Cells: The Living Units

A set of vocabulary flashcards based on the key concepts and terms related to cell structure and function.

Cell Theory

The fundamental concept that cells are structural and functional units of life and arise only from preexisting cells.

Plasma Membrane

The flexible outer boundary of a cell, controlling the movement of substances in and out.

Fluid Mosaic Model

Describes the structure of the plasma membrane as a dynamic and fluid combination of phospholipids, cholesterol, and proteins.

Phospholipids

Molecules that form the lipid bilayer of the cell membrane, consisting of a hydrophilic phosphate head and hydrophobic fatty acid tails.

Membrane Proteins

Components of the plasma membrane that perform specialized functions such as transport, receptors, attachments, and enzymatic activity.

Passive Processes

Movements across the plasma membrane that do not require energy, such as diffusion and osmosis.

Active Processes

Movements across the plasma membrane that require energy (ATP), including active transport and vesicular transport.

Osmosis

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

Isotonic Solutions

Solutions that have the same osmotic pressure and solute concentration, preventing net movement of water into or out of cells.

Sodium-Potassium ATPase (Pump)

An active transport mechanism that moves sodium out of and potassium into the cell, using ATP.

Endocytosis

The process of taking substances into a cell through vesicle formation, which includes types like phagocytosis, pinocytosis, and receptor-mediated endocytosis.

Exocytosis

The process of removing substances from a cell by packaging them into vesicles that fuse with the plasma membrane.