Ch. 5 Membrane Structure, Synthesis, and Transport

Feb. 4

Fluid Mosaic Model

A model used to describe the structure of the cell membrane. It suggests that the membrane is composed of a flexible and dynamic arrangement of lipid molecules (mostly phospholipids) with proteins interspersed throughout, resembling a mosaic. The lipids and proteins can move sideways, giving the membrane its fluid nature

Phospholipids

A type of lipid molecule that is a major component of cell membranes. They have a hydrophilic (water-attracting) "head" and two hydrophobic (water-repelling) "tails". This structure allows them to form bilayers in water, with the hydrophobic tails facing inward and the hydrophilic heads facing outward, creating the membrane’s basic structure.

Amphipathic

Describes a molecule that has both hydrophilic (water-loving) and hydrophobic (water-fearing) parts. Phospholipids are amphipathic because their heads are hydrophilic and their tails are hydrophobic, which allows them to form the bilayer structure of cell membranes.

Integral Proteins

Membrane proteins that are embedded within the lipid bilayer of the cell membrane. These proteins can span the entire membrane (transmembrane proteins) or be partially embedded. They are involved in a variety of functions like transport, signaling, and acting as receptors.

Peripheral Proteins

Membrane proteins that are not embedded in the lipid bilayer but are loosely attached to the outer or inner surface of the membrane. They often play a role in signaling, cell recognition, or maintaining the cell’s shape.

Endoplasmic Reticulum (ER)

An extensive network of membranes in eukaryotic cells that is involved in protein and lipid synthesis. The rough ER has ribosomes on its surface and is involved in protein production, while the smooth ER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.