Membrane and Transport

Diffusion

Movement of particles or molecules from an area of high concentration to an area of low concentration

Osmosis

Diffusion of water across a selectively permeable membrane

Selectively pemeable membrane

A membrane that allows certain materials to pass through via special protein channels

Semi-permeable membrane

a membrane (as a cell membrane) that allows some molecules that are small enough to pass through but not others

Brownian motion

the chaotic movement of particles, caused by collision with other particles of the fluid in which they are dispersed

Dynamic Equilibrium

condition of continuous, random movement of particles but no overall change in concentration of substances/molecules

Hypertonic

A solution that has a higher concentration of solutes than another.

Hypotonic

A solution that has a lower concentration of solutes than another.

Isotonic

Two solutions that have an equal concentration of solutes.

Solute

substance that is dissolved in a solution

Solvent

the liquid that contains the dissolved solute in a solution.

plasma membrane (cell membrane)

Flexible, selectively permeable (having pores or openings) boundary that helps control what enters and leave the cell.

Facilitated Diffusion

this form of diffusion is regulated by protein channels in the membrane and requires no energy input from the cell

Active Transport

movement of molecules or ion into or out of the cell against its concentration gradient (from low to high) and requires an input of energy.

Hypertonic

the left side is _____ compared to the right side.

Hypotonic

The right side is _____ compared to the left side.

right, left, osmosis

Water will move from the _____ to the _____ by _____.

Hypotonic

The left side is _____ compared to the right side.

Hypertonic

The right side is _____ compared to the left side.

left, right, osmosis

Water will move from the _____ to the _____ by _____.

Phospholipid

molecule that makes up cell membranes. It has a hydrophilic "head" and two hydrophobic "tails".

Hydrophilic

water loving. substances that easily mix with water.

fluid mosaic model

Structural model of the plasma membrane where molecules (phospholipids, proteins, carbohydrates, etc.) are free to move sideways within a lipid bilayer.

Hydrophobic

water hating. substances that will not mix with water.

carrier proteins (transporters)

binds to specific chemical, changes shape, moves the specific chemical across the membrane

Active transport that requires energy (ATP)

intracellular

Located inside a cell.

extracellular

Located outside a cell.

concentration gradient

difference in the concentration of a substance from one location to another (like from outside the cell to inside the cell)

Transport Protein

Proteins within the cell membrane that function to move substances into or out of the cell.