Cell Membrane Structure and Function

A comprehensive vocabulary review of cell membrane architecture, lipid properties, transport proteins, and the fluid-mosaic model based on the lecture notes.

Cell membrane

A cellular boundary that separates the cell from its surroundings, controls what substances can enter and leave, provides protection, and assists in communicating with the outside environment.

Lipid bilayer

A fundamental membrane structure consisting of two layers of phospholipids, where water-loving heads face the water on the inside and outside of the cell and water-fearing tails point toward each other in the center.

Saturated fatty acids

Fatty acids that do not contain double bonds and have straighter tails that fit closely and pack more tightly together, making the cell membrane less fluid and more rigid.

Unsaturated fatty acids

Fatty acids that contain one or more double bonds creating kinks in the tails, preventing molecules from packing tightly and making the membrane more fluid.

Trans fatty acids

Fatty acids that contain a double bond but have a straighter shaped tail than cis unsaturated fatty acids, allowing them to pack closely together.

Phospholipids

Lipids composed of fatty acid tails, a glycerol backbone, and a phosphate-containing head, which naturally arrange into a bilayer due to having hydrophilic and hydrophobic parts.

Triglycerides

Lipids containing three fatty acid tails that are primarily used to store energy.

Waxes

Lipids made from fatty acids and alcohols used for protection and waterproofing, which are completely water repellent and unable to form a protective bilayer.

Glycerol

A molecule that can serve as the structural backbone connecting fatty acids together in lipids.

Phosphatidic acids

Molecules that can aid the structure of phospholipids when constructing a cell membrane.

Integral proteins

Membrane proteins located within the lipid bilayer that possess the potential to pass through the membrane.

Peripheral proteins

Membrane proteins that are attached to the hydrophilic heads of the lipid bilayer.

Receptor proteins

Proteins that recognize specific chemical signals and trigger an internal cellular response when a signal attaches to them.

Passive transport

A transport process that moves substances from an area of higher concentration to an area of lower concentration without requiring energy.

Active transport

A transport process that requires energy to move substances from an area of lower concentration to an area of higher concentration.

Channel proteins

Transport proteins that form openings allowing specific substances to pass through the membrane.

Carrier proteins

Transport proteins that bind to specific substances and change shape to move them across the cell membrane.

Gated channels

Membrane channels that open and close in response to specific signals, such as chemicals, changes in voltage, or other changes around the cell.

Fluid-mosaic model

A model describing the cell membrane as a flexible structure where lipids and proteins can move, containing an arrangement of many different types of molecules.

Glycoproteins

Membrane proteins with attached surface carbohydrates that act like identification tags to aid in cell recognition and communication.

Glycolipids

Membrane lipids with attached carbohydrate groups on their surfaces that serve as identification tags to assist cells in recognizing and communicating with each other.