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Water and Solutions MAIN IDEA: The properties of water make it well suited to help maintain homeostasis in an organism. Do Now: Name one way our bodies use water to maintain homeostasis https://www.youtube.com/watch?v=HVT3Y 3_gHGg Properties of Water Water is polar; universal solvent Water is cohesive. Water is adhesive. Water is less dense as a solid. What is a solvent? What happens when you take kool-aid powder and pour it into a cup of water? Discuss with someone close to you; what is the solute? What is the solvent? Polarity polar molecules - molecules that have an unequal distribution of charges Polarity is the property of having two opposite poles. hydrogen bond - weak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom; happens b/c of polarity; strong type of van der Waals force Cohesive of water – attracted to each other b/c of H-bonds Causes surface tension Molecules Allows water to form droplets Allows insects to rest on water’s surface Adhesive Water forms Hbonds with molecules on other surfaces Allows water to travel up stems of plants (capillary action) Question… Is a meniscus an example of cohesion or adhesion? Discuss with someone close to you Ice is less dense than water As water cools to 4°C, it becomes more dense. When it freezes, it is less dense than liquid water. Nutrients in bodies of water mix. Animals live under frozen surface of bodies of water in winter. Question… What would happen in winter to animals that live in lakes if water was more dense as a solid? Think Discuss with someone next to you What is a mixture? Substances combine, but do not change chemically Can be separated easily No chemical change occurs Ex: tea, saltwater, salad dressing, bag of candy Types of Mixtures – mixture looks the same throughout Ex: salt water, soda Heterogeneous – mixture is different throughout Ex: salad, salad dressing Homogeneous Solutions Homogenous mixture Molecules of one substance mix evenly w/those of another (dissolves) 2 parts: – substance that is dissolved Solvent – substance that does the dissolving Name solute & solvent in salt water Solute Concentrations of solutions – less solute Concentrated – more solute Saturated – solution has as much solute as it can hold. Dilute Colloids 2 substances that don’t mix evenly Stay mixed Usually thicker than most liquids If light is shined through, it scatters – Tyndall effect Ex: fog, milk, jell-o, cream Tyndall Effect Suspension 2 substance that don’t mix evenly Do not stay mixed Particles – heavy and settle Ex: blood, flour and water, aerosols, ice cream Compare and contrast heterogenous and homogenous mixtures: Acids and Bases Acids Bases release hydrogen release hydroxide ions (H+) when ions(OH-) when dissolved in water dissolved in water Ex: stomach acid, Ex: ammonia, vinegar, citrus soap, blood fruit pH and buffers pH - measure of concentration of H+ in a solution Acidic solutions - pH values lower than 7. Basic solutions – pH values above 7. pH of 7 = neutral Buffer – mixtures that react with acids or bases to keep the pH in a neutral range Water Water pH = 7 (neutral) Water splits into H+ and OHEqual amounts of each Salts Formed when acid and base react Ex: NaOH + HCl NaCl + HOH base acid salt water Needed to control many life processes 6.4: The Building Blocks of Life MAIN IDEA: Organisms are made up of carbon-based molecules. Organic Chemistry Carbon is a component of almost all biological molecules. 4 electrons in outer energy level, so 4 electrons to share in 4 covalent bonds Carbon Carbon makes covalent bonds with other elements, like hydrogen, oxygen, and nitrogen (CHON) Carbon molecules – can be straight chains, branched chains, or rings Macromolecules Carbon atoms join to form carbon molecules. Macromolecules - large molecules formed by joining smaller organic molecules together. Polymers - molecules made from repeating units of identical or nearly identical compounds linked together by a series of covalent bonds. Each link - monomer Monomer Polymer 4 Main Organic Compounds Carbohydrates, lipids, proteins, and nucleic acids All needed for proper cell function and structure Carbohydrates Carbon, hydrogen, oxygen in ratio of 1:2:1 Ex: glucose = C6H12O6 Reduces to 1:2:1 (CH2O)n Key energy source in most foods Provides structural support in cells Ex: sugars and starches Monosaccharides Values of n ranging from three to seven are called simple sugars, or monosaccharides. (saccharide = sugar) Building blocks of carbohydrates Ex: glucose, fructose Longer Carbohydrates 2 monosaccharides = disaccharide More than 2 = polysaccharide Lipids Made mostly of carbon and hydrogen Nonpolar, so not soluble, or mostly insoluble, in water Types of Lipids Phospholipids – make cell membranes Steroids/sterols – ex: cholesterol – in animal cell membranes Pigments – ex: chlorophyll Fats, oils, and waxes Fats and Oils Store a LOT of energy Mostly C-H bonds, which have a lot of energy Structure usually – 3 fatty acids bonded to glycerol (called triglyceride) Fat if solid at room temp; oil if liquid at room temp Fatty acids Saturated fats = all C’s bonded to at least 2 H’s; single bonds between carbons; most animal fats (butter, lard, grease) Unsaturated = some double bonds between carbons (1 = monounsaturated; more than 1 = polyunsaturated); liquid at room temp (oils); healthier to eat Hydrogenated = H added to unsaturated fats to improve texture Proteins of amino acids – small carbon