Cell Membrane Transport and Function

These flashcards cover key vocabulary related to cell membranes, transport mechanisms, and the principles of thermodynamics relevant to biological systems.

Fluid Mosaic Model

A model that describes the structure of cell membranes as a mosaic of components, including phospholipids, cholesterol, and proteins.

Phospholipids

Molecules that comprise the cell membrane, featuring hydrophilic heads and hydrophobic tails, allowing for dynamic movement.

Compartmentalization

The process in which different cellular processes occur within distinct compartments of a cell, enhancing efficiency.

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration, occurring without energy expenditure.

Facilitated Diffusion

A type of passive transport that moves molecules across the plasma membrane via transport proteins or channels.

Active Transport

The process of moving ions or molecules against their concentration gradient, requiring energy, usually in the form of ATP.

Thermodynamics

The branch of physics that deals with the relationships and conversions between heat and other forms of energy, essential in cellular processes.

Entropy

A measure of disorder or randomness in a system; according to the second law of thermodynamics, entropy of an isolated system always increases.

Osmosis

The diffusion of water across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.

Isotonic Solution

A solution where the concentration of solutes outside the cell is equal to the concentration inside the cell, resulting in no net movement of water.

Hypertonic Solution

A solution with a higher concentration of solutes compared to the inside of the cell, causing the cell to lose water and shrink.

Hypotonic Solution

A solution with a lower concentration of solutes compared to the inside of the cell, leading to water influx and potential cell swelling.

Membrane Proteins

Proteins that are embedded in the cell membrane, aiding in transport, communication, and catalysis within the cell.

Channel Proteins

Membrane proteins that facilitate the transport of ions and small molecules by forming pores in the membrane.

Transporter Proteins

Proteins that help move molecules across the membrane through facilitated diffusion or active transport.

GLUT-1

A glucose transporter protein that facilitates the diffusion of glucose across the plasma membrane.

Sodium-Potassium Pump

A transport protein that uses ATP to move sodium ions out of the cell and potassium ions into the cell, against their concentration gradients.

Electrochemical Gradient

The combined difference in concentration and charge across a membrane that influences the movement of ions.

Amphipathic

Molecules, such as phospholipids, that have both hydrophilic and hydrophobic properties, crucial for membrane structure.