Biological Membranes and Transport

These flashcards cover key terms and concepts related to biological membranes and transport mechanisms as outlined in the lecture notes.

Biological Membranes

Sheet-like structures that form closed boundaries between compartments and separate cells from their external environment.

Amphipathic Molecules

Molecules that contain both hydrophobic and hydrophilic parts, essential in forming lipid bilayers.

Lipid Bilayer

The basic structural element of membranes composed primarily of lipids organized in two layers.

Fluid Mosaic Model

A model describing membranes as dynamic structures where lipids and proteins can move freely within the layer.

Facilitated Diffusion

A process that allows substances to cross membranes with the assistance of special proteins, typically down a concentration gradient.

Active Transport

The movement of molecules against their concentration gradient, requiring energy input, often in the form of ATP.

Ion Channels

Proteins that span the membrane and allow specific ions to flow across the membrane quickly and selectively.

Peripheral Membrane Proteins

Proteins that associate with the membrane primarily through electrostatic or hydrogen-bonding interactions.

Integral Membrane Proteins

Proteins that are embedded in the lipid bilayer and often span the entire membrane.

Lipid Rafts

Specialized regions within the membrane that have distinct lipid and protein compositions, often involved in signaling.

Primary Active Transport

Transport that uses energy directly from ATP to move ions or molecules against their concentration gradient.

Secondary Active Transport

Transport where the movement of one molecule depends on the movement of another molecule down its concentration gradient.