Cell Membranes - BIOS 101

These flashcards cover terminology and key concepts related to cell membranes from the BIOS 101 lecture notes.

Fluid Mosaic Model

Describes the cell membrane as a dynamic, two-dimensional fluid where proteins and lipids move and interact, creating a mosaic pattern for various cellular functions.

Selective Permeability

The ability of cell membranes to control the movement of molecules and ions in and out of the cell, maintaining homeostasis.

Passive Transport

The movement of molecules across the cell membrane without the use of cellular energy, typically along a concentration gradient.

Active Transport

A cellular process that moves molecules across a membrane against their concentration gradient, requiring energy, typically in the form of ATP.

Endocytosis

The process by which a cell engulfs extracellular material through the folding of the cell membrane, forming a vesicle.

Phagocytosis

A type of endocytosis that involves the engulfment of large particles, such as bacteria or cellular debris.

Pinocytosis

A type of endocytosis that involves the uptake of fluids and dissolved solutes.

Receptor-mediated endocytosis

Selective uptake of specific molecules that bind to receptors on the cell surface.

Channel Proteins

Integral membrane proteins that form pores or channels in the membrane, allowing specific molecules to pass through.

Carrier Proteins

Integrity proteins that bind to specific molecules and change shape to transport them across the membrane, used in both passive and active transport.

Sodium-Potassium Pump

An example of active transport that moves sodium ions out of the cell and potassium ions into the cell, crucial for maintaining cell volume and membrane potential.

Cotransport (Secondary Active Transport)

Transport where the movement of one substance down its gradient is coupled to the movement of another substance against its gradient.

Glycoproteins

Proteins with carbohydrate chains attached that serve as recognition markers and play roles in cell signaling and adhesion.

Glycolipids

Lipids with carbohydrate chains attached that are involved in cell recognition and membrane stability.

Homeostasis

The maintenance of a stable internal environment within a cell.

Concentration Gradient

The gradual change in the concentration of solutes in a solution as a function of distance through a solution.

Transmembrane Proteins

Integral proteins that span the entire membrane, often functioning as channels or receptors.

Peripheral Proteins

Membrane proteins that are not embedded in the lipid bilayer, easily dissociated from the membrane.

Membrane Potential

The electrical potential difference across a cell's plasma membrane, crucial for cellular signaling.

Osmosis

The movement of water across a semipermeable membrane from an area of higher water concentration to an area of lower concentration.

Tonicity

Describes the ability of a solution to alter the water balance of cells through osmosis.

Equilibrium

A state in which opposing forces or influences are balanced.

Exocytosis

The process where vesicles fuse with the plasma membrane to release their contents into the extracellular space.