8 OsmosisThe diffusion of water across a selectively permeable membrane.Osmosis is a type of Passive Transport.Osmosis requires NO ENERGY.
9 OsmosisHypertonic- a solution that causes a cell to shrink because of Osmosis.Hypotonic- a solution that causes a cell to swell because of Osmosis.Isotonic- a solution that causes no change in the size of the cell
10 OsmosisIn this picture a red blood cell is put in a glass of distilled water. Because there is a higher concentration of water outside the cell, water enters the cell by OSMOSIS. In this case too much water enters and the cell swells to the point of bursting open.
11 Selectively Permeable A membrane that allows only certain materials to cross itMaterials pass through pores in the membrane
12 SummaryDiffusion is the movement of molecules from an area of higher concentration to an area of lesser concentration.Osmosis is the movement of water thru a semi permeable membrane.Active transport requires energy. (molecules move from an area of lesser to higher concentration)Passive transport needs NO ENERGY! (molecules move from an area of higher to lesser concentration).
13 Why are osmosis & diffusion important? All living things have certain requirements they must satisfy in order to remain alive – maintain homeostasisThese include exchanging gases (usually CO2 and O2), taking in water, minerals, and food, and eliminating wastes.These tasks happen at the cellular level.Molecules move through the cell membrane by diffusionA balance, or EQUILIBRIUM, must be maintained.
14 10/10/13Do Now: What would you think the difference is between active and passive transport?HW:Read pages 55-56Complete “Check Your Understanding” on page 57
15 Active and Passive Transport Passive Transport = The diffusion of certain molecules through the cell membrane occurs passively, or without help.Osmosis Takes place through passive transport.Active Transport = Movement through the cell membrane that is the opposite of diffusion and requires energy (ATP)
16 Cellular RespirationThe process by which cells release energy from food.Cellular respiration releases energy.Water and carbon dioxide are byproducts
17 10/11/13 Do Now: How do plants get energy? HW: Read pages 57-58 Complete “Check Your Understanding” on page 59
24 Describe Photosynthesis The process of changing light energy to chemical energyEnergy stored as sugarOccurs in plants and some algaePlants need light energy, CO2, and H2OTakes place in the chloroplasts, using chlorophyll, the green pigment in plants
26 What happens during photosynthesis? Plants capture light energy and use that energy to make glucoseSunlight provides the energy needed by chlorophyll to change molecules of carbon dioxide and water into glucoseOxygen is also released in this reaction
27 What happens during photosynthesis? Carbon dioxide enters the leaf through holes called stomataCO2 combines with the stored energy in the chloroplasts through a chemical reaction to make glucoseThe sugar is moved through tubes in the leaf to the roots, stems and fruits of the plantsSome of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue
33 What is Cellular Respiration? The release of chemical energy for use by cells.
34 What is Cellular Respiration? Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism has to transform the chemical energy into a a form that can be used by the organism.This process is cellular respiration.