BIOL 1107K Cell Membrane Vocabulary

Vocabulary flashcards covering cell membrane composition, factors affecting fluidity, cholesterol buffering, and membrane protein types and functions based on lecture notes.

Cell membrane

A physical barrier that separates internal components (cytoplasm) from the extracellular space, controls the movement of ions, nutrients, and waste, and provides structural support to maintain cell shape.

Membrane fluidity

The flexibility and movement characteristic of cell membranes, which is influenced by phospholipid structure, temperature, and cholesterol.

Unsaturated phospholipids

Phospholipids in the cell membrane that are loosely packed due to kinks in their hydrocarbon tails, increasing membrane fluidity.

Saturated phospholipids

Phospholipids in the cell membrane with straight hydrocarbon tails that allow them to be tightly packed together.

Van der Waals interactions

Weak non-covalent interactions between phospholipid tails that help prevent membrane phospholipids from completely separating at elevated temperatures.

Cholesterol

An amphipathic lipid component embedded in the cell membrane whose hydrophobic region forms van der Waals interactions with phospholipid tails to buffer membrane fluidity.

Cholesterol buffering (low temperature)

The mechanism by which embedded cholesterol forces phospholipids farther apart at low temperatures to prevent tight packing and increase membrane fluidity.

Cholesterol buffering (high temperature)

The mechanism by which embedded cholesterol attracts phospholipid molecules at high temperatures to restrict movement and decrease membrane fluidity.

Fluid Mosaic Model

A structural description of the plasma membrane as a fluid structure where components can migrate, composed of a mosaic of phospholipids, cholesterol, and proteins.

Integral proteins

Amphipathic membrane proteins permanently imbedded in the plasma membrane that span its width, having hydrophilic regions interacting with aqueous spaces and hydrophobic regions interacting with lipid tails.

Peripheral proteins

Proteins attached to the exterior or interior surface of the plasma membrane rather than spanning its hydrophobic interior.

Membrane protein functions

The distinct roles executed by cell membrane proteins, including transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, and attachment.