Chapter 5

Movement of molecules from area of high concentration to area of lower concentration, down concentration gradient until equilibrium is achieved. More collision in high concentration Collision spread molecules down concentration gradient

Gases, food molecules and waste products removed out of cell.

Molecules Ions Atoms

When the molecules are evenly distributed

Selectively permeable, meaning it lets some substances through easily and others more difficult.

Obtain requirements Get rid of waste products Gas exchange

CO2, diffuse out of leaves through stomata. Lower concentration of CO2 in leaves as cells use up. O2 diffuse out of leaf

Attract pollinators Petals fragrance diffuse from leaf to air

Capillaries around alveoli have a high concentration of CO2, low concentration of O2. Alveoli high concentration of O2, low concentration of CO2. O2 diffuse from high concentration in alveoli to low concentration in blood. CO2 diffuses from high concentration in blood to low concentration in alveoli.

Products of digestion absorbed by ileum Solutes like glucose and amino acids can diffuse from ileum blood stream.

Water molecules high water to low water potential through a selectively permeable membrane down a water potential gradient.

Pure water, water move into cell endosmosis Pure water has a high water potential water potential Cell sap low water potential Plant cell expand vacuole swells, cell becomes turgid Cellulose wall expand slightly Higher water potential outside plant than inside cell sap, water enter cell

Concentrated salt solution, water move out - exosmosis Salt water lower - lower water potential Cell sap high water potential Cytoplasm, vacuole shrinks - flaccid Membrane tears , cell undergo plasmolysis Higher water potential in cell sap than outside, water exit

no cell walls Water move into cell by endosmosis Swell up and burst - cannot become turgid When in danger, certain structure will pump out water

Water move out of cell through exosmosis Cell shrinks Should always be surrounded by isotonic solution

Regulation of the concentration of water and salts in the body

Movement of water across the cell membrane to maintain water balance 1. Biological processes 2. Regulate water potential of cell Root from soil - without water potential gradient, water lost Not enough water, wilt - not enough pressure in cells to support plant structure Too much water, burst, brown spots on leaves Nutrients - need - dissolved in water Metabolic waste products dissolves in water.

Movement of particles (MIA) through cell membrane from area of high concentration to area of low concentration down concentration gradient using energy from respiration.