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Biochemist ry Unit 5 Slide 2 Biochemistry life chemistry Its all about theyou eat, and the & that we obtain from eating them!! Its all about the foods you eat, and the molecules & energy that we obtain from eating them!! Slide 3 One of the most importan t molecule s in living systems! One of the most importan t molecule s in living systems! WATER Slide 4 Lets discuss how this molecule is formed Slide 5 WATER is an example of a molecule that is covalently bonded Slide 6 covalently bonded = sharing electrons Slide 7 What is a covalent bond? Electrons are shared among two or more atomsElectrons are shared among two or more atoms Slide 8 Do you remember the ionic bond? Electrons are either given or taken among two or more atoms Their opposite charges, bring them together Slide 9 Lets Practice a few covalent bonds: Slide 10 e- spend more time around the oxygen e- spend less time around the hydrogens Slide 11 e- spend more time around the oxygen e- spend less time around the hydrogens Slide 12 CREATES a POLAR molecule Two poles (ends) Opposite charges Slide 13 Slide 14 Properties of Water that contribute to its importants for life: Cohesion 1) Cohesion *Water attracted to other water molecules Slide 15 Properties of Water that contribute to its importants for life: Cohesion 1) Cohesion * Water attracted to other water molecules b/c of a hydrogen bond!! Slide 16 The Hydrogen bond: * Water attracted to Water - - - - - + + + ++ + + + + + b/c of a hydrogen bond!! Slide 17 Properties of Water that contribute to its importants for life: Cohesion 1) Cohesion *Water attracted to other water molecules Slide 18 results in Surface Tension results in Surface Tension -` *Cohesion of water molecules to eachother at the surface of the body of water. Difficult to stretch or break surface Properties of Water that contribute to its importants for life: Slide 19 results in Surface Tension results in Surface Tension - *Cohesion of water molecules to eachother at the surface of the body of water. Properties of Water that contribute to its importants for life: Slide 20 results in Surface Tension results in Surface Tension - Properties of Water that contribute to its importants for life: Slide 21 Slide 22 Slide 23 Adhesion - 2) Adhesion - water attracted to other surfaces makes water sticky Slide 24 WHAT is going on here? Slide 25 Properties of Water that contribute to its importants for life: Adhesion - 2) Adhesion - water attracted to other surfaces makes water sticky Slide 26 Slide 27 This is a sea bird that died as a result of an oil spill This is a sea bird that died as a result of an oil spill Explain why??? (use: H-bond, polar, surface tension in your answer) Explain why??? (use: H-bond, polar, surface tension in your answer) Slide 28 Adhesion + Cohesion results in capillarity Adhesion + Cohesion results in capillarity - *molecules moving against gravity (upward). Think of a plant from root to leaf Slide 29 Slide 30 Slide 31 Specific Heat of water is high 3) Specific Heat of water is high - amount of heat needed to raise or lower temp by 1 o C - takes a lot of heat for water Properties of Water that contribute to its importants for life: Slide 32 Specific Heat 3) Specific Heat = (high) - takes a lot for water b/c the thermal energy is absorbed in the H- bonds BEFORE it increases motion of the water molecule Properties of Water that contribute to its importants for life: Slide 33 Specific Heat Specific Heat = (high for water) - water does not heat up or cool down as fast as other substances Properties of Water that contribute to its importants for life: Slide 34 WHY does water heat up slower than the metal pan??? Ever try to touch the pan (before the water boils??) Slide 35 H- bonds in water have to break before the water can heat no H-bonds in the metal Ever try to touch a pan of water (before the water boils??) Slide 36 results in temperature moderation results in temperature moderation - *A body of water will change temperature less when it absorbs or looses a given amount of heat than another substance Takes a lot of heat to raise the temp. Slide 37 THANK goodness for that! Slide 38 As water cools (@ night) & reforms H-bonds Slide 39 Heat is given off (b/c it is leaving the water) coast does not cool off as fast as mainland Slide 40 results in temperature moderation results in temperature moderation - *When water cools, it FORMS H- bonds. This release of energy (heat) Less drop in temp during same amount of time Slide 41 results in: is high for water results in: heat of vaporization is high for water : causes evaporative cooling Keeps you from overheating Properties of Water that contribute to its importants for life: Slide 42 Slide 43 Slide 44 WHY SWEAT? Slide 45 Less dense as a solid than liquid 4) Less dense as a solid than liquid Properties of Water that contribute to its importants for life: - Oceans and Lakes do not freeze from bottom up b/c ice floats Slide 46 5) Water is versatile Solvent Properties of Water that contribute to its importants for life: R E ACID H + BASE L U E OH -