Functions of the Cell Membrane
Hydrophobic
"Water-fearing"; pertaining to nonpolar molecules (or parts of molecules) that do not dissolve in water.
Hydrophilic
"water-loving"; pertaining to polar or charged molecules (or parts of molecules) that are soluble in water
Equilibrium
A state of balance among the components of a system (homeostasis).
Cholesterol
A steroid that is an important component of animal cell membranes and that acts as a precursor molecule for the synthesis of other steroids such as hormones.
Hypertonic
Having a higher concentration of solute than another solution.
Cell Membrane
A cell structure that controls which substances can enter or leave the cell.
Phospholipid Bilayer
A double layer of phospholipids that makes up plasma and organelle membranes
Selectively Permeable/Semi-Permeable
A feature and a function of the plasma membrane that is essential to maintain homeostasis by regulating the passage of some substances while preventing others from entering the cell.
Concentration
A measurement of how much solute exists within a certain volume of solvent
Fluid Mosaic Model
Membrane is a fluid structure with a "mosaic" of various proteins embedded in or attached to a bilayer of phospholipids.
Protein channel
proteins that provide passageways through the membrane for certain hydrophilic (water-soluble) substances such as polar and charged molecules
Hypotonic
Having a lower concentration of solute than another solution
Plasmolysis
As a plant cell loses water, it shrivels, and its plasma membrane pulls away from the cell wall
Cytolysis
Bursting of a cell
Isotonic
Describes a solution whose solute concentration is equal to the solute concentration inside a cell
Osmosis
Diffusion of water through a selectively permeable membrane
Passive Transport
Movement across the cell membrane that does not require energy from the cell
Diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
Facilitated Diffusion
Movement of specific molecules across cell membranes through protein channels.
Turgor Pressure
Pressure that water molecules exert against the cell wall
Receptor Molecule
Proteins that transmit information in and out of cells. They allow communication between cells., Proteins on the surface of the cell membrane that receive signals from the nervous and endocrine system. These are needed for your cells to communicate and work together.
Active Transport
The energy-requiring movement of substances across a biological membrane against a concentration gradient
