Chapter 3


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Chapter 3

  1. 1. Chapter 3 Biochemistry
  2. 2. Water <ul><li>Water has 4 important properties. </li></ul><ul><li>Water is polar. </li></ul><ul><li>Water has hydrogen bonding. </li></ul><ul><li>Water is cohesive. </li></ul><ul><li>Water is adhesive. </li></ul>
  3. 3. Polarity <ul><li>Many of water’s biological functions stem from its chemical structure. </li></ul><ul><li>The hydrogen and oxygen in water share electrons with covalent bonds. </li></ul><ul><li>These atoms do not share the electrons equally. </li></ul><ul><li>Since the oxygen atom is bigger than the hydrogen atoms, the electrons tend to hang around the oxygen atom more often. </li></ul><ul><li>This gives oxygen a small negative charge and the hydrogen a small positive charge. </li></ul>
  4. 4. <ul><li>A polar molecule is when opposite ends have opposite charges. Not charges like ionic bonds but smaller attractions that sometimes only water has. </li></ul>
  5. 5. Being polar leads to other things like……… <ul><li>Hydrogen bonds </li></ul><ul><li>This occurs when the slightly positive hydrogen atom is attracted to a slightly negative oxygen atom of another water molecule, it is a very weak attraction. </li></ul>hydrogen oxygen
  6. 6. Cohesion <ul><li>This occurs when molecules of the same kind stick to one another </li></ul>
  7. 7. Cohesion creates surface tension. Water is very sticky!
  8. 9. Adhesion <ul><li>This is when molecules that are not alike are attracted, example, water to walls of a test tube, or plant walls </li></ul><ul><li>When you see adhesion, think adhesive, sticky. </li></ul>
  9. 11. Capillarity <ul><li>This is when water goes up a small, narrow tube like a plant stem or paper towel. </li></ul><ul><li>Adhesion makes this possible. </li></ul>
  10. 12. Water’s Unique Properties <ul><li>Water has 4 unique properties. </li></ul>1 Water is polar. 2 Water makes hydrogen bonds. 3 Water is cohesive. 4 Water is adhesive.
  11. 13. Density of Water is Special!
  12. 14. <ul><li>Water is one of the only substances on Earth in which the solid phase is less dense than the liquid phase! </li></ul><ul><li>Because of this, life can exist in many places. </li></ul>
  13. 15. When winter comes, the ice floats and keeps fish safe. ICE Ouch!
  14. 16. If ice was actually denser than water……. I wish I could get to safer water below!
  15. 17. Temperature Moderation <ul><li>Water must gain or lose a relatively large amount of energy for its temperature to change. </li></ul><ul><li>When water is heated, most of the thermal energy that the water initially absorbs breaks the hydrogen bonds between the molecules. </li></ul><ul><li>When the bonds are broken, the thermal energy is released and increases the motion of the molecules. </li></ul><ul><li>Water’s ability to absorb large amounts of energy helps keep cells at an even temperature despite temperature changes in the environment. </li></ul>
  16. 18. Carbon Compounds <ul><li>A carbon atom has 4 electrons in its outer level which means it can create 4 bonds with any other atoms including itself. </li></ul><ul><li>This makes carbon an excellent backbone for many organic molecules. </li></ul><ul><li>Carbon can even form rings and double and triple bonds! </li></ul>
  17. 20. Functional Groups <ul><li>A functional group is a group of atoms that influence the properties of the molecules they compose. </li></ul><ul><li>Alcohol is a functional group that has oxygen and hydrogen attached. </li></ul><ul><li>Alcohols can cause blindness or even death when consumed. </li></ul><ul><li>Some alcohols are important to assemble certain molecules in the body. </li></ul>
  18. 22. Large Carbon Molecules <ul><li>In large carbon compounds, the molecules are built up from smaller, simpler molecules called monomers. </li></ul><ul><li>Monomers can bind together to create larger, more complex molecules called polymers. </li></ul><ul><li>Large polymers are called macromolecules. </li></ul>
  19. 23. How are polymers made and broken? <ul><li>Monomers link together in a condensation reaction. </li></ul><ul><li>When two monomers combine, water is released. </li></ul><ul><li>When polymers are broken, it is called a hydrolysis reaction. </li></ul><ul><li>Water is broken into two parts and breaks the bonds that holds the monomers together. </li></ul>
