Membranes and Transport - Lecture Notes

This set of flashcards covers key vocabulary related to biological membranes and transport mechanisms as discussed in the lecture.

Biological Membranes

Consist of lipids and proteins assembled into a thin film, separating the cell from its surroundings.

Integral Membrane Proteins

Proteins embedded in the phospholipid bilayer that are involved in various cellular functions such as transport and signaling.

Peripheral Membrane Proteins

Proteins attached to the membrane surface, often playing roles in signaling or maintaining the cell's shape.

Phospholipid Bilayer

A double layer of phospholipids that forms the basic structure of biological membranes.

Hydrophilic

Attracted to water; refers to the polar end of phospholipids.

Hydrophobic

Repelled by water; refers to the nonpolar fatty acid tails of phospholipids.

Simple Diffusion

The passive movement of molecules from an area of higher concentration to an area of lower concentration through a membrane.

Facilitated Diffusion

The process of transporting molecules across a membrane via protein channels without the use of energy.

Active Transport

The movement of molecules across a membrane against their concentration gradient, requiring energy.

Osmosis

The diffusion of water across a selectively permeable membrane, responding to solute concentration differences.

Tonicity

The ability of a solution to affect the shape of cells by altering their internal water volume.

Endocytosis

The process by which cells internalize substances from the external environment.

Exocytosis

The process by which cells expel materials in vesicles that fuse with the plasma membrane.

Membrane Potential

The electrical potential difference across a cell membrane due to the distribution of ions.

The Sodium/Potassium Pump

A primary active transport protein that moves sodium out of and potassium into cells, evaluating membrane potential.

Secondary Active Transport

Transport that is driven by an ion concentration gradient established by primary active transport.

Transport proteins

form channels that allow selected polar

molecules and ions to pass across a membrane

Recognition proteins

in the plasma membrane identify a cell

as part of the same individual or as foreign

Receptor proteins

recognize and bind molecules from other

cells that act as chemical signals, such as hormones

Cell adhesion proteins

bind cells together by recognizing and

binding receptors or chemical groups on other cells

Fluid mosaic model

proposes that the membrane consists

of a fluid phospholipid bilayer in which proteins are embedded

and float freely

Primary active transport

The protein that transports a substance also hydrolyzes ATP to power

the transport directly.
Transports positively charge ions across membranes

Calcium Pump

moves Ca2+ from the

cytoplasm to the cell exterior, and from the cytosol into the

vesicles of the endoplasmic reticulum