Water and Solutions

1. Water and Solutions MAIN IDEA: The properties of water make it well suited to help maintain homeostasis in an organism.

2. Do Now: Name one way our bodies use water to maintain homeostasis https://www.youtube.com/watch?v=HVT3Y3_gHGg

3. Properties of Water • Water is polar; universal solvent • Water is cohesive. • Water is adhesive. • Water is less dense as a solid.

4. 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?

5. 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

8. Cohesive • Molecules of water – attracted to each other b/c of H-bonds • Causes surface tension • Allows water to form droplets • Allows insects to rest on water’s surface

9. Adhesive • Water forms H-bonds with molecules on other surfaces • Allows water to travel up stems of plants (capillary action)

10. Question… Is a meniscus an example of cohesion or adhesion? Discuss with someone close to you

11. 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.

12. 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

14. 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

15. Types of Mixtures • Homogeneous – mixture looks the same throughout • Ex: salt water, soda • Heterogeneous – mixture is different throughout • Ex: salad, salad dressing

16. Solutions • Homogenous mixture • Molecules of one substance mix evenly w/those of another (dissolves) • 2 parts: • Solute – substance that is dissolved • Solvent – substance that does the dissolving • Name solute & solvent in salt water

17. Concentrations of solutions • Dilute – less solute • Concentrated – more solute • Saturated – solution has as much solute as it can hold.

18. 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

19. Tyndall Effect

20. Suspension • 2 substance that don’t mix evenly • Do not stay mixed • Particles – heavy and settle • Ex: blood, flour and water, aerosols, ice cream

21. Compare and contrast heterogenous and homogenous mixtures:

22. Acids release hydrogen ions (H+) when dissolved in water Ex: stomach acid, vinegar, citrus fruit Bases release hydroxide ions(OH-) when dissolved in water Ex: ammonia, soap, blood Acids and Bases

23. 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

24. Water • Water pH = 7 (neutral) • Water splits into H+ and OH- • Equal amounts of each

26. Salts • Formed when acid and base react • Ex: NaOH + HCl  NaCl + HOH • base acid salt water • Needed to control many life processes

27. 6.4: The Building Blocks of Life MAIN IDEA: Organisms are made up of carbon-based molecules.

28. 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

29. Carbon • Carbon makes covalent bonds with other elements, like hydrogen, oxygen, and nitrogen (CHON) • Carbon molecules – can be straight chains, branched chains, or rings

30. 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

31. Monomer

32. Polymer

33. 4 Main Organic Compounds • Carbohydrates, lipids, proteins, and nucleic acids • All needed for proper cell function and structure

34. 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

35. Monosaccharides • Values of n ranging from three to seven are called simple sugars, or monosaccharides. (saccharide = sugar) • Building blocks of carbohydrates • Ex: glucose, fructose

36. Longer Carbohydrates • 2 monosaccharides = disaccharide • More than 2 = polysaccharide

37. Lipids • Made mostly of carbon and hydrogen • Nonpolar, so not soluble, or mostly insoluble, in water

38. Types of Lipids • Phospholipids – make cell membranes • Steroids/sterols – ex: cholesterol – in animal cell membranes • Pigments – ex: chlorophyll • Fats, oils, and waxes

39. 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

41. 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

42. Proteins • Made of amino acids – small carbon compounds made of CHONS (carbon, hydrogen, oxygen, nitrogen, sometimes sulfur) • 20 different amino acids

43. 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

44. Complexity of Protein Structure • Primary structure – number and order of amino acids joined together • Chain of amino acids = polypeptide • Secondary structure – chain folds into a 3-D shape: helix or pleat

45. Protein Structure

46. What are proteins for? • Enzymes – 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)

47. 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

50. Fill in the blanks: • KOH + HBr  + H2O • HCl +  KCl + H2O • LiOH + HBr  + • ______ + ______  RbF + H2O