of ATP.

Sodium-Potassium Pump

An active transport carrier protein critical in nerve and muscle cells that pumps sodium out of the cell and moves potassium into the cell using a phosphate group donated by ATP.

Exocytosis

A process of bulk transport where a vesicle (often from the Golgi apparatus) fuses with the plasma membrane to secrete macromolecules out of the cell.

Endocytosis

A process of bulk transport where cells take in macromolecules by invaginating a portion of the plasma membrane to form a vesicle inside the cell.

Phagocytosis

A type of endocytosis that ingests large particulate matter, such as food particles, viruses, and whole cells; common in amoebas and macrophages.

Pinocytosis

A form of endocytosis that brings liquid and small dissolved particles into the cell; common in blood cells and plant root cells.

Receptor-Mediated Endocytosis

A highly specific form of pinocytosis involving plasma membrane pits coated with receptor proteins designed to bind specific target molecules.

Extracellular Matrix (ECM)

A meshwork of proteins and polysaccharides found outside animal cells that provides structural support and helps maintain cell shape.

Adhesive Junction

A type of cell junction in animal tissues where proteins connect the cytoskeletal filaments of adjacent cells.

Tight Junction

A cell junction where proteins connect the plasma membranes of adjacent cells to form an impermeable barrier.

Gap Junction

A specialized cell junction in animal cells that allows direct communication between adjacent cells.

Plasmodesmata

Narrow channels penetrating plant cell walls containing cytoplasm strands that allow the exchange of water and small molecules between adjacent plant cells.

Pectin

A polysaccharide substance abundant in the middle lamella of plant cell walls that allows the cell wall to stretch and holds adjacent plant cells together.

Potential Energy

Stored energy, such as chemical energy held within the chemical bonds of carbohydrate molecules.

Kinetic Energy

The energy of motion, such as mechanical energy expended during physical movement.

First Law of Thermodynamics

The principle stating that energy can neither be created nor destroyed, but can only be changed or converted from one form to another.

Second Law of Thermodynamics

The principle stating that energy transformation processes cannot occur without the loss of some usable energy, which is released as unusable heat into the environment.