diffusion and osmosis

• Diffusion


  Gradual movement of particles from high to low concentration
• Concentration Gradient


  Difference in concentration affecting diffusion rate
• Cell Membranes


  Allow passage of small molecules like oxygen and glucose
• Osmosis


  Movement of water across a partially permeable membrane
• Partially Permeable Membrane


  Allows only small molecules like water to pass through
• Sucrose


  Type of sugar solution affecting osmosis
• Net Movement of Water Molecules

  Flow of water from higher to lower concentration in osmosis
• Plant Tissue Experiment


  Demonstrates osmosis effects on mass change in cylinders
• Dependent Variable


  Chip mass in the osmosis experiment
• Independent Variable


  Concentration of sugar solution in the osmosis experiment
• Active Transport


  Absorption of substances against concentration gradient
• Gas Exchange


  Transfer of oxygen and carbon dioxide between cells and environment.
• Urea


  Waste product from protein breakdown removed by kidneys.
• Surface Area to Volume Ratio

  Factor determining ease of substance exchange based on organism size.
• Alveoli


  Air sacs in lungs for gas exchange with thin walls and large surface area.
• Villi


  Tiny projections in small intestine increasing surface area for nutrient absorption.
• Stomata


  Small holes on leaf underside allowing gas exchange.
• Guard Cells


  Cells controlling stomata opening to regulate water loss.
• Gills


  Fish gas exchange surface with lamellae and large surface area.
• Gill Filaments


  Thin plates in fish gills increasing surface area for gas exchange.
• Exchange Surfaces


  Structures adapted for efficient diffusion of gases or nutrients.