Unit 3 notes


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Unit 3 notes

  1. 1. Augustine Mai, Isaac Mandefro Period 8Unit 3 NotesOrganic chemistry is the chemistry of carbon compounds.Majority of organic molecules found in living organisms can beclassified into one of four types:- carbohydrates - proteins- lipids -nucleic acidsFour most common elements found in living things:-Hydrogen -Carbon-Nitrogen -OxygenRoles:sulfur -in some amino acidscalcium -cofactor in some enzymesphosphorous - phosphate groups in ATPiron- in cytochromessodium- in membrane functionStructure of water Water is the solvent of life Almost all cells have water within and in surrounding environment. Hydrogen and oxygen atoms in a water molecule are held together by a polar covalent bond Polar covalent bonding results from unequal sharing of electrons Each oxygen–hydrogen bond is a polar covalent bond. Results in a slight negative charge at the oxygen end of the molecule and a slight positive charge at the end with the two hydrogen molecules Two ends of each water molecule have opposite charges so H2O molecules interact with each other in different ways.
  2. 2. Augustine Mai, Isaac Mandefro Period 8Properties of water and living organismsThermal Properties High Specific heat: water can absorb/ give off a lot of heat without changing the temperature too much Water is a coolant for the body Has high heat of vaporization; water absorbs a great deal of heat when it evaporates Internal body heat turns to perspiration, with evaporates from skin. Heat used to turn liquid into evaporation so perspiration is a cooling method by lowering temperature.Cohesive Properties H2O molecule- highly cohesive Cohesion: molecules of the same type are attracted to each other Attraction due to polar covalent bondingSolvent properties Excellent solvent of other polar molecules Most molecules found in/out of the cell are also polar (Includes Carbohydrates, Proteins, Nucleic Acids) Most lipids are non-polar Water is a medium in which biochemistry of a cell occursCarbohydrates, Lipids and Proteins Living things composed of a variety of molecules Molecule; (Sub-components) -Carbohydrates; (Monosaccharides); Sub-categories (Monosaccharides, disaccharides, polysaccharides)
  3. 3. Augustine Mai, Isaac Mandefro Period 8 -Lipids; (Glycerol and fatty acids) -Proteins(Polypeptide); (Amino Acids) -Nucleic Acids; (Nucleotides) All organic molecules contain carbon Not all carbon containing molecules are organicFunctions of carbohydrates in plants and animals Carbohydrates among most found biochem molecules in plants/animals Carbohydrates have different sizes (monosaccharide, disaccharide, etc.) Animals Glucose-chemical fuel for cell respiration (mono.) Lactose-Makes up some solutes in milk (di.) Glycogen-stores glucose in liver and muscles (poly.) Plants Fructose- found in many fruits; makes sweet(Mono.) Sucrose- often transported from leaves of plants to other locations in plants by vascular tissue (Di.) Cellulose- one of primary components in plant cell walls (Poly.)Role of Lipids Triglyceride lipids, solid then called fat, liquid then called oil Excess fat is stored in adipose cells Efficient for storing energy Stores twice as much chemical energy as carbohydrates Important for thermal insulation Special lipid- phospholipid makes up the double layer of all cell membranes
  4. 4. Augustine Mai, Isaac Mandefro Period 8Condensation and Hydrolysis Reactions Foods are chemically digested. The digestive enzymes that accomplish this are hydrolysing enzymes. Each reaction is called a hydrolysis and requires a molecule of water as a reactant. Water is always split in hydrolysis Ex. -hydrolysis of a disaccharide to two monosaccharides lactose + water → glucose + galactose -hydrolysis of a polysaccharide to many monosaccharides; starch + (many) water → (many) glucose Condensation reactions are the opposite of hydrolysis reactions In condensation reactions, the water molecules are products rather than reactantsDNA Structure Nucleotides are building blocks of DNA Each nucleotide of DNA is composed of a phosphate, deoxyribose sugar, and base 4 possible nitrogenous bases: adenine, thymine, guanine, cytosine DNA has double helix shape Base pairs are adenine, thymine and guanine, cytosine Adenine and thymine are held together by two hydrogen bonds. Cytosine and guanine are held together by three hydrogen bonds.
  5. 5. Augustine Mai, Isaac Mandefro Period 8DNA replication DNA replication: Cells prepare for a cell division by doubling the DNA content of the cell Double quantity of DNA + one exact copy of each molecule Early event of DNA replication is separation of double helix into 2 strands Enzyme helicase causes separation of strands In nucleoplasm, there are many free floating nucleotides. Nucleotides available to form complementary pairs Formation of a covalent bond between two adjoining nucleotides is catalysed by one of the DNA polymerase enzymes thats important in the process.Significance of Complementary base pairings Pattern of DNA replication ensures 2 identical copies of DNA Every DNA molecule after replication has a strand that was old, now paired with a strand that is new
  6. 6. Augustine Mai, Isaac Mandefro Period 8