Chapter 5: Membrane Structure Flashcards

Flashcards about membrane structure and fuctions.

Cell Membrane

The outer boundary of a cell that separates its internal environment from the external environment.

Major components of the cell membrane

The phospholipid bilayer, proteins, and carbohydrates.

Fluid-Mosaic Model

A model describing the cell membrane as a mosaic of lipids, proteins, and carbohydrates that are constantly moving.

Selective permeability

A property of the plasma membrane that allows some substances to cross more easily than others.

Amphipathic molecules

Molecules with both polar (hydrophilic) and nonpolar (hydrophobic) regions.

Integral proteins

Proteins that penetrate the hydrophobic interior of the lipid bilayer.

Transmembrane proteins

Integral proteins that span the entire membrane.

Lipid-anchored proteins

Proteins with an amino acid covalently attached to a lipid.

Peripheral proteins

Proteins loosely bound to the surface of the membrane.

Transport proteins

Membrane proteins involved in the movement of ions and molecules across the plasma membrane.

Enzymes

Membrane proteins that catalyze chemical reactions.

Receptor proteins

Membrane proteins that bind to chemical messengers and initiate a cellular response.

Glycosylation

The covalent addition of a carbohydrate to a lipid or protein.

Glycolipids

Lipids with a carbohydrate attached.

Glycoproteins

Proteins with a carbohydrate attached.

Cholesterol's role in membrane fluidity

Restricts the movement of phospholipids at warm temperatures and maintains fluidity at cool temperatures.