Cell Membrane Structure and Functions

These flashcards cover the main components and functions of the cell membrane, including transport mechanisms and the structure of membrane proteins.

Phospholipids

Molecules consisting of two hydrocarbon chains (hydrophobic) and a phosphate group (hydrophilic) that form the cell membrane.

Integral Proteins

Proteins embedded in lipids that may cross the membrane and act like gates to allow substances in and out of the cell.

Peripheral Proteins

Proteins located along the edge of the membrane, often acting as receptors for hormones.

Cholesterol

A component of the cell membrane that maintains its fluidity.

Carbohydrate Chains

Chains found on the outside of the cell involved in cell-to-cell recognition and hormone reception.

Fluid-Mosaic Model

Model describing the cell membrane as a fluid bi-layer of lipids with embedded proteins.

Passive Transport

Movement of substances across a cell membrane without the use of energy.

Diffusion

The spread of substances along a concentration gradient, from high to low concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Facilitated Transport

Transport of molecules or ions across a membrane via a carrier protein, following a concentration gradient.

Active Transport

Movement of molecules or ions across a membrane against a concentration gradient, requiring energy.

Endocytosis

Process where molecules are engulfed by the cell membrane and form a vesicle within the cell.

Exocytosis

Process where molecules produced in the cell are expelled via vesicles.

Hypotonic Solution

A solution with a lower concentration of solute compared to another solution, causing cells to swell.

Isotonic Solution

A solution with equal concentration of solute inside and outside the cell, leading to no net movement of water.

Hypertonic Solution

A solution with a higher concentration of solute compared to another solution, causing cells to shrink.

Glycoprotein

A protein with carbohydrate chains attached, involved in cell recognition and signaling.

Channel Protein

A type of integral protein that forms a channel to allow the passage of specific ions or molecules.

Carrier Protein

A type of protein that transports substances across the cell membrane by changing shape.

Sodium-Potassium Pump

An active transport mechanism that moves sodium out of and potassium into the cell using ATP.

Proton Pumps

Active transport mechanisms that move protons (H+) across membranes to create an electrochemical gradient.