~Cell Membrane Structure and Function

These flashcards cover key terms and concepts related to cell membrane structure and function, focusing on the properties, composition, and transport mechanisms associated with membranes.

Plasma membrane

Surrounds the cell and regulates the passage of substances.

Amphipathic

Molecules like phospholipids that have both hydrophobic and hydrophilic regions.

Fluid Mosaic Model

A model describing the structure of cell membranes, proposing that proteins are embedded within the lipid bilayer.

Membrane fluidity

The ability of biological membranes to move freely in two dimensions, affected by temperature and lipid composition.

Saturated fatty acids

Fatty acids that contain no double bonds, leading to less fluidity in membranes.

Unsaturated fatty acids

Fatty acids that contain one or more double bonds, increasing membrane fluidity.

Integral proteins

Proteins that are embedded in the cell membrane and can only be removed by chemical means.

Peripheral proteins

Proteins that are not embedded in the membrane but are attached to its surface through ionic or hydrogen bonding.

Diffusion

The movement of particles from an area of high concentration to an area of low concentration.

Osmosis

A type of diffusion specifically for water across a semipermeable membrane.

Isotonic solution

A solution where two sides have the same osmotic pressure, resulting in no net movement of water.

Hypertonic solution

A solution with a higher concentration of solutes, causing cells to lose water and shrink.

Hypotonic solution

A solution with a lower concentration of solutes, potentially causing cells to swell and burst.

Facilitated diffusion

A type of passive transport that requires specific proteins to help move substances across the membrane.

Active transport

The process of moving substances against a concentration gradient, requiring energy, often from ATP.

Na+/K+ pump

An example of active transport that moves sodium and potassium ions across the membrane against their concentration gradients.