Cell Membranes (I)

These flashcards cover vocabulary and essential definitions related to cell membranes, their structure, properties, and functions, aiding in understanding membrane dynamics and transport.

Phospholipid Bilayer

A double layer of phospholipids that constitutes the primary structure of cell membranes.

Fluid Mosaic Model

A model describing the structure of cell membranes where components are in constant movement, creating a mosaic-like pattern.

Transmembrane Proteins

Proteins that span across the phospholipid bilayer and are involved in a variety of cell functions including transport and signal transduction.

Hydrophilic

Substances that are attracted to water and can interact with water, typically polar molecules.

Hydrophobic

Substances that repel water and do not easily mix with it, typically nonpolar molecules.

Saturated Fatty Acids

Fatty acids with no double bonds between carbon atoms, leading to straight chains that can pack tightly.

Unsaturated Fatty Acids

Fatty acids with one or more double bonds in the carbon chain, resulting in bends that prevent tight packing.

Selectively Permeable

A property of membranes that allows some substances to pass through while blocking others.

Osmosis

The passive movement of water molecules through a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water.

Hypotonic Solution

A solution that has a lower concentration of solutes compared to another solution, leading to water entering the cell.

Hypertonic Solution

A solution that has a higher concentration of solutes compared to another solution, leading to water leaving the cell.

Isotonic Solution

A solution where the concentration of solutes is equal inside and outside the cell, resulting in no net movement of water.

Facilitated Diffusion

The process of passive transport of molecules across a membrane via specific transmembrane integral proteins.

Channel Proteins

Proteins that provide passageways for specific molecules and ions to pass through the cell membrane.

Carrier Proteins

Proteins that bind to specific molecules and change shape to transport them across the membrane.

Active Transport

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

Passive Transport

The movement of substances across a cell membrane without the use of energy, typically down a concentration gradient.

Concentration Gradient

A difference in concentration of a solute between two areas, leading to movement from high to low concentration.

Cholesterol

A lipid that is inserted into the phospholipid bilayer to maintain membrane fluidity, especially at different temperatures.