  20. 26. Energy Currency <ul><li>Life processes require energy. </li></ul><ul><li>This energy is available to life in the form of a compound called ATP. </li></ul><ul><li>ATP has three phosphates on the molecule and when one phosphate is broken off, energy is released. </li></ul>
  21. 29. Carbohydrates <ul><li>A monomer of a carbohydrate is called monosaccharide. </li></ul><ul><li>A monosaccharide is a simple sugar. </li></ul><ul><li>Two monosaccharides form a disaccharide. </li></ul><ul><li>A polysaccharide is a complex molecule composed of three or more monosaccharides. </li></ul><ul><li>What are some carbs? </li></ul>
  22. 32. Proteins <ul><li>Proteins are organic compounds made from monomers called amino acids. </li></ul><ul><li>There are 20 different amino acids. </li></ul><ul><li>The differences between the amino acids are their R groups. </li></ul><ul><li>Two amino acids bond to form a dipeptide. </li></ul><ul><li>In a condensation reaction, two amino acids form a covalent bond called a peptide bond. </li></ul><ul><li>Long chains of amino acids are called polypeptides. </li></ul><ul><li>What are some proteins? </li></ul>
  23. 34. Enzymes are a special kind of protein. <ul><li>Enzymes are proteins that are important catalysts for chemical reactions. </li></ul><ul><li>Enzyme reactions depend on the physical fit between the enzyme and the substrate. </li></ul><ul><li>The substrate is the reactant being catalyzed. </li></ul><ul><li>Enzymes may fail to work when the temperature isn’t correct. </li></ul><ul><li>Other chemicals and pH are also a factor. </li></ul>
  24. 36. Affects on Enzymes <ul><li>Temperature-raising of lowering temperature can cause an enzyme to malfunction </li></ul><ul><li>Denature-a protein unravels when it gets too hot </li></ul><ul><li>A change in pH can decrease the ability of an enzyme to function. </li></ul><ul><li>A foreign chemical or metal can decrease the ability of an enzyme to function. </li></ul>
  25. 37. Lipids <ul><li>Lipids are large, non polar molecules that do not dissolve in water. </li></ul><ul><li>Fatty acids are unbranched carbon chains that make up most lipids. </li></ul><ul><li>Hydrophilic-water-loving, molecules dissolve in water </li></ul><ul><li>Hydrophobic-water-fearing, molecules do not dissolve in water </li></ul>
  26. 38. Types of Lipids <ul><li>A triglyceride is composed of three molecules of fatty acids joined to an alcohol called glycerol. </li></ul><ul><li>Phospholipids have two fatty acids joined with glycerol. </li></ul><ul><li>Phospholipids are contained in the cell membrane and form a double layer to create a barrier between the inside and outside of cell. </li></ul><ul><li>A wax is a type of structural lipid. </li></ul><ul><li>A steroid has 4 carbon rings. Cholesterol is an example. Steroids are also hormones and very important for life. </li></ul>
  27. 41. Types of Fats(Lipids) <ul><li>A saturated fat has all available bonds used by hydrogen. </li></ul><ul><li>Saturated fats are solid at room temperature and are all single bonded, straight chains </li></ul><ul><li>Unsaturated fats have a double bond which means not all available bonds are taken by hydrogen. </li></ul><ul><li>Unsaturated fats are generally liquid at room temperature and are healthier. </li></ul>
  28. 43. Nucleic Acids <ul><li>Nucleic acids are large and complex organic molecules that store important information in the cell. </li></ul><ul><li>RNA stores and transfers information to make proteins. </li></ul><ul><li>DNA contains information that is essential for cell activities. </li></ul><ul><li>Both RNA and DNA are composed of monomers called nucleotides. </li></ul><ul><li>A nucleotide has 3 components: a phosphate group, a sugar and a nitrogen base. </li></ul>
  29. 44. Nucleotide
  30. 45. DNA
  31. 46. Essential Questions <ul><li>1. Describe the structure of the water molecule. </li></ul><ul><li>2. What are two properties of water that are caused by hydrogen bonding? </li></ul><ul><li>3. What is an organic compound? </li></ul><ul><li>4. Define functional group and give an example. </li></ul>
  32. 47. Essential Questions <ul><li>5. How does a polymer form? </li></ul><ul><li>6. How does a polymer break down? </li></ul><ul><li>7. What are the 4 classes of organic compounds? Give an example of each. </li></ul><ul><li>8. Explain the relationship between enzyme and substrate. </li></ul><ul><li>9. What affects the ability of enzymes to work? </li></ul>