Getting Into and Out of Cells

Cell Transport

Types of Cell TransportPassive Transport - no cellular energy required to occur - goes with the concentration gradient

- diffusion- facilitated diffusion

- osmosisActive Transport - requires cellular energy to occur - goes against the concentration gradient

- Endocytosis/Exocytosis - Sodium Potassium Pump

Concentration GradientThe concentration gradient is the

distribution of particles across space from high to low concentration

Passive Transport Energy for passive transport comes from

the molecules themselvesIn passive transport, molecules move with

the concentration gradient - move from high concentration to low

concentration

DiffusionPrimary means of cell transport - molecules move from high to low

concentration - movement continues with the gradient

until the molecules are evenly distributed - equilibrium is achieved

Facilitated DiffusionParticles move with the concentration

gradient across a transport protein in the membrane

- ions, sugar and amino acids all move into and

out of cells by facilitated diffusion

OsmosisThe diffusion of water across a selectively

permeable membrane - water moves from where there is more

water to where there is less water - water moves toward higher conc. of

dissolved material - solute

Three osmotic environmentsHypotonic environment

Little(below) solute/lots of water

What happens when you place cells in an environment that is hypotonic to it? Hmm

Animal Cell Plant Cell

Hypotonic Environment Animal Cell Plant Cell

Before Water Moves In

Afterburst turgid

2nd type of Environment

HypertonicLots of solute/little water

What happens when you place a cell in an environment that is hypertonic to it? hmm

Hypertonic environmentAnimal Cell Plant Cell

Before Water Moves Out

shrinks

plasmolyze

3rd EnvironmentIsotonic Environment

Equal amounts of solute and water

What happens to a cell in an isotonic environment? hmm

Isotonic Environment Animal Before Plant

Water Moves In and Out at an equal rate

No Change After No Change