Study Guide: Chapter 5 - Membranes

These flashcards cover essential vocabulary and concepts related to cell membranes, their structure, transport mechanisms, and functions as outlined in Chapter 5.

Fluid Mosaic Model

A model describing the structure of cell membranes where proteins float in or on a fluid lipid bilayer.

Phospholipid Bilayer

A double layer of phospholipids that makes up the cell membrane, with hydrophilic heads facing outward and hydrophobic tails facing inward.

Integral Proteins

Proteins that are embedded in the cell membrane and can span the entire lipid bilayer.

Peripheral Proteins

Proteins that are attached to the exterior or interior surfaces of the membrane but do not penetrate the lipid bilayer.

Tonicity

The measure of the concentration of solutes in a solution that affects the movement of water across a membrane.

Osmosis

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

Hypertonic

A solution with a higher concentration of solutes compared to another solution.

Hypotonic

A solution with a lower concentration of solutes compared to another solution.

Isotonic

A solution with equal concentrations of solutes compared to another solution.

Aquaporins

Channel proteins that facilitate the transport of water across cell membranes.

Active Transport

The process that requires energy (ATP) to move substances against their concentration gradient.

Sodium-Potassium Pump

An example of an active transport mechanism that moves sodium out of the cell and potassium into the cell.

Endocytosis

The process by which cells take in materials from the outside by engulfing them in a membrane.

Phagocytosis

A type of endocytosis where cells ingest solid material.

Pinocytosis

A type of endocytosis where cells ingest liquid material.

Receptor-Mediated Endocytosis

A process where cells take in specific molecules based on their binding to receptors.