1. Passive TransportMovement of materials in and out of the
cellRequires no energy to happen
Two Types of Passive TransportDiffusion: When substance moves
that is dissolved in waterOsmosis: When water moves across the
membrane
Solutions are made of 2 parts:Solute: Substance that is
dissolved in waterSolvent: Liquid it is dissolved in (usually
water)
Next answer some questions about the pictures on your paper
Vocab:Hypertonic: More solutes than the other solutionHypotonic:
Less solutes than the other solutionIsotonic: Equal solutes as
another solutionNow go back to the pictures above and label the
cell and the environment around it as one of the vocab words
(a)(b)
Describing a solutionHypotonic: when a solution is less
concentrated than another solutionExample: if around a cell is
hypotonic, then water will move into the cell.Can cause a cell to
get so large it may burst (cytolysis)
Hypertonic: When a solution is more concentrated than another
solutionIf around a cell is hypertonic, water will move out of the
cell Can cause the cell to get very small (in plants will see
plasmolysis: wilting)
Isotonic: when two solutions have the same concentration (are at
equilibrium)Causes water to move in and out equallyThe cell
maintains its shape
OsmosisWater moves trying to balance out concentrationsGoes from
where there is more water to less water
What if..Environment around a cell is hypotonic. What direction
will the water move?
Salt?
What if..The environment around a cell is hypertonic.What
direction will the water move?
Salt?
2. Active TransportRequires energyGoes against the concentration
gradient (from lower concentration to higher concentration)
Figure 7.16The sodium-potassium pump: a specific case of active
transport
Sodium Potassium PumpCells usually have more sodium ions outside
and more potassium ions insidePump increases number of ions where
concentration is already high
When substances are too large to pass through the cell membrane,
use endocytosis or exocytosisMembrane folds around substances and
release into cell or out of cell
Figure 7.20 Exploring Endocytosis in Animal Cells
EndocytosisMaterial moved into cellForms vesiclePinocytosis:
LiquidsPhagocytosis: Solids
