Cell Communication

Selectively Permeable

A property of cell membranes that allows certain molecules to pass through while blocking others.

Diffusion

The passive process of movement of molecules from an area of higher concentration to an area of lower concentration.

Equilibrium

A state in which opposing forces or influences are balanced, resulting in no net movement of molecules.

Simple Diffusion

The process of molecules diffusing across membranes without assistance from transport proteins.

Facilitated Diffusion

The process by which molecules diffuse across membranes with the help of transport proteins.

Channel Proteins

Proteins that form fluid-filled tunnels in the membrane, allowing small hydrophilic molecules to pass through.

Carrier Proteins

Proteins that transport specific molecules across membranes by changing shape.

Osmosis

The diffusion of water from an area of higher concentration to an area of lower concentration.

Hypertonic

A solution with a greater concentration of solutes.

Hypotonic

A solution with a lesser concentration of solutes.

Isotonic

A solution with the same concentration of solutes as another solution.

Active Transport

The process of moving molecules against their concentration gradient requiring energy, usually in the form of ATP.

Sodium-Potassium Pump

A pump that moves three sodium ions out of the cell and two potassium ions into the cell, crucial for maintaining cell potential.

Cell-cell Attachments

Connections between cells that allow them to form tissues and communicate.

Tight Junctions

Connections that hold cells tightly together to prevent water and other molecules from passing between them.

Anchoring Junctions

Structures that hold cells together tightly, allowing materials to move through intercellular spaces.

Desmosomes

Anchoring junctions that connect cells via cadherins and intermediate filaments.

Hemidesmosome

Anchoring junctions that connect cells to the extracellular matrix.

Adherens Junctions

Connections between cells and the extracellular matrix formed by cadherins and actin filaments.

Communicating Junctions

Junctions that allow for the direct passage of chemical or electrical signals between cells.

Plasmodesmata

Channels between plant cells that allow for transport and communication.

Hormones

Signals that travel long distances to reach target cells.

Receptors

Proteins that bind signaling molecules and trigger cellular responses.

Signal Transduction

The process by which a signal on a cell's surface is converted into a specific cellular response.

Primary Messenger

The initial signaling molecule that binds to a receptor.

Second Messengers

Molecules that amplify and spread the original signal within a cell.

Phosphorylation

The addition of a phosphate group to a molecule, often regulating its activity.

Kinases

Enzymes that transfer phosphate from ATP or GTP to other molecules.

Receptor Tyrosine Kinases (RTKs)

A family of receptors that catalyze phosphorylation of tyrosine residues on target proteins.

G Proteins

Proteins that bind GTP and are involved in transmitting signals from receptors to target proteins.

Phosphatases

Enzymes that remove phosphate groups from molecules, inactivating them.

Deactivating Signals

Mechanisms that terminate cellular responses to signals.

ATP

A molecule that serves as the primary energy currency of cells.

Cellular Homeostasis

The maintenance of stable internal conditions in a cell.

Transport Proteins

Proteins that facilitate the movement of substances across a cell membrane.

Hydrophobic

Molecules that do not interact well with water.

Hydrophilic

Molecules that have an affinity for water and can interact with it.

Concentration Gradient

A difference in the concentration of a substance across a space.

Endocytosis

The process by which cells take in substances by enveloping them in a membrane.

Exocytosis

The process of vesicles fusing with the plasma membrane to release their contents outside the cell.

Signal Amplification

The process whereby a single signaling molecule can produce a larger cellular response.

Membrane Potential

The difference in electrical charge across a membrane.

Cell Communication

The process by which cells send and receive signals to coordinate functions.

Multicellular Organism

An organism composed of many cells that often communicate for coordinated function.

Intermediate Filaments

Cytoskeletal components that provide structural support to cells.

Cytoskeleton

A network of filaments and tubules that aids in cell shape, transport, and movement.