BIO111 Study Guide Chapter 8 – Membrane Structure and Function

These flashcards cover key concepts and vocabulary related to membrane structure and function, including types of transport, membrane properties, and specific processes.

Permeability

State or quality that allows liquids or gasses to pass through it.

Dynamic equilibrium

Molecules are still moving but molecules are evenly distributed; diffusion stops.

Concentration gradient

Areas of higher and lower concentration; substances move from high to low concentration.

Transport protein

Proteins that assist in the movement of substances across a cell membrane.

Fluid-mosaic model

A model that describes the structure of cell membranes, characterized by a phospholipid bilayer with embedded proteins.

Glycoproteins

Proteins with carbohydrate chains attached that help in cell recognition and signaling.

Glycolipids

Lipids with carbohydrate chains that assist in immune recognition processes.

Selectively permeable

Property of cell membranes that allows some substances to cross more easily than others.

Diffusion

Passive transport process where molecules move from an area of higher concentration to an area of lower concentration.

Simple diffusion

The movement of small, nonpolar molecules (like oxygen) directly through the membrane without assistance.

Facilitated diffusion

The process by which larger or charged molecules cross the membrane through protein channels.

Active transport

The movement of molecules against their concentration gradient, requiring energy input.

Passive transport

Movement of substances across cell membranes without the use of energy.

Channel proteins

Transmembrane proteins that form openings to allow specific substances to pass through membranes.

Carrier proteins

Proteins that bind substances on one side of the membrane, change shape, and release them on the other side.

Sodium-potassium pump

A membrane protein that moves sodium ions out of cells and potassium ions into cells against their concentration gradients.

Osmosis

The diffusion of water across a selectively permeable membrane, passive and does not require energy.

Tonicity

How a solution affects water movement into or out of a cell.

Aquaporin

Channel proteins specifically allowing water to pass through cell membranes.

Hypertonic solution

A solution that has a higher concentration of solute compared to the inside of a cell.

Hypotonic solution

A solution that has a lower concentration of solute compared to the inside of a cell.

Isotonic solution

A solution that has an equal concentration of solute compared to the inside of a cell.

Endocytosis

Process by which cells take in materials by engulfing them in a vesicle.

Phagocytosis

Type of endocytosis in which large particles are engulfed by cells.

Pinocytosis

Type of endocytosis that engulfs small particles and fluids.

Receptor-mediated endocytosis

Endocytosis that involves specific recognition and binding of substances to receptors before engulfing.

Exocytosis

Process by which cells expel materials in vesicles that fuse with the plasma membrane.