Membrane Transport and Cell Signaling

A comprehensive set of vocabulary flashcards covering key concepts related to membrane transport and cell signaling.

Plasma membrane

A selective barrier that regulates interactions between the cell and its environment.

Selective permeability

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

Phospholipid bilayer

A double layer of phospholipids that forms the structural foundation of cell membranes.

Amphipathic molecules

Molecules that have both hydrophobic (nonpolar) and hydrophilic (polar) regions.

Fluid mosaic model

A model that describes the cell membrane as a mosaic of various proteins embedded in a fluid lipid bilayer.

Transport proteins

Proteins that help transport substances across a cell membrane.

Passive transport

The movement of substances across a membrane without the need for energy investment.

Active transport

The movement of substances against their concentration gradient, requiring energy.

Facilitated diffusion

The process by which transport proteins help specific molecules cross the plasma membrane.

Osmosis

The diffusion of water across a selectively permeable membrane.

Isotonic solution

A solution with the same solute concentration as the cytoplasm of a cell, resulting in no net water movement.

Hypertonic solution

A solution with a higher solute concentration than inside the cell, resulting in water loss from the cell.

Hypotonic solution

A solution with a lower solute concentration than inside the cell, resulting in water gain by the cell.

Cotransport

A process in which secondary active transport couples the diffusion of one solute with the transport of another solute against its gradient.

Exocytosis

The process by which vesicles fuse with the plasma membrane to release their contents outside the cell.

Endocytosis

The process by which cells take in molecules by forming new vesicles from the plasma membrane.

Signal transduction pathway

A series of molecular events and reactions that lead to a cellular response following a signal molecule binding to a receptor.

G protein-coupled receptors (GPCRs)

Membrane receptors that work with the help of G proteins to transmit signals inside the cell.

Second messengers

Small, nonprotein molecules or ions that relay signals within the cell, such as cyclic AMP.

Protein phosphorylation

The process of adding a phosphate group to a protein, which can change its activity.

Transcription factor

A molecule that helps regulate the transcription of specific genes by binding to nearby DNA.