Exchange with the Environment Mod.A U.1 L.5 Cells in Action Exchange with the Environment Mod.A U.1 L.5

Types of Cell Transport Passive Transport – Diffusion - Osmosis Active Transport – Endocytosis - Exocytosis - Active Uptake

Passive Transport No energy needed Particles move along a concentration gradient In cells small particles easily move across the cell membrane e.g oxygen, CO2 Particles move from areas of high concentration to areas of low concentration Larger molecules move through protein channels , e.g. glucose

Diffusion Occurs with solids, liquids or gases Particles travel from areas that are crowded into areas that aren’t High to Low concentration Happens in cells: inside and out

Demonstrations of Diffusion Perfume or room deodorizer Food coloring Cotton ball in plastic container Cell projects This type of particle movement requires NO energy

Factors affecting Diffusion 1. Temperature 2. Size of particles 3. Concentration Gradient Factors affecting Diffusion

Osmosis A special kind of diffusion The diffusion of water molecules Always happens through a semi-permeable membrane Only water molecules involved

When the molecules are evenly distributed throughout a space - it is called EQUILIBRIUM

Demonstrations of Osmosis The Greedy Grape The Iodine into a starch solution Potatoes in distilled water Celery sticks (Draw diagrams of each demo)

In Cells The cell membrane Is semi-permeable, bi-lipid Controls what enters and leaves cell

Vocabulary Isotonic: Same concentration – in equilibrum Hypertonic: Higher concn. of solute Hypotonic: Lower concn. of solute

Active Transport Energy needed Moves across a membrane against a concentration gradient From area of LOW concentration to areas of higher concentration 2 main types: Transport Proteins Endocytosis / Exocytosis

Transport Proteins Proteins in cell membrane use energy to pick up and carry molecules across the membrane e.g calcium, sodium, potassium,

2. Endocytosis and Exocytosis

Endocytosis – Solids Phagocytosis - Liquids

Answer these Questions in your ntbk. Describe 3 methods by which substances can move into and out of the cells How are passive transport and active transport similar? How are they different? Why is small size an advantage to a cell? Thinking Critically – Predicting. A single celled organism is transferred from a tank of fresh water into a tank of salt water. How will the cell change? Explain.