BIOL 1441 1st Edition Lecture 3 Outline of Last Lecture I. Chemical bondsOutline of Current Lecture: part one of chapter 3I. Facts about waterII. Properties of waterCurrent LectureI. Facts a. Water supports all lifeb. Organisms are composed of mostly wateri. Humans are 70% waterc. Life on earth began with waterd. Cells are surrounded by watere. Cells are 70-95% waterf. Earth is 75% waterg. Water is the only substance that naturally exists in all 3 states (liquid, solid, gas)h. HYDROGEN BONDING IS RESPONSIBLE FOR WATER PROPERTIESi. Structure of wateri. Unique properties arise from attractions between polar molecules1. b/c of hydrogen bondingII. Water propertiesa. Cohesion: binds a substance togetheri. H2O molecules attracted to each other. H bondsii. Transport of water and dissolved nutrients against gravity in plantsiii. Water evaporates from leavesiv. Upward pull is transported throughout all cells down to rootsv. Adhesion: clinging of one substance to another1. Water adheres to walls of cellsvi. Surface tension: measure of how difficult it is to stretch or break the surface of a liquid1. Water has greater surface tension than most liquidsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2. Interfere between water and air ordered arrangement of water moleculesa. Behaves like an invisible film3. Creates wavesa. Waves are necessary for rapid oxygen diffusion in lakes andoceansb. Moderation of temperaturei. Heat bank-stores heatii. Water can lose and gain a lot of heat and not change tempiii. Kinetic energy: energy of motioniv. Heat: total amount of kinetic energy due to molecular motion in a body ofmatterv. Temperature: average of kinetic energyvi. Heat is a form of energy-depends on volume of mattervii. Average speed of molecules increase-temp increases viii. Heat and temp are related but not the same1. Ex. You have a higher temp than the ocean but the ocean has more heatix. Energy will flow from high to low concentration1. Heat will always pass to the cooler object until the 2 are the same temperaturea. Ex. Ice doesn’t add coolness to a drink: ice absorbs heat from warm liquidx. Water freezes- 0°Cxi. Water boils- 100°Cxii. Human body- 37°Cxiii. Room temp- 20-25°Cxiv. Refrigerator- 4°Cxv. Measure of heat:1. Calorie: amount of heat it takes to raise temp of 1 gram of water by 1°C2. Kilocalorie: 1000 cala. Calories on food packages3. Joule:a. 1J=.239 cal4. Specific heat: amount of heat that must be absorbed or lost for 1g of that substance to change its temp by 1°C5. Water specific heat: 1 cal/j/°C (because hydrogen bonding)a. Unusually high6. Beer: .6cal/g/°C7. Metal has much lower specific heata. Pot of water on stove, pot gets hot a lot faster than the water8. Heat absorbed: break Hbonds9. Heat released: forms Hbonds10. Night/winter: water releasing heat, warming the air11. Stabilizes ocean
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