compounds made of CHONS (carbon, hydrogen, oxygen, nitrogen, sometimes sulfur) 20 different amino acids Made Amino Acid Structure Contain a central carbon atom One of carbon’s bond is to hydrogen The other three bonds are with an amino group (–NH2), a carboxyl group (–COOH), and a variable group (–R). Bond between 2 amino acids = peptide bond Complexity of Protein Structure structure – number and order of amino acids joined together Primary Chain of amino acids = polypeptide structure – chain folds into a 3-D shape: helix or pleat Secondary Protein Structure What are proteins for? – promote chemical reactions Structure of organisms: collagen (skin, ligaments, tendons..), bone, hair, muscles Provide antibodies and hormones Allow muscle contractions, blood clots Hemoglobin (carries oxygen in blood) Enzymes Nucleic Acids Store and transmit genetic information Ex: DNA and RNA Made of nucleotides – repeating units made of PCHON Sugar, base, phosphate group DNA and RNA- both have 4 types of nucleotides DNA – double helix (2 chains, spiral); genetic material RNA – one strand, makes proteins Fill in the blanks: KOH + HBr + H 2O HCl + KCl + H2O LiOH + HBr + ______ + ______ RbF + H2O ANSWERS! KOH + HBr KBr + H2O HCl + KOH KCl + H2O LiOH + HBr LiBr + H2O HF + RbOH RbF + H2O DO NOW Draw the atomic structure and the Lewis structure for magnesium (Mg). Is magnesium stable? If not, what should it do to become stable? Fill in the blanks: HF + LiOH + Energy, Work, and Order Energy = ability to do work or cause change Potential = stored energy Kinetic = energy of motion For work to occur, potential energy must be converted to kinetic energy Energy in Cells Energy is used for many things in cells: Moving substances Building new molecules Growth Reproduction Establishing and maintaining order Establishing/Maintaining Order Atoms/molecules arranged in specialized order Organization allows cells and systems to function properly EX: cells organized to tissues, organized into organs, and finally body systems. Takes ENERGY to maintain organization Energy and Order Cells, atoms, etc, WANT to be in a state of disorder Without energy, systems become simple/disorganized (entropy) Continual input of energy keeps a state of order Organisms = highly organized systems b/c of constant energy input Where is the energy from? Energy in Reactions Synthesis rxns use energy Often, they react very slowly Need catalysts Catalyst = substance that promotes chem rxns but is not affected/used up Enzyme = specialized catalyst in organisms. Photosynthesis Process by which autotrophs (producers) like plants (and some bacteria and green algae) make their own food Uses water, carbon dioxide, and energy from sunlight to make glucose (sugar) Takes place if organism has chlorophyll (green pigment) Usually happens in leaves Photosynthesis cont. Synthesis reaction Requires energy in form of sunlight Photosynthesis cont’d sunlight Water + carbon dioxide oxygen + glucose sunlight 6H2O + 6CO2 6O2 + C6H12O6 Glucose = sugar; stored as sugar to give plants energy, and starch to give consumers energy Photosynthesis cont’d Plants get water from roots, transported to leaves by xylem Stomata – “doorways” into leaves for gases CO2 in and O2 out Gases cannot pass through waxy part of leaf Sunlight captured in chloroplasts in cells, which produce chlorophyll (pigmentabsorbs light) Stomata Chloroplast Respiration Glucose energy Decomposition reaction Occurs in mitochondria ALL organisms go through respirationsome aerobic, some anaerobic Mitochondria: “the powerhouse” Respiration cont’d Glucose + oxygen carbon + water + energy dioxide C6H12O6 + 6O2 6CO2 + 6H2O + energy Energy Molecules Energy stored in ATP as chemical energy ATP: adenosine triphosphate ATP ADP ADP: andenosine diphosphate Remains when ATP is used Cycle replaces ATP supply 3 Steps of Respiration 1. 2. 3. Glycolysis Krebs Cycle Electron Transport System Glycolysis (pg. 397) Glyco = sugar Lysis = to split apart Glucose split in half Net 2 ATP Krebs cycle (pg. 399) 3-carbon molecules disassembled Carbon dioxide released Energy released – gain of 2 ATP (4 total so far) Hydrogen also released electron transport Electron Transport Chain (pg. 400) Hydrogen’s electrons transferred from carrier to carrier, releasing energy “Caught” by oxygen – makes water (released) 34 ATP gain (38 total) 44% energy from glucose ATP Only 25% of gas in car usable energy! Oxygen/Carbon Dioxide Cycle Oxygen is a waste product of photosynthesis, but is used in respiration. Carbon dioxide is a waste product of respiration, but is used in photosynthesis. Two Types of Chemical Rxns Synthesis Compounds are made Energy is required/used Ex: Making glucose (photosynthesis) Decomposition Compounds are broken down Energy is released Ex: breaking down food (digestion) Synthesis or Decomposition? Na + Cl NaCl NaCl Na + Cl Synthesis or Decomposition? Na + Cl NaCl synthesis NaCl Na + Cl decomposition Ionization Reactions Ionic bonds can separate in solution Ex: salt in water separates to Na+ and Cl- ions in the water Compounds NOT made of ions can undergo ionization Ex: water – not made of ions, but very few water molecules separate into ions Important for many life functions H2O H+ + OH- H2O H+ + OH H+ = hydrogen ion (H lost an e-, and now it’s only a proton) OH- = hydroxide ion (it has the e- lost by the hydrogen ion) Ionized water: hydrogen ions = hydroxide ions When hydrogen ions ≠ hydroxide ions, the solution is an acid or a base