embrane Structure & Organelles

Mitochondrial Matrix

The inner compartment of a mitochondrion where the citric acid cycle occurs.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for ATP production.

Electron Transport Chain

A series of membrane proteins that transfer electrons and help establish a proton gradient.

Chloroplast

An organelle that performs photosynthesis in plants and photosynthetic algae.

Thylakoid

A membrane structure inside chloroplasts where light-dependent reactions occur.

Grana

Stacks of thylakoids inside chloroplasts.

Cholesterol

A membrane lipid that helps regulate membrane fluidity and stability.

Glycoprotein

A protein with an attached carbohydrate chain used in cell recognition, adhesion, or signaling.

Glycolipid

A lipid with an attached carbohydrate chain that helps with cell recognition and membrane interactions.

Carbohydrate Chain

A chain of sugars attached to a membrane protein or lipid that helps cells recognize and interact with other cells.

Peripheral Protein

A protein attached to the surface of a membrane.

Integral Protein

A protein embedded partly or completely in the cell membrane.

Transmembrane Protein

An integral protein that extends through the entire phospholipid bilayer.

Channel Protein

A protein that forms a pathway allowing specific substances to cross a membrane.

Carrier Protein

A protein that binds a substance and changes shape to transport it across a membrane.

Receptor Protein

A protein that binds signaling molecules and triggers cellular responses.

Ligand

A molecule that binds to a specific receptor or target protein.

Fluid Mosaic Model

A model describing the membrane as a fluid bilayer containing movable proteins and other molecules.