The Chemistry of Life Polar Molecule: A molecule with one end having positive electrical charge and the other end having negative electrical charge. Water has “Polar Covalent” bonds. Hydrogen Bonds: ◦ A weak attraction between the hydrogen of one molecule and a slightly negative atom on another molecule. ◦ External Bond http://www.clearbiology.com/biochemistry-reviewactivity/ Color code the water molecules and hydrogen bonds the following: Blue = Oxygen Red = Hydrogen Yellow = Positive Pole Orange = Negative Pole Purple = Hydrogen Bonds Working with a partner you will follow the directions and record the observations you make. Cohesion & Adhesion An attraction between substances of the same kind. Hydrogen bonds between water molecules. Molecules at the surface of water are linked together by hydrogen bonds. Surface Tension: attraction between water molecules due to hydrogen bonds. An attraction between different substances. Capillary Action: Water moves upward due to adhesion of water to another surface. Ex: The water in the ground moves up a plant by being attracted to the walls of the tube in the stem bring water from roots to leaves. Cohesion & Adhesion https://www.youtube.com/watch?v=aVmU3CLxvgU Properties of Water 4:12 https://www.youtube.com/watch?v=ynk4vJa-VaQ Slo Mo Surface Tension 3:30 A B A What is occurring in A and B? – Be prepared to explain your response. Choices – Adhesion or Cohesion Summarize the property – define all key terms. Explain how property helps to support life. Include examples.